experimental psychology example

• The 25 Most Influential Psychological Experiments in History

While each year thousands and thousands of studies are completed in the many specialty areas of psychology, there are a handful that, over the years, have had a lasting impact in the psychological community as a whole. Some of these were dutifully conducted, keeping within the confines of ethical and practical guidelines. Others pushed the boundaries of human behavior during their psychological experiments and created controversies that still linger to this day. And still others were not designed to be true psychological experiments, but ended up as beacons to the psychological community in proving or disproving theories.

This is a list of the 25 most influential psychological experiments still being taught to psychology students of today.

1. A Class Divided

Study conducted by: jane elliott.

Study Conducted in 1968 in an Iowa classroom

Experiment Details: Jane Elliott’s famous experiment was inspired by the assassination of Dr. Martin Luther King Jr. and the inspirational life that he led. The third grade teacher developed an exercise, or better yet, a psychological experiment, to help her Caucasian students understand the effects of racism and prejudice.

Elliott divided her class into two separate groups: blue-eyed students and brown-eyed students. On the first day, she labeled the blue-eyed group as the superior group and from that point forward they had extra privileges, leaving the brown-eyed children to represent the minority group. She discouraged the groups from interacting and singled out individual students to stress the negative characteristics of the children in the minority group. What this exercise showed was that the children’s behavior changed almost instantaneously. The group of blue-eyed students performed better academically and even began bullying their brown-eyed classmates. The brown-eyed group experienced lower self-confidence and worse academic performance. The next day, she reversed the roles of the two groups and the blue-eyed students became the minority group.

At the end of the experiment, the children were so relieved that they were reported to have embraced one another and agreed that people should not be judged based on outward appearances. This exercise has since been repeated many times with similar outcomes.

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2. Asch Conformity Study

Study conducted by: dr. solomon asch.

Study Conducted in 1951 at Swarthmore College

Experiment Details: Dr. Solomon Asch conducted a groundbreaking study that was designed to evaluate a person’s likelihood to conform to a standard when there is pressure to do so.

A group of participants were shown pictures with lines of various lengths and were then asked a simple question: Which line is longest? The tricky part of this study was that in each group only one person was a true participant. The others were actors with a script. Most of the actors were instructed to give the wrong answer. Strangely, the one true participant almost always agreed with the majority, even though they knew they were giving the wrong answer.

The results of this study are important when we study social interactions among individuals in groups. This study is a famous example of the temptation many of us experience to conform to a standard during group situations and it showed that people often care more about being the same as others than they do about being right. It is still recognized as one of the most influential psychological experiments for understanding human behavior.

3. Bobo Doll Experiment

Study conducted by: dr. alburt bandura.

Study Conducted between 1961-1963 at Stanford University

In his groundbreaking study he separated participants into three groups:

• one was exposed to a video of an adult showing aggressive behavior towards a Bobo doll
• another was exposed to video of a passive adult playing with the Bobo doll
• the third formed a control group

Children watched their assigned video and then were sent to a room with the same doll they had seen in the video (with the exception of those in the control group). What the researcher found was that children exposed to the aggressive model were more likely to exhibit aggressive behavior towards the doll themselves. The other groups showed little imitative aggressive behavior. For those children exposed to the aggressive model, the number of derivative physical aggressions shown by the boys was 38.2 and 12.7 for the girls.

The study also showed that boys exhibited more aggression when exposed to aggressive male models than boys exposed to aggressive female models. When exposed to aggressive male models, the number of aggressive instances exhibited by boys averaged 104. This is compared to 48.4 aggressive instances exhibited by boys who were exposed to aggressive female models.

While the results for the girls show similar findings, the results were less drastic. When exposed to aggressive female models, the number of aggressive instances exhibited by girls averaged 57.7. This is compared to 36.3 aggressive instances exhibited by girls who were exposed to aggressive male models. The results concerning gender differences strongly supported Bandura’s secondary prediction that children will be more strongly influenced by same-sex models. The Bobo Doll Experiment showed a groundbreaking way to study human behavior and it’s influences.

4. Car Crash Experiment

Study conducted by: elizabeth loftus and john palmer.

Study Conducted in 1974 at The University of California in Irvine

The participants watched slides of a car accident and were asked to describe what had happened as if they were eyewitnesses to the scene. The participants were put into two groups and each group was questioned using different wording such as “how fast was the car driving at the time of impact?” versus “how fast was the car going when it smashed into the other car?” The experimenters found that the use of different verbs affected the participants’ memories of the accident, showing that memory can be easily distorted.

This research suggests that memory can be easily manipulated by questioning technique. This means that information gathered after the event can merge with original memory causing incorrect recall or reconstructive memory. The addition of false details to a memory of an event is now referred to as confabulation. This concept has very important implications for the questions used in police interviews of eyewitnesses.

5. Cognitive Dissonance Experiment

Study conducted by: leon festinger and james carlsmith.

Study Conducted in 1957 at Stanford University

Experiment Details: The concept of cognitive dissonance refers to a situation involving conflicting:

This conflict produces an inherent feeling of discomfort leading to a change in one of the attitudes, beliefs or behaviors to minimize or eliminate the discomfort and restore balance.

Cognitive dissonance was first investigated by Leon Festinger, after an observational study of a cult that believed that the earth was going to be destroyed by a flood. Out of this study was born an intriguing experiment conducted by Festinger and Carlsmith where participants were asked to perform a series of dull tasks (such as turning pegs in a peg board for an hour). Participant’s initial attitudes toward this task were highly negative.

They were then paid either $1 or $20 to tell a participant waiting in the lobby that the tasks were really interesting. Almost all of the participants agreed to walk into the waiting room and persuade the next participant that the boring experiment would be fun. When the participants were later asked to evaluate the experiment, the participants who were paid only $1 rated the tedious task as more fun and enjoyable than the participants who were paid $20 to lie.

Being paid only $1 is not sufficient incentive for lying and so those who were paid $1 experienced dissonance. They could only overcome that cognitive dissonance by coming to believe that the tasks really were interesting and enjoyable. Being paid $20 provides a reason for turning pegs and there is therefore no dissonance.

6. Fantz’s Looking Chamber

Study conducted by: robert l. fantz.

Study Conducted in 1961 at the University of Illinois

Experiment Details: The study conducted by Robert L. Fantz is among the simplest, yet most important in the field of infant development and vision. In 1961, when this experiment was conducted, there very few ways to study what was going on in the mind of an infant. Fantz realized that the best way was to simply watch the actions and reactions of infants. He understood the fundamental factor that if there is something of interest near humans, they generally look at it.

To test this concept, Fantz set up a display board with two pictures attached. On one was a bulls-eye. On the other was the sketch of a human face. This board was hung in a chamber where a baby could lie safely underneath and see both images. Then, from behind the board, invisible to the baby, he peeked through a hole to watch what the baby looked at. This study showed that a two-month old baby looked twice as much at the human face as it did at the bulls-eye. This suggests that human babies have some powers of pattern and form selection. Before this experiment it was thought that babies looked out onto a chaotic world of which they could make little sense.

7. Hawthorne Effect

Study conducted by: henry a. landsberger.

Study Conducted in 1955 at Hawthorne Works in Chicago, Illinois

Landsberger performed the study by analyzing data from experiments conducted between 1924 and 1932, by Elton Mayo, at the Hawthorne Works near Chicago. The company had commissioned studies to evaluate whether the level of light in a building changed the productivity of the workers. What Mayo found was that the level of light made no difference in productivity. The workers increased their output whenever the amount of light was switched from a low level to a high level, or vice versa.

The researchers noticed a tendency that the workers’ level of efficiency increased when any variable was manipulated. The study showed that the output changed simply because the workers were aware that they were under observation. The conclusion was that the workers felt important because they were pleased to be singled out. They increased productivity as a result. Being singled out was the factor dictating increased productivity, not the changing lighting levels, or any of the other factors that they experimented upon.

The Hawthorne Effect has become one of the hardest inbuilt biases to eliminate or factor into the design of any experiment in psychology and beyond.

8. Kitty Genovese Case

Study conducted by: new york police force.

Study Conducted in 1964 in New York City

Experiment Details: The murder case of Kitty Genovese was never intended to be a psychological experiment, however it ended up having serious implications for the field.

According to a New York Times article, almost 40 neighbors witnessed Kitty Genovese being savagely attacked and murdered in Queens, New York in 1964. Not one neighbor called the police for help. Some reports state that the attacker briefly left the scene and later returned to “finish off” his victim. It was later uncovered that many of these facts were exaggerated. (There were more likely only a dozen witnesses and records show that some calls to police were made).

What this case later become famous for is the “Bystander Effect,” which states that the more bystanders that are present in a social situation, the less likely it is that anyone will step in and help. This effect has led to changes in medicine, psychology and many other areas. One famous example is the way CPR is taught to new learners. All students in CPR courses learn that they must assign one bystander the job of alerting authorities which minimizes the chances of no one calling for assistance.

9. Learned Helplessness Experiment

Study conducted by: martin seligman.

Study Conducted in 1967 at the University of Pennsylvania

Seligman’s experiment involved the ringing of a bell and then the administration of a light shock to a dog. After a number of pairings, the dog reacted to the shock even before it happened. As soon as the dog heard the bell, he reacted as though he’d already been shocked.

During the course of this study something unexpected happened. Each dog was placed in a large crate that was divided down the middle with a low fence. The dog could see and jump over the fence easily. The floor on one side of the fence was electrified, but not on the other side of the fence. Seligman placed each dog on the electrified side and administered a light shock. He expected the dog to jump to the non-shocking side of the fence. In an unexpected turn, the dogs simply laid down.

The hypothesis was that as the dogs learned from the first part of the experiment that there was nothing they could do to avoid the shocks, they gave up in the second part of the experiment. To prove this hypothesis the experimenters brought in a new set of animals and found that dogs with no history in the experiment would jump over the fence.

This condition was described as learned helplessness. A human or animal does not attempt to get out of a negative situation because the past has taught them that they are helpless.

10. Little Albert Experiment

Study conducted by: john b. watson and rosalie rayner.

Study Conducted in 1920 at Johns Hopkins University

The experiment began by placing a white rat in front of the infant, who initially had no fear of the animal. Watson then produced a loud sound by striking a steel bar with a hammer every time little Albert was presented with the rat. After several pairings (the noise and the presentation of the white rat), the boy began to cry and exhibit signs of fear every time the rat appeared in the room. Watson also created similar conditioned reflexes with other common animals and objects (rabbits, Santa beard, etc.) until Albert feared them all.

This study proved that classical conditioning works on humans. One of its most important implications is that adult fears are often connected to early childhood experiences.

11. Magical Number Seven

Study conducted by: george a. miller.

Study Conducted in 1956 at Princeton University

Experiment Details:   Frequently referred to as “ Miller’s Law,” the Magical Number Seven experiment purports that the number of objects an average human can hold in working memory is 7 ± 2. This means that the human memory capacity typically includes strings of words or concepts ranging from 5-9. This information on the limits to the capacity for processing information became one of the most highly cited papers in psychology.

The Magical Number Seven Experiment was published in 1956 by cognitive psychologist George A. Miller of Princeton University’s Department of Psychology in Psychological Review .  In the article, Miller discussed a concurrence between the limits of one-dimensional absolute judgment and the limits of short-term memory.

In a one-dimensional absolute-judgment task, a person is presented with a number of stimuli that vary on one dimension (such as 10 different tones varying only in pitch). The person responds to each stimulus with a corresponding response (learned before).

Performance is almost perfect up to five or six different stimuli but declines as the number of different stimuli is increased. This means that a human’s maximum performance on one-dimensional absolute judgment can be described as an information store with the maximum capacity of approximately 2 to 3 bits of information There is the ability to distinguish between four and eight alternatives.

12. Pavlov’s Dog Experiment

Study conducted by: ivan pavlov.

Study Conducted in the 1890s at the Military Medical Academy in St. Petersburg, Russia

Pavlov began with the simple idea that there are some things that a dog does not need to learn. He observed that dogs do not learn to salivate when they see food. This reflex is “hard wired” into the dog. This is an unconditioned response (a stimulus-response connection that required no learning).

Pavlov outlined that there are unconditioned responses in the animal by presenting a dog with a bowl of food and then measuring its salivary secretions. In the experiment, Pavlov used a bell as his neutral stimulus. Whenever he gave food to his dogs, he also rang a bell. After a number of repeats of this procedure, he tried the bell on its own. What he found was that the bell on its own now caused an increase in salivation. The dog had learned to associate the bell and the food. This learning created a new behavior. The dog salivated when he heard the bell. Because this response was learned (or conditioned), it is called a conditioned response. The neutral stimulus has become a conditioned stimulus.

This theory came to be known as classical conditioning.

13. Robbers Cave Experiment

Study conducted by: muzafer and carolyn sherif.

Study Conducted in 1954 at the University of Oklahoma

Experiment Details: This experiment, which studied group conflict, is considered by most to be outside the lines of what is considered ethically sound.

In 1954 researchers at the University of Oklahoma assigned 22 eleven- and twelve-year-old boys from similar backgrounds into two groups. The two groups were taken to separate areas of a summer camp facility where they were able to bond as social units. The groups were housed in separate cabins and neither group knew of the other’s existence for an entire week. The boys bonded with their cabin mates during that time. Once the two groups were allowed to have contact, they showed definite signs of prejudice and hostility toward each other even though they had only been given a very short time to develop their social group. To increase the conflict between the groups, the experimenters had them compete against each other in a series of activities. This created even more hostility and eventually the groups refused to eat in the same room. The final phase of the experiment involved turning the rival groups into friends. The fun activities the experimenters had planned like shooting firecrackers and watching movies did not initially work, so they created teamwork exercises where the two groups were forced to collaborate. At the end of the experiment, the boys decided to ride the same bus home, demonstrating that conflict can be resolved and prejudice overcome through cooperation.

Many critics have compared this study to Golding’s Lord of the Flies novel as a classic example of prejudice and conflict resolution.

14. Ross’ False Consensus Effect Study

Study conducted by: lee ross.

Study Conducted in 1977 at Stanford University

Experiment Details: In 1977, a social psychology professor at Stanford University named Lee Ross conducted an experiment that, in lay terms, focuses on how people can incorrectly conclude that others think the same way they do, or form a “false consensus” about the beliefs and preferences of others. Ross conducted the study in order to outline how the “false consensus effect” functions in humans.

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In the first part of the study, participants were asked to read about situations in which a conflict occurred and then were told two alternative ways of responding to the situation. They were asked to do three things:

• Guess which option other people would choose
• Say which option they themselves would choose
• Describe the attributes of the person who would likely choose each of the two options

What the study showed was that most of the subjects believed that other people would do the same as them, regardless of which of the two responses they actually chose themselves. This phenomenon is referred to as the false consensus effect, where an individual thinks that other people think the same way they do when they may not. The second observation coming from this important study is that when participants were asked to describe the attributes of the people who will likely make the choice opposite of their own, they made bold and sometimes negative predictions about the personalities of those who did not share their choice.

15. The Schachter and Singer Experiment on Emotion

Study conducted by: stanley schachter and jerome e. singer.

Study Conducted in 1962 at Columbia University

Experiment Details: In 1962 Schachter and Singer conducted a ground breaking experiment to prove their theory of emotion.

In the study, a group of 184 male participants were injected with epinephrine, a hormone that induces arousal including increased heartbeat, trembling, and rapid breathing. The research participants were told that they were being injected with a new medication to test their eyesight. The first group of participants was informed the possible side effects that the injection might cause while the second group of participants were not. The participants were then placed in a room with someone they thought was another participant, but was actually a confederate in the experiment. The confederate acted in one of two ways: euphoric or angry. Participants who had not been informed about the effects of the injection were more likely to feel either happier or angrier than those who had been informed.

What Schachter and Singer were trying to understand was the ways in which cognition or thoughts influence human emotion. Their study illustrates the importance of how people interpret their physiological states, which form an important component of your emotions. Though their cognitive theory of emotional arousal dominated the field for two decades, it has been criticized for two main reasons: the size of the effect seen in the experiment was not that significant and other researchers had difficulties repeating the experiment.

16. Selective Attention / Invisible Gorilla Experiment

Study conducted by: daniel simons and christopher chabris.

Study Conducted in 1999 at Harvard University

Experiment Details: In 1999 Simons and Chabris conducted their famous awareness test at Harvard University.

Participants in the study were asked to watch a video and count how many passes occurred between basketball players on the white team. The video moves at a moderate pace and keeping track of the passes is a relatively easy task. What most people fail to notice amidst their counting is that in the middle of the test, a man in a gorilla suit walked onto the court and stood in the center before walking off-screen.

The study found that the majority of the subjects did not notice the gorilla at all, proving that humans often overestimate their ability to effectively multi-task. What the study set out to prove is that when people are asked to attend to one task, they focus so strongly on that element that they may miss other important details.

17. Stanford Prison Study

Study conducted by philip zimbardo.

Study Conducted in 1971 at Stanford University

The Stanford Prison Experiment was designed to study behavior of “normal” individuals when assigned a role of prisoner or guard. College students were recruited to participate. They were assigned roles of “guard” or “inmate.”  Zimbardo played the role of the warden. The basement of the psychology building was the set of the prison. Great care was taken to make it look and feel as realistic as possible.

The prison guards were told to run a prison for two weeks. They were told not to physically harm any of the inmates during the study. After a few days, the prison guards became very abusive verbally towards the inmates. Many of the prisoners became submissive to those in authority roles. The Stanford Prison Experiment inevitably had to be cancelled because some of the participants displayed troubling signs of breaking down mentally.

Although the experiment was conducted very unethically, many psychologists believe that the findings showed how much human behavior is situational. People will conform to certain roles if the conditions are right. The Stanford Prison Experiment remains one of the most famous psychology experiments of all time.

18. Stanley Milgram Experiment

Study conducted by stanley milgram.

Study Conducted in 1961 at Stanford University

Experiment Details: This 1961 study was conducted by Yale University psychologist Stanley Milgram. It was designed to measure people’s willingness to obey authority figures when instructed to perform acts that conflicted with their morals. The study was based on the premise that humans will inherently take direction from authority figures from very early in life.

Participants were told they were participating in a study on memory. They were asked to watch another person (an actor) do a memory test. They were instructed to press a button that gave an electric shock each time the person got a wrong answer. (The actor did not actually receive the shocks, but pretended they did).

Participants were told to play the role of “teacher” and administer electric shocks to “the learner,” every time they answered a question incorrectly. The experimenters asked the participants to keep increasing the shocks. Most of them obeyed even though the individual completing the memory test appeared to be in great pain. Despite these protests, many participants continued the experiment when the authority figure urged them to. They increased the voltage after each wrong answer until some eventually administered what would be lethal electric shocks.

This experiment showed that humans are conditioned to obey authority and will usually do so even if it goes against their natural morals or common sense.

19. Surrogate Mother Experiment

Study conducted by: harry harlow.

Study Conducted from 1957-1963 at the University of Wisconsin

Experiment Details: In a series of controversial experiments during the late 1950s and early 1960s, Harry Harlow studied the importance of a mother’s love for healthy childhood development.

In order to do this he separated infant rhesus monkeys from their mothers a few hours after birth and left them to be raised by two “surrogate mothers.” One of the surrogates was made of wire with an attached bottle for food. The other was made of soft terrycloth but lacked food. The researcher found that the baby monkeys spent much more time with the cloth mother than the wire mother, thereby proving that affection plays a greater role than sustenance when it comes to childhood development. They also found that the monkeys that spent more time cuddling the soft mother grew up to healthier.

This experiment showed that love, as demonstrated by physical body contact, is a more important aspect of the parent-child bond than the provision of basic needs. These findings also had implications in the attachment between fathers and their infants when the mother is the source of nourishment.

20. The Good Samaritan Experiment

Study conducted by: john darley and daniel batson.

Study Conducted in 1973 at The Princeton Theological Seminary (Researchers were from Princeton University)

Experiment Details: In 1973, an experiment was created by John Darley and Daniel Batson, to investigate the potential causes that underlie altruistic behavior. The researchers set out three hypotheses they wanted to test:

• People thinking about religion and higher principles would be no more inclined to show helping behavior than laymen.
• People in a rush would be much less likely to show helping behavior.
• People who are religious for personal gain would be less likely to help than people who are religious because they want to gain some spiritual and personal insights into the meaning of life.

Student participants were given some religious teaching and instruction. They were then were told to travel from one building to the next. Between the two buildings was a man lying injured and appearing to be in dire need of assistance. The first variable being tested was the degree of urgency impressed upon the subjects, with some being told not to rush and others being informed that speed was of the essence.

The results of the experiment were intriguing, with the haste of the subject proving to be the overriding factor. When the subject was in no hurry, nearly two-thirds of people stopped to lend assistance. When the subject was in a rush, this dropped to one in ten.

People who were on the way to deliver a speech about helping others were nearly twice as likely to help as those delivering other sermons,. This showed that the thoughts of the individual were a factor in determining helping behavior. Religious beliefs did not appear to make much difference on the results. Being religious for personal gain, or as part of a spiritual quest, did not appear to make much of an impact on the amount of helping behavior shown.

21. The Halo Effect Experiment

Study conducted by: richard e. nisbett and timothy decamp wilson.

Study Conducted in 1977 at the University of Michigan

Experiment Details: The Halo Effect states that people generally assume that people who are physically attractive are more likely to:

• be intelligent
• be friendly
• display good judgment

To prove their theory, Nisbett and DeCamp Wilson created a study to prove that people have little awareness of the nature of the Halo Effect. They’re not aware that it influences:

• their personal judgments
• the production of a more complex social behavior

In the experiment, college students were the research participants. They were asked to evaluate a psychology instructor as they view him in a videotaped interview. The students were randomly assigned to one of two groups. Each group was shown one of two different interviews with the same instructor. The instructor is a native French-speaking Belgian who spoke English with a noticeable accent. In the first video, the instructor presented himself as someone:

• respectful of his students’ intelligence and motives
• flexible in his approach to teaching
• enthusiastic about his subject matter

In the second interview, he presented himself as much more unlikable. He was cold and distrustful toward the students and was quite rigid in his teaching style.

After watching the videos, the subjects were asked to rate the lecturer on:

• physical appearance

His mannerisms and accent were kept the same in both versions of videos. The subjects were asked to rate the professor on an 8-point scale ranging from “like extremely” to “dislike extremely.” Subjects were also told that the researchers were interested in knowing “how much their liking for the teacher influenced the ratings they just made.” Other subjects were asked to identify how much the characteristics they just rated influenced their liking of the teacher.

After responding to the questionnaire, the respondents were puzzled about their reactions to the videotapes and to the questionnaire items. The students had no idea why they gave one lecturer higher ratings. Most said that how much they liked the lecturer had not affected their evaluation of his individual characteristics at all.

The interesting thing about this study is that people can understand the phenomenon, but they are unaware when it is occurring. Without realizing it, humans make judgments. Even when it is pointed out, they may still deny that it is a product of the halo effect phenomenon.

22. The Marshmallow Test

Study conducted by: walter mischel.

Study Conducted in 1972 at Stanford University

In his 1972 Marshmallow Experiment, children ages four to six were taken into a room where a marshmallow was placed in front of them on a table. Before leaving each of the children alone in the room, the experimenter informed them that they would receive a second marshmallow if the first one was still on the table after they returned in 15 minutes. The examiner recorded how long each child resisted eating the marshmallow and noted whether it correlated with the child’s success in adulthood. A small number of the 600 children ate the marshmallow immediately and one-third delayed gratification long enough to receive the second marshmallow.

In follow-up studies, Mischel found that those who deferred gratification were significantly more competent and received higher SAT scores than their peers. This characteristic likely remains with a person for life. While this study seems simplistic, the findings outline some of the foundational differences in individual traits that can predict success.

23. The Monster Study

Study conducted by: wendell johnson.

Study Conducted in 1939 at the University of Iowa

Experiment Details: The Monster Study received this negative title due to the unethical methods that were used to determine the effects of positive and negative speech therapy on children.

Wendell Johnson of the University of Iowa selected 22 orphaned children, some with stutters and some without. The children were in two groups. The group of children with stutters was placed in positive speech therapy, where they were praised for their fluency. The non-stutterers were placed in negative speech therapy, where they were disparaged for every mistake in grammar that they made.

As a result of the experiment, some of the children who received negative speech therapy suffered psychological effects and retained speech problems for the rest of their lives. They were examples of the significance of positive reinforcement in education.

The initial goal of the study was to investigate positive and negative speech therapy. However, the implication spanned much further into methods of teaching for young children.

24. Violinist at the Metro Experiment

Study conducted by: staff at the washington post.

Study Conducted in 2007 at a Washington D.C. Metro Train Station

During the study, pedestrians rushed by without realizing that the musician playing at the entrance to the metro stop was Grammy-winning musician, Joshua Bell. Two days before playing in the subway, he sold out at a theater in Boston where the seats average $100. He played one of the most intricate pieces ever written with a violin worth 3.5 million dollars. In the 45 minutes the musician played his violin, only 6 people stopped and stayed for a while. Around 20 gave him money, but continued to walk their normal pace. He collected $32.

The study and the subsequent article organized by the Washington Post was part of a social experiment looking at:

• the priorities of people

Gene Weingarten wrote about the social experiment: “In a banal setting at an inconvenient time, would beauty transcend?” Later he won a Pulitzer Prize for his story. Some of the questions the article addresses are:

• Do we perceive beauty?
• Do we stop to appreciate it?
• Do we recognize the talent in an unexpected context?

As it turns out, many of us are not nearly as perceptive to our environment as we might like to think.

25. Visual Cliff Experiment

Study conducted by: eleanor gibson and richard walk.

Study Conducted in 1959 at Cornell University

Experiment Details: In 1959, psychologists Eleanor Gibson and Richard Walk set out to study depth perception in infants. They wanted to know if depth perception is a learned behavior or if it is something that we are born with. To study this, Gibson and Walk conducted the visual cliff experiment.

They studied 36 infants between the ages of six and 14 months, all of whom could crawl. The infants were placed one at a time on a visual cliff. A visual cliff was created using a large glass table that was raised about a foot off the floor. Half of the glass table had a checker pattern underneath in order to create the appearance of a ‘shallow side.’

In order to create a ‘deep side,’ a checker pattern was created on the floor; this side is the visual cliff. The placement of the checker pattern on the floor creates the illusion of a sudden drop-off. Researchers placed a foot-wide centerboard between the shallow side and the deep side. Gibson and Walk found the following:

• Nine of the infants did not move off the centerboard.
• All of the 27 infants who did move crossed into the shallow side when their mothers called them from the shallow side.
• Three of the infants crawled off the visual cliff toward their mother when called from the deep side.
• When called from the deep side, the remaining 24 children either crawled to the shallow side or cried because they could not cross the visual cliff and make it to their mother.

What this study helped demonstrate is that depth perception is likely an inborn train in humans.

Among these experiments and psychological tests, we see boundaries pushed and theories taking on a life of their own. It is through the endless stream of psychological experimentation that we can see simple hypotheses become guiding theories for those in this field. The greater field of psychology became a formal field of experimental study in 1879, when Wilhelm Wundt established the first laboratory dedicated solely to psychological research in Leipzig, Germany. Wundt was the first person to refer to himself as a psychologist. Since 1879, psychology has grown into a massive collection of:

• methods of practice

It’s also a specialty area in the field of healthcare. None of this would have been possible without these and many other important psychological experiments that have stood the test of time.

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About the Author

After earning a Bachelor of Arts in Psychology from Rutgers University and then a Master of Science in Clinical and Forensic Psychology from Drexel University, Kristen began a career as a therapist at two prisons in Philadelphia. At the same time she volunteered as a rape crisis counselor, also in Philadelphia. After a few years in the field she accepted a teaching position at a local college where she currently teaches online psychology courses. Kristen began writing in college and still enjoys her work as a writer, editor, professor and mother.

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10 great psychology experiments

by Chris Woodford . Last updated: December 31, 2021.

S tare in the mirror and you'll find a strong sense of self staring back. Every one of us thinks we have a good idea who we are and what we're about—how we laugh and live and love, and all the complicated rest. But if you're a student of psychology —the fascinating science of human behaviour—you may well stare at your reflection with a wary eye. Because you'll know already that the ideas you have about yourself and other people can be very wide of the mark.

You might think you can learn a lot about human behaviour simply by observing yourself, but psychologists know that isn't really true. "Introspection" (thinking about yourself) has long been considered a suspect source of psychological research, even though one of the founding fathers of the science, William James, gained many important insights with its help. [1] Fortunately, there are thousands of rigorous experiments you can study that will do the job much more objectively and scientifically. And here's a quick selection of 10 of my favourites.

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1: are you really paying attention (simons & chabris, 1999).

“ ...our findings suggest that unexpected events are often overlooked... ” Simons & Chabris, 1999

You can read a book or you can listen to the radio, but can you do both at once? Maybe you can listen to a soft-rock album you've heard hundreds of times before and simultaneously plod your way through an undemanding crime novel, but how about listening to a complex political debate while trying to revise for a politics exam? What about listening to a German radio station while reading a French novel? What about mixing things up a bit more. You can iron your clothes while listening to the radio, no problem. But how about trying to follow (and visualize) the radio commentary on a football game while driving a highway you've never been along before? That's much more challenging because both things call on your brain's ability to process spatial information and one tends to interfere with the other. (There are very good reasons why it's unwise to use a cellphone while you're driving—and in some countries it's illegal.)

Generally speaking, we can do—and pay attention—to only so many things at once. That's no big surprise. However human attention works (and there are many theories about that), it's obviously not unlimited. What is surprising is how we pay attention to some things, in some situations, but not others. Psychologists have long studied something they call the cocktail-party effect . If you're at a noisy party, you can selectively switch your attention to any of the voices around you, just like tuning in a radio, while ignoring all the rest. Even more striking, if you're listening to one person and someone else happens to say your name, your ears will prick up and your attention will instantly switch to the other person instead. So your brain must be aware of much more than you think, even if it's not giving everything its full attention, all the time. [2]

Photo: Would you spot a gorilla if it were in plain sight? Picture by Richard Ruggiero courtesy of US Fish and Wildlife Service National Digital Library .

Sometimes, when we're really paying attention, we aren't easily distracted, even by drastic changes we ought to notice. A particularly striking demonstration of this comes from the work of Daniel Simons and Christopher Chabris (1999), who built on earlier work by the esteemed cognitive psychologist Ulric Neisser and colleagues. [3] Simons and Chabris made a video of people in black or white shirts throwing a basketball back and forth and asked viewers to count the number of passes made by the white-shirted players. You can watch it here .

Half the viewers failed to notice something else that happens at the same time (the gorilla-suited person wandering across the set)—an extraordinary example of something psychologists call inattentional blindness (in plain English: failure to see something you really should have spotted). A related phenomenon called change blindness explains why we generally fail to notice things like glaring continuity errors in movies: we don't expect to see them—and so we don't. Whether experiments like "the invisible gorilla" allow us to conclude broader things about human nature is a moot point, but it's certainly fair to say (as Simons and Chabris argue) that they reveal "critically important limitations of our cognitive abilities." None of us are as smart as we like to think, but just because we fail and fall short that doesn't make us bad people; we'd do a lot better if we understood and recognized our shortcomings. [4]

2: Are you trying too hard? (Aronson, 1966)

No-one likes a smart-aleck, so the saying goes, but just how true is that? Even if you really hate someone who has everything—the good looks, the great house, the well-paid job—it tuns out that there are certain circumstances in which you'll like them a whole lot more: if they suddenly make a stupid mistake. This not-entirely-surprising bit of psychology mirrors everyday experience: we like our fellow humans slightly flawed, down-to-earth, and somewhat relatable. Known as the pratfall effect , it was famously demonstrated back in 1966 by social psychologist Elliot Aronson. [5]

“ ...a superior person may be viewed as superhuman and, therefore, distant; a blunder tends to humanize him and, consequently, increases his attractiveness. ” Aronson et al, 1966

Aronson made taped audio recordings of two very different people talking about themselves and answering 50 difficult questions, which were supposedly part of an interview for a college quiz team. One person was very superior, got almost all the questions right, and revealed (in passing) that they were generally excellent at what they did (an honors student, yearbook editor, and member of the college track team). The other person was much more mediocre, got many questions wrong, and revealed (in passing) that they were much more of a plodder (average grades in high school, proofreader of the yearbook, and failed to make the track team). In the experiment, "subjects" (that's what psychologists call the people who take part in their trials) had to listen to the recordings of the two people and rate them on various things, including their likeability. But there was a twist. In some of the taped interviews, an extra bit (the "pratfall") was added at the end where either the superior person or the mediocrity suddenly shouted "Oh my goodness I've spilled coffee all over my new suit", accompanied by the sounds of a clattering chair and general chaos (noises that were identically spliced onto both tapes).

Artwork: Mistakes make you more likeable—if you're considered competent to begin with.

What Aronson found was that the superior person was rated more attractive with the pratfall at the end of their interview; the inferior person, less so. In other words, a pratfall can really work in your favor, but only if you're considered halfway competent to begin with; if not, it works against you. Knowingly or otherwise, smart celebrities and politicians often appear to take advantage of this to improve their popularity.

3: Is the past a foreign country? (Loftus and Palmer, 1974)

Attention isn't the only thing that lets us down; memory is hugely infallible too—and it's one of the strangest and most complex things psychologists study. Can you remember where you were when the Twin Towers fell in 2001 or (if you're much older and willing to go back further) when JFK was shot in Dallas in 1963? You might remember a girl you were in kindergarten with 20 years ago, but perhaps you can't remember the guy you met last week, last night, or even 10 minutes ago. What about the so-called tip-of-the-tongue phenomenon where you're certain you know a word or fact or name, and you can even describe what it's like ("It's a really short word, maybe beginning with 'F'..."), but you can't bring it instantly to mind? [6] How about the madeleine effect, where the taste or smell or something suddenly sets off an incredibly powerful involuntary memory ? What about déjà-vu : a jarring true-false memory—the strong sense something is very familiar when it can't possibly be? [7] How about the curious split between short- and long-term memories or between "procedural memory" (knowing how to do things or follow instructions) and "declarative memory" (knowing facts), which breaks down further into "semantic memory" (general knowledge about things) and "episodic memory" (specific things that have happened to you). What about the many flavors of selective memory failure, such as seniors who can remember the name of a high-school sweetheart but can't recall their own name? Or sudden episodes of amnesia? Human memory is a massive—and massively complex—subject. And any comprehensive theory of it needs to be able to explain a lot.

“ ...the questions asked subsequent to an event can cause a reconstruction in one's memory of that event.. ” Loftus & Palmer, 1974

Much of the time, poor memory is just a nuisance and we all have tricks for working around it—from slapping Post-It notes on the mirror to setting reminders on our phones. But there's one situation where poor memories can be a matter of life or death: in criminal investigation and court testimony. Suppose you give evidence in a trial based on events you think you remember that happened years ago—and suppose your evidence helps to convict a "murderer" who's subsequently sentenced to death. But what if your memory was quite wrong and the person was innocent?

One of the most famous studies of just how flawed our memories can be was made by psychologists Elizabeth Loftus and John Palmer in 1974. [8] After showing their subjects footage of a car accident, they tested their memories some time later by asking "About how fast were the cars going when they smashed into each other?" or using "collided," "bumped," "contacted," or "hit" in place of smashed. Those asked the first—leading—question reported higher speeds. Later, the subjects were asked if they'd seen any broken glass and those asked the leading question ("smashed") were much more likely to say "yes" even though there was no broken glass in the film. So our memories are much more fluid, far less fixed, than we suppose.

Artwork: The words we use to probe our memories can affect the memories we think we have.

This classic experiment very powerfully illustrates the potential unreliability of eyewitness testimony in criminal investigations, but the work of Elizabeth Loftus on so-called "false memory syndrome" has had far-reaching impacts in provocative areas, such as people's alleged recollections of alien abduction , multiple personality disorder , and memories of childhood abuse . Ultimately, what it demonstrates is that memory is fallible and remembering is sometimes less of a mechanical activity (pulling a dusty book from long-neglected library shelf) than a creative and recreative one (rewriting the book partly or completely to compensate for the fact that the print has faded with time). [9]

4. Do you cave in to peer pressure? (Milgram, 1963)

Experiments like the three we've considered so far might cast an uncomfortable shadow, yet most of us are still convinced we're rational, reasonable people, most of the time. Asked to predict how we'd behave in any given situation, we'd be able to give a pretty good account of ourselves—or so you might think. Consider the question of whether you'd ever, under any circumstances, torture another human being and you'd probably be appalled at the prospect. "Of course not!" And yet, as Yale University's Stanley Milgram famously demonstrated in the 1960s and 1970s, you'd probably be mistaken. [10]

Artwork: The Milgram experiment: a shocking turn of events.

Milgram's experiments on obedience to authority have been widely discussed and offered as explanations for all kinds of things, from minor everyday cruelty to the appalling catalogue of repugnant human behavior witnessed during the Nazi Holocaust. Today, they're generally considered unethical because they're deceptive and could, potentially, damage the mental health of people taking part in them (a claim Milgram himself investigated and refuted). [26]

“ ...the conflict stems from the opposition of two deeply ingrained behavior dispositions: first, the disposition not to harm other people, and second, the tendency to obey those whom we perceive to be legitimate authorities. ” Milgram, 1963

Though Milgram's studies have not been repeated, related experiments have sought to shed more light on why people find themselves participating in quite disturbing forms of behavior. One explanation is that, like willing actors, we simply assume the roles we're given and play our parts well. In 1972, Stanford University's Philip Zimbardo set up an entire "pretend prison" and assigned his subjects roles as prisoners or guards. Quite quickly, the guards went beyond simple play acting and actually took on the roles of sadistic bullies, exposing the prisoners to all kinds of rough and degrading treatment, while the prisoners resigned themselves to their fate or took on the roles of rebels. [11] More recently, Zimbardo has argued that his work sheds light on atrocities such as the torture at the Abu Ghraib prison in 2004, when US army guards were found to have tortured and degraded Iraqi prisoners under their guard in truly shocking ways.

5. Are you a slave to pleasure? (Olds and Milner, 1954)

Why do we do the things we do? Why do we eat or drink, play football, watch TV... or do the legions of other things we feel compelled to do each day? How, when we take these sorts of behaviors to extremes, do we become addicted to things like drink and drugs, gambling or sex? Are they ordinary pleasures taken to extremes or something altogether different? Obsessions, compulsions, and addictive behaviors are complex and very difficult to treat, but what causes them... and how do we treat them?

Artwork: A rat will happily stimulate the "pleasure centre" in its brain.

“ It appears that motivation, like sensation, has local centers in the brain. ” James Olds, Scientific American, 1956.

The Olds and Milner ICSS (intracranial self-stimulation) experiment was widely interpreted as the discovery of a "pleasure center" in the brain, but we have to take that suggestion with quite a pinch of salt. It's fascinating, but also quite reductively depressing, to imagine that a lot of the things humans feel compelled to do each day—from work and eating to sport and sex—are motivated by nothing more than the need to scratch a deep neural itch: to repeatedly stimulate a "hungry" part of our brain. While it offers important insights into addictive behavior, the idea that all of our complex human pleasure-seeking stems from something so crudely behavioral—stimulus and reward—seems absurdly over-simple. It's fascinating to search for references to Olds and Milner's work and see it quoted in books with such titles as Your Money and Your Brain: How the New Science of Neuroeconomics Can Help Make You Rich . But it's quite a stretch from a rat pushing on a pedal to making arguments of that kind. [14]

6: Are you asleep at the wheel? (Libet, 1983)

Being a conscious, active human being is a bit like driving a car: looking out through your eyes is like staring through a windshield, seeing (perceiving) things and responding to them, as they see and respond to you. Consciousness, in other words, feels like a "top-down" thing; like the driver of a car, we're always in control, willing the world to bend to our way, making things happen according to ideas our brains we devise beforehand. But how true is that really? If you are a driver, you'll know that much of what you do depends on a kind of mental "auto-pilot" or cruise control. As a practiced driver, you barely have to think about what you're doing at all—it's completely automatic. We're only really aware of just how effort-full and attentive drivers need to be when we first start learning. We soon learn to do most of the things involved in driving without being consciously aware of them at all—and that's true of other things too, not just driving a car. Seen this way, driving seems impressive—but if you think again about the Simons and Chabris gorilla experiment, and consider its implications for sitting behind the wheel, you might want to take the bus in future.

Still, you might think, you're always, ultimately, in charge and in control: you're the driver , not the passenger, even if you are sometimes dozy at the wheel. And yet, a remarkable series of experiments by Benjamin Libet, in the 1980s, appeared to demonstrate something entirely different: far from consciously making things happen, sometimes we become conscious of what we've done after the fact. In Libet's experiments, he made people watch a clock and move their wrist when it reached a certain time. But their brain activity (which he was also monitoring) showed a peak a fraction of a second before their conscious decision to move, suggesting, at least in this case, that consciousness is the effect, not the cause. [15]

“ Many of our mental functions are carried out unconsciously , without conscious awareness. ” Benjamin Libet, Mind Time, 2004, p.2.

On the face of it, Libet's work seems to have extraordinary implications for the study of consciousness. It's almost like we're zombies sitting at the wheel of a self-driving car. Is the whole idea of conscious free will just an illusion, an accidental artefact of knee-jerk behavior that happens much more automatically? You can certainly try to argue it that way, as many people have. On the other hand, it's important to remember that this is a highly constrained laboratory experiment and you can't automatically extrapolate from that to more general human behavior. (Apart from anything else, the methodology of Libet's experiments has been questioned. [16] ) While you could try to argue that a complex decision (to buy a house or quit your job) is made unconsciously or subconsciously in whatever manner and we rationalize or become conscious of it after the fact, experiments like Libet's aren't offering evidence for that. Sometimes, it's too much of a stretch to argue from simple, highly contrived, very abstract laboratory experiments to bigger, bolder, and more general everyday behavior.

On the other hand, it's quite likely that some behavior that we believe to be consciously pre-determined is anything but, as William James (and, independently, Carl Lange) reasoned way back in the late 19th century. In a famous example James offered, we assume we run from a scary bear because we see the bear and feel afraid. But James believed the reasoning here is back to front: we see the bear, run, and only feel afraid because we find ourselves running from a bear! (How we arrive at emotions is a whole huge topic of its own. The James-Lange theory eventually spawned more developed theories by Walter Cannon and Philip Bard, who believed emotions and their causes happen simultaneously, and Stanley Shachter and Jerome Singer, who believe emotions stem both from our bodily reactions and how we think about them.) [17]

7: Why are you so attached? (Harlow et al, 1971)

“ Love is a wondrous state, deep, tender, and rewarding. Because of its intimate and personal nature it is regarded by some as an improper topic for experimental research. ” Harry Harlow, 1958.

Artwork: Animals crave proper comfort, not just the simple "reduction" of "drives" like hunger. Photo courtesy of NASA and Wikimedia Commons .

There's an obvious evolutionary reason why we get attached to other people: one way or another, it improves our chances of surviving, mating, and passing on our genes to future generations. Attachment begins at birth, but our attachment to our mothers isn't motivated purely by a simple need for nourishment (through breastfeeding or whatever it might be). One of the most famous psychological experiments of all time demonstrated this back in the early 1970s. The University of Wisconsin's Harry Harlow and his wife Margaret tested what happened when newborn baby monkeys were separated from their mothers and "raised," instead by crude, mechanical surrogates. In particular, Harlow looked at how the monkeys behaved toward two rival "mothers", one with a wooden head and a wire body that had a feeding bottle attached, and one made from soft, warm, comforting cloth. Perhaps surprisingly, the babies preferred the cloth mother. Even when they ventured over to the wire mother for food, they soon returned to the cloth mother for comfort and reassurance. [18]

The fascinating thing about this study is that it suggests the need for comfort is at least as important as the (more obviously fundamental) need for nourishment, so busting the cold, harsh claims of hard-wired behaviorists, who believed our attachment to our mothers was all about mechanistic "drive reduction," or knee-jerk stimulus and response. Ultimately, we love the loving—Harlow's "contact comfort"—and perhaps things like habits, routines, and traditions can all be interpreted in this light.

8: Are you as rational as you think? (Wason, 1966)

“ ... I have concentrated mainly on the mistakes, assumptions, and stereotyped behavior which occur when people have to reason about abstract material. But... we seldom do reason about abstract material. ” Peter Wason, 1966.

Like everyone else, you probably have your moments of wild, reckless abandon, but faced with the task of making a calm, rational judgment about something, how well do you think you'd do? It's not a question of what you know or how clever you are, but how well you can make a judgment or a decision. Suppose, for example, you had to hire the best applicant for a job based on a pile of résumés. Or what if you had to find a new apartment by the end of the month and you had a limited selection to pick among. What if you were on the jury of a trial and had to sit through weeks or evidence to reach a verdict? How well do you think you'd do? Probably, given all the information, you feel you'd make a fair job of it: you have faith in your judgment. And yet, decades of research into human decision-making suggests you'll massively overestimate your own ability. Overconfident and under-informed, you'll jump to hasty conclusions, swayed by glaring biases you don't even notice. In the words of Daniel Kahneman, probably the world's leading expert on human rationality, your brain opts to think "fast" (reaches a quick and dirty decision) when sometimes it'd be better off thinking "slow" (reaching a more considered verdict). [25]

A classic demonstration of how poorly we think was devised by British psychologist Peter Wason in 1966. The experimenter puts a set of four white cards in front of you, each of which has a letter on one side and a number on the other. Then they tell you that if a card has a vowel on one side, it has an even number on the other side. Finally, they ask you which cards you need to turn over to verify if that statement is true. Suppose the cards show A, D, 4, and 7. The obvious answer, offered by most people, is A and 4 or just A. But the correct answer is actually A and 7. Once you've turned over A, it serves no purpose to turn over D or 4: turning over D tells us nothing, because it's not a vowel, while turning over 4 doesn't provide extra proof or disprove the statement. By turning over 7, however, you can potentially disprove the theory if you reveal a vowel on the other side of it. Wason's four-card test demonstrates what's known as "confirmation bias"—our failure to seek out evidence that contradicts things we believe. [19]

Artwork: Peter Wason's four-card selection test. If a card has a vowel on one side, it has an even number on the other. Which cards do you need to turn over to confirm this?

As with the other experiments here, you could extrapolate and argue that Wason's abstract reasoning test is echoed by bigger and wider failings we see in ourselves. Perhaps it goes some way to explaining things like online "echo chambers" and "filter bubbles", where we tend to watch, read, and listen to things that reinforce things we already believe—intellectual cloth mothers, you might call them—rather than challenging those comfortable beliefs or putting them to the test. But, again, a simple laboratory test is exactly what it is: a simple, laboratory test. And other, broader personal or social conclusions don't automatically follow on from it. (Indeed, you might recognize the tendency to argue that way as a confirmation bias all of its own.)

9: How do you learn things? (Pavlov, 1890s)

Learning might seem a very conscious and deliberate thing, especially if you hate the subject you're studying or merely sitting in school. What could be worse than "rote" learning your times table, practising French vocabulary, or revising for an exam? We also learn a lot of things less consciously—sometimes without any conscious effort at all. Animals (other than humans) don't sit in classrooms all day but they learn plenty of things. Even one of the simplest (a sea-slug called Aplysia californica ) will learn to withdraw its syphon and gill if you give it an electric shock, as Eric Kandel and James Schwartz famously discovered. [20]

“ The animal must respond to changes in the environment in such a manner that its responsive activity is directed toward the preservation of its existence. ” Ivan Pavlov, 1926.

So how does learning come about? At its most basic, it involves making connections or "associations" between things, something that was probed by Russian psychologist Ivan Pavlov in perhaps the most famous psychology experiment of all time. Pavlov looked at how dogs behave when he gave them food. Normally, he found dogs would salivate (a response) when he brought them a plate of food (a stimulus). We call this an unconditioned response (meaning default, normal, or just untrained): it's what the dogs do naturally. Now, with the food a distant doggy memory, Pavlov rang a bell (a neutral stimulus) and found it produced no response at all (the dogs didn't salivate). In the next phase of the experiment, he brought the dogs plates of food and rang a bell at the same time and found, again, that they salivated. So again, we have an unconditioned response, but this time to a pair of stimuli. Finally, after a period of this training, he tested what happened when he just rang the bell and, to his surprise, found that they salivated once again. In the jargon of psychology, we say the dogs had become "conditioned" to respond to the bell alone: they associated the bell with food and so responded by salivating. We call this a conditioned (trained or learned) response: the dogs have learned that the sound of the bell is generally linked to the appearance of food. [21]

Pavlov's work on conditioning was hugely influential—indeed, it was a key inspiration for the theory of behaviorism . Advanced by such luminaries as B.F. Skinner and J.B. Watson, this was the idea that animal behavior is largely a matter of stimulus and response and mental states—thinking, feeling, emoting, and reasoning—is irrelevant. But, as with all the other experiments here, it's a stretch to argue that we're all quasi-automated zombies raised in a kind of collective cloud of mind-control conditioning. It's true that we learn some things by simple, behavioural association, and animals like Aplysia may learn everything they know that way, but it doesn't follow that all animals learn everything by making endless daisy-chains of stimulus and response. [22]

10: You're happier than you realize (Seligman, 1975)

Money makes the world go round—or so goes the lyric of a famous song. But if you're American Martin Seligman, you'd probably think "happiness" was a better candidate for what powers the planet, or should. When I was studying psychology at college back in the mid-1980s, Professor Seligman came along to give a guest lecture—and it proved to be one of the most thought-provoking talks I would ever attend.

“ The time has finally arrived for a science that seeks to understand positive emotion, build strength and virtue, and provide guideposts for... 'the good life'. ” Martin Seligman, Authentic Happiness, 2003.

Though now widely and popularly known for his work in a field he calls positive psychology , Seligman originally made his name researching mental illness and how people came to be depressed. Taking a leaf from Pavlov's book, his subjects were dogs. Rather than feeding them and ringing bells, he studied what happened when he gave dogs electric shocks and either offered them an opportunity to escape or restrained them in a harness so they couldn't. What he discovered was that dogs that couldn't avoid the shocks became demoralised and depressed—they "learned helpnessness"—and eventually didn't even try to avoid punishment, even when (once again) they were allowed to. [23]

You can easily construct a whole (behavioural) theory of mental illness on the basis of Seligman's learned helplessness experiments but, once again, there's much more to it than that. People don't become depressed purely because they're in impossible situations where problems seem (to use the terminology) "internal" (their own fault), "global" (affecting all aspects of their life), and "stable" (impossible to change). Many different factors—neurochemical, behavioral, cognitive, and social—feed into depression and, as a result, there are just as many forms of treatment.

What's really interesting about Seligman's work is what he did next. In the 1990s, he realized psychologists were obsessed with mental illness and negativity when, in his view, they should probably spend more time figuring out what makes people happy. So began his more recent quest to understand "positive psychology" and the things we can all do to make our lives feel more fulfilled. The key, in his view, is working out and playing to what he calls our "signature strengths" (things we're good at that we enjoy doing). His ideas, which trace back to those early experiments on learned helpless in hapless dogs, have proved hugely influential, prompting many psychologists to switch their attention to developing a useful, practical "science of happiness." [24]

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For older readers, for younger readers, references ↑    see for example the classic discussion of consciousness in chapter 9: the stream of thought in principles of psychology (volume 1) by william james, henry holt, 1890. ↑    donald broadbent carried out notable early work on "selective attention" as this is called. see, for example, the role of auditory localization in attention and memory span by d.e. broadbent, j exp psychol, 1954, volume 47 number 3, pp.191–6. ↑     [pdf] gorillas in our midst: sustained inattentional blindness for dynamic events by daniel j simons, christopher f chabris, perception, 1999, volume 28, pp.1059–1074. ↑     the invisible gorilla and other ways our intuition deceives us by christopher chabris and daniel j. simons. harpercollins, 2010. ↑     [pdf] the effect of a pratfall on increasing interpersonal attractiveness by elliot aronson, ben willerman, and joanne floyd, psychon. sci., 1966, volume 4 number 6,pp.227–228. ↑     the 'tip of the tongue' phenomenon by roger brown and david mcneill, journal of verbal learning and verbal behavior, volume 5, issue 4, august 1966, pp.325–337. ↑     the cognitive neuropsychology of déjà vu by chris moulin, psychology press, 2017. ↑     reconstruction of automobile destruction: an example of the interaction between language and memory by elizabeth loftus and john palmer, journal of verbal learning & verbal behavior, volume 13 issue 5, pp.585–589. ↑     "that doesn't mean it really happened": an interview with elizabeth loftus by carrie poppy, the sceptical inquirer, september 8, 2016. ↑     behavioral study of obedience by stanley milgram, journal of abnormal and social psychology, 1963, volume 67, pp.371–378. ↑     a study of prisoners and guards in a simulated prison by craig haney, curtis banks, and philip zimbardo, naval research review, 1973, volume 30, pp.4–17. ↑     dr. robert g. heath: a controversial figure in the history of deep brain stimulation by christen m. o'neal et al, neurosurg focus 43 (3):e12, 2017. serendipity and the cerebral localization of pleasure by alan a. baumeister, journal of the history of the neurosciences, basic and clinical perspectives, volume 15, 2006. issue 2. the 'gay cure' experiments that were written out of scientific history by robert colvile, mosaic science, 4 july 2016. ↑     positive reinforcement produced by electrical stimulation of septal area and other regions of rat brain by j. olds and p. millner, j comp physiol psychol, 1954 dec;47(6):419–27. ↑     the pleasure areas by h.j. campbell, methuen, 1973. ↑     mind time: the temporal factor in consciousness by benjamin libet, harvard university press, 2004. ↑     exposing some holes in libet's classic free will study by christian jarrett, bps research digest, 2008. ↑    for a decent overview, see the section "theories of emotion" in 58: emotion in psychology by openstaxcollege. ↑     the nature of love by harry f. harlow, american psychologist, 13, pp.673–685. for a more general account, see love at goon park: harry harlow and the science of affection by by deborah blum, basic books, 2002. ↑     reasoning by p.c. wason, in foss, brian (ed.). new horizons in psychology. penguin, 1966, p.145. ↑     eric kandel and aplysia californica: their role in the elucidation of mechanisms of memory and the study of psychotherapy by michael robertson and garry walter, acta neuropsychiatrica, volume 22, issue 4, august 2010, pp.195–196. ↑     conditioned reflexes; an investigation of the physiological activity of the cerebral cortex by i.p pavlov. dover, 1960. ↑     pavlov's dogs by tim tully, current biology, 2003, volume 13, issue 4, 18 february 2003, pp.r117–r119. ↑     learned helplessness: theory and evidence by steven maier and martin seligman, journal of experimental psychology: general, 1976, volume 105, number 1, pp3.–46. ↑     authentic happiness by martin seligman, nicholas brealey, 2003. ↑     thinking fast and slow by daniel kahneman, penguin, 2011. ↑     subject reaction: the neglected factor in the ethics of experimentation by stanley milgram, the hastings center report, vol. 7, no. 5 (oct., 1977), pp. 19–23. please do not copy our articles onto blogs and other websites articles from this website are registered at the us copyright office. copying or otherwise using registered works without permission, removing this or other copyright notices, and/or infringing related rights could make you liable to severe civil or criminal penalties. text copyright © chris woodford 2021. all rights reserved. full copyright notice and terms of use . follow us, rate this page, tell your friends, cite this page, more to explore on our website....

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10 Cognitive Psychology Examples (Most Famous Experiments)

Dave Cornell (PhD)

Dr. Cornell has worked in education for more than 20 years. His work has involved designing teacher certification for Trinity College in London and in-service training for state governments in the United States. He has trained kindergarten teachers in 8 countries and helped businessmen and women open baby centers and kindergartens in 3 countries.

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Chris Drew (PhD)

This article was peer-reviewed and edited by Chris Drew (PhD). The review process on Helpful Professor involves having a PhD level expert fact check, edit, and contribute to articles. Reviewers ensure all content reflects expert academic consensus and is backed up with reference to academic studies. Dr. Drew has published over 20 academic articles in scholarly journals. He is the former editor of the Journal of Learning Development in Higher Education and holds a PhD in Education from ACU.

Cognitive psychology is the scientific study of mental processes. This includes trying to understand how people perceive the world around them, store and recall memories, acquire and use language, and engage in problem-solving.

Although not the first to study mental processes, Ulric Neisser helped cement the term in the field of psychology in his 1967 book Cognitive Psychology .

He offered an elaborate definition of cognitive psychology, with key points quoted below:

“ The term cognition refers to all processes by which sensory input is transformed, reduced, elaborated, recovered, and used…Giving such a sweeping definition, it is apparent that cognition is involved in everything a human being might possibly do” (p. 4).

In the mid-20 th century, there was significant divide in psychology between behaviorism and cognitive psychologists.

The behaviorists, such as Skinner, argued that only observable phenomena should be studied. Since mental processes could not be observed, they could not be studied scientifically.

Neisser countered, stating that:

“Cognitive processes surely exist, so it can hardly be unscientific to study them” (p. 5).  

Cognitive Psychology Examples (Famous Studies)

1. the forgetting curve and the serial position effect.

The contributions of Hermann Ebbinghaus to cognitive psychology were so significant that his individual studies could consume all 10 examples in this article.

Some believe that his book Über das Gedächtnis (1902) “…records one of the most remarkable research achievements in the history of psychology” (Roediger, 1985, p. 519).

Two of his most influential discoveries on memory include: the forgetting curve and the serial position effect .

To make his research on memory scientific, he created a list of over 2,000 nonsense syllables (e.g., BOK, YAT). Using commonly used vocabulary words would be too heavily associated with meaning, but nonsense syllables had no prior associations.

By conducting testing on himself, he was able to eliminate numerous other variables that would result from using people with varied backgrounds, experiences, and mental acuities.

So, he would present himself with lists of nonsense syllables and then test his memory at various intervals afterward.

This led to the discovery of the forgetting curve : forgetting begins right after the initial presentation of information and continues to degrade from then on.

The serial-position effect is the tendency to remember the first and last items in a list more so than the items in the middle.

2. The Magical Number 7 

One of the most often cited papers in psychology was written by cognitive psychologist George Miller of Harvard University in 1956.

The paper did not describe a series of experiments conducted by Miller himself. Instead, Miller outlines the work of several researchers that point to the magical number 7 as the capacity of short-term memory.

He made the case that this capacity is the same no matter what form the stimuli takes; whether talking about tones or words.

He also suggested that information is organized in “chunks,” not individual bits. A word is just one chunk for a native speaker, but for someone learning the language, the word consists of several bits of information in the form of individual letters.

Therefore, the capacity of the native speaker is 7 words, but for the beginner, it may only be two, or just 7 letters.

Miller concludes the paper by making a point about the number 7 itself:

“And finally, what about the magical number seven? What about the seven wonders of the world, the seven seas, the seven deadly sins, the seven daughters of Atlas in the Pleiades, the seven ages of man, the seven levels of hell, the seven primary colors, the seven notes of the musical scale, and the seven days of the week?” (p. 96).

See Also: Short-Term Memory Examples

3. The Framing Bias 

Tversky and Kahneman (1981) discovered the framing bias , which occurs when a person’s decision is influenced by the way information is presented. 

A typical study involved presenting information to participants, but varying one or two words in how the information was described.

For example:

“Imagine that the U.S. is preparing for the outbreak of an unusual Asian disease, which is expected to kill 600 people. If Program C is adopted 400 people will die. [22 percent] If Program D is adopted there is 1/3 probability that nobody will die, and 2/3 probability that 600 people will die. [78 percent] Which of the two programs would you favor?” (p. 453).

Although both programs lead to the same mortality rate, most research participants preferred Program D.

As the researchers explain, “the certain death of 400 people is less acceptable than the two-in-three chance that 600 will die” (p. 453).

Moreover, the effects were far from trivial:

“They occur when the outcomes concern the loss of human lives as well as in choices about money; they are not restricted to hypothetical questions and are not eliminated by monetary incentives” (p.  457).

4. Schema: Assimilation and Accommodation 

Jean Piaget’s research in the 1950’s and 60’s on cognitive development had a profound impact on our understanding of children. He detailed the way in which children perceive and make sense of the world and identified the stages of that developmental sequence which we still follow today.  

According to Piaget, children develop a schema , usually defined as a mental framework that organizes information about a concept.

As the child grows and experiences the world, everything they encounter will be processed within that schema. This is called assimilation . When the schema is altered or a new schema is developed, it is called accommodation .

He conducted a great deal of his research by observing his own three children and taking excruciatingly detailed notes on their behavior.

During the sensorimotor stage (birth to 2 years old), Piaget highlights a milestone that demonstrates the infant is now exploring their environment with intent.

“…the definitive conquest of the mechanisms of grasping marks the beginning of the complex behavior patterns which we shall call “assimilations through secondary schemata” and which characterize the first forms of deliberate action” (Piaget, 1956, p. 88).

Although this milestone takes place in the sensorimotor stage, it is much more than a sensory experience. It is driven by intent, a purely cognitive construct.

Priming occurs when exposure to a stimulus has an effect on our behavior or how we respond to information presented subsequently. It can occur outside of conscious awareness.  

Priming affects how we process all kinds of information and is a widely used concept in marketing.

Meyer and Schvaneveldt (1971) were among the first to study priming.

They presented research participants with various pairs of associated words (Bread/Butter), unassociated words (Bread/Doctor), or nonwords.

The participants were instructed to indicate “yes” if both words were real words or “no” if one was not a real word.

The results revealed that participants were able to make this decision much faster when the pair of words were associated than when they were unassociated.

Although not conclusive and in need of further research, this pattern indicated that words that have strong connections in memory are activated more easily than words that are less connected.

Research since has identified numerous types of priming, including: perceptual, semantic, associative, affective, and cultural.

6. Semantic Memory Network and Spreading Activation

Further research on priming was conducted by Collins and Loftus (1975). Their studies led to more conclusive evidence that information is stored in a memory network of linked concepts.

When one concept is activated, that activation spreads throughout the network and activates other concepts.

The stronger the connection between concepts, the more likely one will activate the other. Eventually, the activation loses energy and dissipates.

Collins and Loftus provide a thorough explanation of the semantic memory network :

“The more properties two concepts have in common, the more links there are between the two nodes via these properties and the more closely related are the concepts…When a concept is processed (or stimulated), activation spreads out along the paths of the network in a decreasing gradient” (p. 411).

This research led to a more complete understanding of how information is stored and organized in memory. This has helped us understand a wide range of psychological phenomena such as how we form impressions of others and make decisions.

7. The ELM Model of Persuasion

Understanding how people form an attitude has been an area of study in cognitive psychology for more than 50 years.

Researchers Petty and Cacioppo (1986) formulated the Elaboration Likelihood Model (ELM) of persuasion to explain how message factors and personality characteristics affect attitude formation.

The ELM identifies two routes to persuasion: central and peripheral.

The central route to persuasion is activated when the message recipient engages in a critical analysis of the message content. This occurs when the message is about an issue considered important by the recipient.

In this scenario, a person will be persuaded by the quality of arguments in the message.

The central route results

“…from a person’s careful and thoughtful consideration of the true merits of the information presented…” (1986, p. 125).

The peripheral route to persuasion involves very little cognitive processing of the message content. This occurs when the issue is unimportant to the recipient.

In this scenario, a person will be persuaded by the status of the person expressing their opinion.

The peripheral route results from:

“…some simple cue in the persuasion context (e.g., an attractive source) that induces change without necessitating scrutiny of the true merits of the information presented” (p. 125).

Findings from ELM research apply to everything from product advertising, to public health campaigns, to political debate.

Go Deeper: The Six Types of Persuasion

8. The Bobo Doll Study

The Bobo Doll study by Albert Bandura in 1963 may be one of the most famous studies in psychology and a founding study for the social cognitive theory . It had a tremendous impact on society as well.

It took place at a time in the U. S. in which there was great concern and debate over the growing prevalence of violence depicted on television.

In the study, children watched a video of an adult either playing violently or not violently with a Bobo doll.

Afterwards, each child was placed in a room with a Bobo doll. Their behavior was carefully observed by trained raters.

Children that watched the violent video were more aggressive towards the doll than those that watched the non-violent video.

This type of study was among the first demonstrate the powerful effect of television on children’s behavior. It led to decades of research and intense debate throughout society.

9. Bystander Intervention: The First Study

In 1964 in New York City, late at night, a young woman was murdered just steps away from her apartment.

The newspapers reported that nearly 40 residents heard her pleas for help, but that no one actually did anything. That reporting has now been found to have many inaccuracies.

However, the story created a national debate about crime and helping those in need.

This was the impetus for a study conducted by Latané and Darley (1968) on “ the bystander effect .”

The methodology was simple. Over 60 college students at New York University were taken to individual rooms to discuss an issue via an intercom system.

The students knew that several people would be participating in the discussion simultaneously.

One “participant” spoke about their difficulties adjusting to college life and their medical condition which sometimes led to seizures. This was a pre-recorded script and included a part where the “participant” acted as if they were feeling physical distress. They eventually stopped communicating with the other participants.

The results revealed that:

“The number of bystanders that the subject perceived to be present had a major effect on the likelihood with which she would report the emergency. Eighty-five percent of the subjects who thought they alone knew of the victim’s plight reported the seizure before the victim was cut off, only 31% of those who thought four other bystanders were present did so” (p. 379).

This was the beginning of a long program of research that identified the decision-making steps that determine the likelihood of a bystander intervening in an emergency situation.

10. The Car Crash Experiment: Leading Questions

Dr. Elizabeth Loftus and her undergraduate student John Palmer designed a study in 1974 that shook our confidence in eyewitness testimony.

Research participants watched videos that depicted accidents between two cars. Afterward, participants were asked to estimate how fast the two cars were traveling upon impact.  

“How fast were the two cars going when they ______ into each other?”

However, the word in the blank varied. For some participants the word in the blank was “smashed” and for other participants the word was “contacted.”

The results showed that estimates varied depending on the word.

When the word “smashed” was used, estimates were much higher than when the “contacted” was used. 

This was the first in a long line of research conducted on how phrasing can result in leading questions that affect the memory of eyewitnesses.

It has had a tremendous impact on law enforcement interrogation practices, line-up procedures, and the credibility of eyewitness testimony .

Today’s article was about 10 famous studies in cognitive psychology. Ten is actually a low number given how many studies have had substantial impact on the field.

The studies described above include the famous work of Ebbinghaus, who used himself as a test subject. This entire article could have consisted of his work.

Also included above was just one study by Tversky and Kahneman. The two researchers have identified so many heuristics and cognitive biases that only choosing one was just unfair.

Two studies by Loftus were included because they were both groundbreaking: one in memory and the other in eyewitness testimony.

Of course, Bandura’s Bobo Doll study was included because of its fame and impact on public discourse.

The ELM model and the earliest study on bystander intervention were also included. Both have had profound impacts in not just our understanding about the given subjects, but have also had substantial practical applications in various professions and matters in real-life.

Bandura, A. (1977).  Social Learning Theory . Prentice Hall.

Bandura, A., Ross, D., & Ross, S. A. (1963). Imitation of film-mediated aggressive models. The Journal of Abnormal and Social Psychology, 66 (1), 3–11. https://doi.org/10.1037/h0048687

Ebbinghaus, H. (1902). Grundz Üge der Psychologic. Leipzig, Germany: von Veit.

Ebbinghaus, H. (1964). Memory: A contribution to experimental psychology (H. A. Ruger, C. E. Bussenius translators). New York: Dover.

Ebbinghaus, H. (1913). On memory: A contribution to experimental psychology . New York: Teachers College.

Kitchen, P., Kerr, G., Schultz, D., Mccoll, R., & Pals, H. (2014). The elaboration likelihood model: Review, critique and research agenda. European Journal of Marketing, 48 (11/12), 2033-2050. https://doi.org/10.1108/EJM-12-2011-0776

Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction: An example of the interaction between language and memory. Journal of Verbal Learning and Verbal Behavior, 13 (5), 585–589.

Miller, G. A. (1956). The magical number seven plus or minus two: some limits on our capacity for processing information. Psychological Review , 63 (2), 81–97.

Neisser, U. (1967). Cognitive psychology . Englewood Cliffs, NJ: Prentice Hall.

Roediger, H. (1985). Remembering Ebbinghaus. PsycCRITIQUES, 30(7), 519-523.

Petty, R.E. & Cacioppo, J.T. (1986). The Elaboration Likelihood Model of persuasion. Advances in Experimental Social Psychology, 19 , 123-205. Doi: https://doi.org/10.1016/S0065-2601(08)60214-2

Piaget, J. (1956; 1965). The origins of intelligence in children . International Universities Press Inc. New York.

Tversky, A., & Kahneman, D. (1981). The framing of decisions and the psychology of choice .  Science ,  211 (4481), 453-458.

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The 11 Most Influential Psychological Experiments in History

The history of psychology is marked by groundbreaking experiments that transformed our understanding of the human mind. These 11 Most Influential Psychological Experiments in History stand out as pivotal, offering profound insights into behaviour, cognition, and the complexities of human nature.

In this PsychologyOrg article, we’ll explain these key experiments, exploring their impact on our understanding of human behaviour and the intricate workings of the mind.

Table of Contents

Experimental psychology.

Experimental psychology is a branch of psychology that uses scientific methods to study human behaviour and mental processes. Researchers in this field design experiments to test hypotheses about topics such as perception, learning, memory, emotion, and motivation.

They use a variety of techniques to measure and analyze behaviour and mental processes, including behavioural observations, self-report measures, physiological recordings, and computer simulations. The findings of experimental psychology studies can have important implications for a wide range of fields, including education, healthcare, and public policy.

Experimental Psychology, Psychologists have long tried to gain insight into how we perceive the world, to understand what motivates our behavior. They have made great strides in lifting that veil of mystery. In addition to providing us with food for stimulating party conversations, some of the most famous psychological experiments of the last century reveal surprising and universal truths about nature.

Throughout the history of psychology, revolutionary experiments have reshaped our comprehension of the human mind. These 11 experiments are pivotal, providing deep insights into human behaviour, cognition, and the intricate facets of human nature.

1. Kohler and the Chimpanzee experiment

Wolfgang Kohler studied the insight process by observing the behaviour of chimpanzees in a problem situation. In the experimental situation, the animals were placed in a cage outside of which food, for example, a banana, was stored. There were other objects in the cage, such as sticks or boxes. The animals participating in the experiment were hungry, so they needed to get to the food. At first, the chimpanzee used sticks mainly for playful activities; but suddenly, in the mind of the hungry chimpanzee, a relationship between sticks and food developed.

The cane, from an object to play with, became an instrument through which it was possible to reach the banana placed outside the cage. There has been a restructuring of the perceptual field: Kohler stressed that the appearance of the new behaviour was not the result of random attempts according to a process of trial and error. It is one of the first experiments on the intelligence of chimpanzees.

2. Harlow’s experiment on attachment with monkeys

In a scientific paper (1959), Harry F. Harlow described how he had separated baby rhesus monkeys from their mothers at birth, and raised them with the help of “puppet mothers”: in a series of experiments he compared the behavior of monkeys in two situations:

Little monkeys with a puppet mother without a bottle, but covered in a soft, fluffy, and furry fabric. Little monkeys with a “puppet” mother that supplied food, but was covered in wire. The little monkeys showed a clear preference for the “furry” mother, spending an average of fifteen hours a day attached to her, even though they were exclusively fed by the “suckling” puppet mother. conclusions of the Harlow experiment: all the experiments showed that the pleasure of contact elicited attachment behaviours, but the food did not.

3. The Strange Situation by Mary Ainsworth

Building on Bowlby’s attachment theory, Mary Ainsworth and colleagues (1978) have developed an experimental method called the Strange Situation, to assess individual differences in attachment security. The Strange Situation includes a series of short laboratory episodes in a comfortable environment and the child’s behaviors are observed.

Ainsworth and colleagues have paid special attention to the child’s behaviour at the time of reunion with the caregiver after a brief separation, thus identifying three different attachment patterns or styles, so called from that moment on. kinds of attachment according to Mary Ainsworth:

Secure attachment (63% of the dyads examined) Anxious-resistant or ambivalent (16%) Avoidant (21%) The Strange Situation by Mary Ainsworth

In a famous 1971 experiment, known as the Stanford Prison, Zimbardo and a team of collaborators reproduced a prison in the garages of Stanford University to study the behaviour of subjects in a context of very particular and complex dynamics. Let’s see how it went and the thoughts on the Stanford prison experiment. The participants (24 students) were randomly divided into two groups:

“ Prisoners “. The latter were locked up in three cells in the basement of a University building for six days; they were required to wear a white robe with a paper over it and a chain on the right ankle. “ Guards “. The students who had the role of prison guards had to watch the basement, choose the most appropriate methods to maintain order, and make the “prisoners” perform various tasks; they were asked to wear dark glasses and uniforms, and never to be violent towards the participants of the opposite role. However, the situation deteriorated dramatically: the fake police officers very soon began to seriously mistreat and humiliate the “detainees”, so it was decided to discontinue the experiment.

4. Jane Elliot’s Blue Eyes Experiment

On April 5, 1968, in a small school in Riceville, Iowa, Professor Jane Elliot decided to give a practical lesson on racism to 28 children of about eight years of age through the blue eyes brown eyes experiment.

“Children with brown eyes are the best,” the instructor began. “They are more beautiful and intelligent.” She wrote the word “melanin” on the board and explained that it was a substance that made people intelligent. Dark-eyed children have more, so they are more intelligent, while blue-eyed children “go hand in hand.”

In a very short time, the brown-eyed children began to treat their blue-eyed classmates with superiority, who in turn lost their self-confidence. A very good girl started making mistakes during arithmetic class, and at recess, she was approached by three little friends with brown eyes “You have to apologize because you get in their way and because we are the best,” said one of them. The girl hastened to apologize. This is one of the psychosocial experiments demonstrating how beliefs and prejudices play a role.

5. The Bobo de Bbandura doll

Albert Bandura gained great fame for the Bobo doll experiment on child imitation aggression, where:

A group of children took as an example, by visual capacity, the adults in a room, without their behaviour being commented on, hit the Bobo doll. Other contemporaries, on the other hand, saw adults sitting, always in absolute silence, next to Bobo.

Finally, all these children were brought to a room full of toys, including a doll like Bobo. Of the 10 children who hit the doll, 8 were those who had seen it done before by an adult. This explains how if a model that we follow performs a certain action, we are tempted to imitate it and this happens especially in children who still do not have the experience to understand for themselves if that behaviour is correct or not.

6. Milgram’s experiment

The Milgram experiment was first carried out in 1961 by psychologist Stanley Milgram, as an investigation into the degree of our deference to authority. A subject is invited to give an electric shock to an individual playing the role of the student, positioned behind a screen when he does not answer a question correctly. An authorized person then tells the subject to gradually increase the intensity of the shock until the student screams in pain and begs to stop.

No justification is given, except for the fact that the authorized person tells the subject to obey. In reality, it was staged: there was absolutely no electric shock given, but in the experiment two-thirds of the subjects were influenced by what they thought was a 450-volt shock, simply because a person in authority told them they would not be responsible for it. nothing.

7. little Albert

We see little Albert’s experiment on unconditioned stimulus, which must be the most famous psychological study. John Watson and Rosalie Raynor showed a white laboratory rat to a nine-month-old boy, little Albert. At first, the boy showed no fear, but then Watson jumped up from behind and made him flinch with a sudden noise by hitting a metal bar with a hammer. Of course, the noise frightened little Albert, who began to cry.

Every time the rat was brought out, Watson and Raynor would rattle the bar with their hammer to scare the poor boy away. Soon the mere sight of the rat was enough to reduce little Albert to a trembling bundle of nerves: he had learned to fear the sight of a rat, and soon afterwards began to fear a series of similar objects shown to him.

8. Pavlov’s dog

Ivan Pavlov’s sheepdog became famous for his experiments that led him to discover what we call “classical conditioning” or “Pavlovian reflex” and is still a very famous psychological experiment today. Hardly any other psychological experiment is cited so often and with such gusto as Pavlov’s theory expounded in 1905: the Russian physiologist had been impressed by the fact that his dogs did not begin to drool at the sight of food, but rather when they heard it. to the laboratory employees who took it away.

He researched it and ordered a buzzer to ring every time it was mealtime. Very soon the sound of the doorbell was enough for the dogs to start drooling: they had connected the signal to the arrival of food.

9. Asch’s experiment

It is about a social psychology experiment carried out in 1951 by the Polish psychologist Solomon Asch on the influence of the majority and social conformity.

The experiment is based on the idea that being part of a group is a sufficient condition to change a person’s actions, judgments, and visual perceptions. The very simple experiment consisted of asking the subjects involved to associate line 1 drawn on a white sheet with the corresponding one, choosing between three different lines A, B, and C present on another sheet. Only one was identical to the other, while the other two were longer or shorter.

The experimentation was carried out in three phases. As soon as one of the subjects, Asch’s accomplice gave a wrong answer associating line 1 with the wrong one, the other members of the group also made the same mistake, even though the correct answer was more than obvious. The participants questioned the reason for this choice and responded that aware of the correct answer, they had decided to conform to the group, adapting to those who had preceded them.

psychotherapy definition types and techniques | Psychotherapy vs therapy Psychologyorg.com

10. Rosenbaum’s experiment

Among the most interesting investigations in this field, an experiment carried out by David Rosenhan (1923) to document the low validity of psychiatric diagnoses stands out. Rosenhan admitted eight assistants to various psychiatric hospitals claiming psychotic symptoms, but once they entered the hospital they behaved as usual.

Despite this, they were held on average for 19 days, with all but one being diagnosed as “psychotic”. One of the reasons why the staff is not aware of the “normality” of the subjects, is, according to Rosenhan, the very little contact between the staff and the patients.

11. Bystander Effect (1968)

The Bystander Effect studied in 1968 after the tragic case of Kitty Genovese, explores how individuals are less likely to intervene in emergencies when others are present. The original research by John Darley and Bibb Latané involved staged scenarios where participants believed they were part of a discussion via intercom.

In the experiment, participants were led to believe they were communicating with others about personal problems. Unknown to them, the discussions were staged, and at a certain point, a participant (confederate) pretended to have a seizure or needed help.

The results were startling. When participants believed they were the sole witness to the emergency, they responded quickly and sought help. However, when they thought others were also present (but were confederates instructed to not intervene), the likelihood of any individual offering help significantly decreased. This phenomenon became known as the Bystander Effect.

The diffusion of responsibility, where individuals assume others will take action, contributes to this effect. The presence of others creates a diffusion of responsibility among bystanders, leading to a decreased likelihood of any single individual taking action.

This experiment highlighted the social and psychological factors influencing intervention during emergencies and emphasized the importance of understanding bystander behaviour in critical situations.

The journey through the “11 Most Influential Psychological Experiments in History” illuminates the profound impact these studies have had on our understanding of human behaviour, cognition, and social dynamics.

Each experiment stands as a testament to the dedication of pioneering psychologists who dared to delve into the complexities of the human mind. From Milgram’s obedience studies to Zimbardo’s Stanford Prison Experiment, these trials have shaped not only the field of psychology but also our societal perceptions and ethical considerations in research.

They serve as timeless benchmarks, reminding us of the ethical responsibilities and the far-reaching implications of delving into the human psyche. The enduring legacy of these experiments lies not only in their scientific contributions but also in the ethical reflections they provoke, urging us to navigate the boundaries of knowledge with caution, empathy, and an unwavering commitment to understanding the intricacies of our humanity.

What is the most famous experiment in the history of psychology?

One of the most famous experiments is the Milgram Experiment, conducted by Stanley Milgram in the 1960s. It investigated obedience to authority figures and remains influential in understanding human behaviour.

Who wrote the 25 most influential psychological experiments in history?

The book “The 25 Most Influential Psychological Experiments in History” was written by Michael Shermer, a science writer and historian of science.

What is the history of experimental psychology?

Experimental psychology traces back to Wilhelm Wundt, often considered the father of experimental psychology. He established the first psychology laboratory in 1879 at the University of Leipzig, marking the formal beginning of experimental psychology as a distinct field.

What was the psychological experiment in the 1960s?

Many significant psychological experiments were conducted in the 1960s. One notable example is the Stanford Prison Experiment led by Philip Zimbardo, which examined the effects of situational roles on behaviour.

Who was the first experimental psychologist?

Wilhelm Wundt is often regarded as the first experimental psychologist due to his establishment of the first psychology laboratory and his emphasis on empirical research methods in psychology.

If you want to read more articles similar to  The 11 Most Influential Psychological Experiments in History , we recommend that you enter our  Psychology  category.

I'm Waqar, a passionate psychologist and dedicated content writer. With a deep interest in understanding human behavior, I aim to share insights and knowledge in the field of psychology through this blog. Feel free to reach out for collaborations, queries, or discussions. Let's dig into the fascinating world of psychology together!

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B.A. in Psychology

What Is Experimental Psychology?

The science of psychology spans several fields. There are dozens of disciplines in psychology, including abnormal psychology, cognitive psychology and social psychology.

One way to view these fields is to separate them into two types: applied vs. experimental psychology. These groups describe virtually any type of work in psychology.

The following sections explore what experimental psychology is and some examples of what it covers.

Experimental psychology seeks to explore and better understand behavior through empirical research methods. This work allows findings to be employed in real-world applications (applied psychology) across fields such as clinical psychology, educational psychology, forensic psychology, sports psychology, and social psychology. Experimental psychology is able to shed light on people’s personalities and life experiences by examining what the way people behave and how behavior is shaped throughout life, along with other theoretical questions. The field looks at a wide range of behavioral topics including sensation, perception, attention, memory, cognition, and emotion, according to the  American Psychological Association  (APA).

Research is the focus of experimental psychology. Using scientific methods to collect data and perform research, experimental psychology focuses on certain questions, and, one study at a time, reveals information that contributes to larger findings or a conclusion. Due to the breadth and depth of certain areas of study, researchers can spend their entire careers looking at a complex research question.

Experimental Psychology in Action

The APA  writes about  one experimental psychologist, Robert McCann, who is now retired after 19 years working at NASA. During his time at NASA, his work focused on the user experience — on land and in space — where he applied his expertise to cockpit system displays, navigation systems, and safety displays used by astronauts in NASA spacecraft. McCann’s knowledge of human information processing allowed him to help NASA design shuttle displays that can increase the safety of shuttle missions. He looked at human limitations of attention and display processing to gauge what people can reliably see and correctly interpret on an instrument panel. McCann played a key role in helping determining the features of cockpit displays without overloading the pilot or taxing their attention span.

“One of the purposes of the display was to alert the astronauts to the presence of a failure that interrupted power in a specific region,” McCann said, “The most obvious way to depict this interruption was to simply remove (or dim) the white line(s) connecting the affected components. Basic research on visual attention has shown that humans do not notice the removal of a display feature very easily when the display is highly cluttered. We are much better at noticing a feature or object that is suddenly added to a display.” McCann utilized his knowledge in experimental psychology to research and develop this very important development for NASA. 

Valve Corporation

Another experimental psychologist, Mike Ambinder, uses his expertise to help design video games. He is a senior experimental psychologist at Valve Corporation, a video game developer and developer of the software distribution platform Steam. Ambinder told  Orlando Weekly  that his career working on gaming hits such as Portal 2 and Left 4 Dead “epitomizes the intersection between scientific innovation and electronic entertainment.” His career started when he gave a presentation to Valve on applying psychology to game design; this occurred while he was finishing his PhD in experimental design. “I’m very lucky to have landed at a company where freedom and autonomy and analytical decision-making are prized,” he said. “I realized how fortunate I was to work for a company that would encourage someone with a background in psychology to see what they could contribute in a field where they had no prior experience.” 

Ambinder spends his time on data analysis, hardware research, play-testing methodologies, and on any aspect of games where knowledge of human behavior could be useful. Ambinder described Valve’s process for refining a product as straightforward. “We come up with a game design (our hypothesis), and we place it in front of people external to the company (our play-test or experiment). We gather their feedback, and then iterate and improve the design (refining the theory). It’s essentially the scientific method applied to game design, and the end result is the consequence of many hours of applying this process.” To gather play-test data, Ambinder is engaged in the newer field of biofeedback technology, which can quantify gamers’ enjoyment. His research looks at unobtrusive measurements of facial expressions that can achieve such goals. Ambinder is also examining eye-tracking as a next-generation input method.

Pursue Your Career Goals in Psychology

Develop a greater understanding of psychology concepts and applications with Concordia St. Paul’s  online bachelor’s in psychology . Enjoy small class sizes with a personal learning environment geared toward your success, and learn from knowledgeable faculty who have industry experience. 

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experimental psychology

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• American Psychological Association - Understanding Experimental Psychology

experimental psychology , a method of studying psychological phenomena and processes. The experimental method in psychology attempts to account for the activities of animals (including humans) and the functional organization of mental processes by manipulating variables that may give rise to behaviour; it is primarily concerned with discovering laws that describe manipulable relationships. The term generally connotes all areas of psychology that use the experimental method.

These areas include the study of sensation and perception , learning and memory , motivation , and biological psychology . There are experimental branches in many other areas, however, including child psychology , clinical psychology , educational psychology , and social psychology . Usually the experimental psychologist deals with normal, intact organisms; in biological psychology, however, studies are often conducted with organisms modified by surgery, radiation, drug treatment, or long-standing deprivations of various kinds or with organisms that naturally present organic abnormalities or emotional disorders. See also psychophysics .

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What is Experimental Psychology?

Bryn Farnsworth

Table of Contents

The mind is a complicated place. Fortunately, the scientific method is perfectly equipped to deal with complexity. If we put these two things together we have the field of experimental psychology, broadly defined as the scientific study of the mind. The word “experimental” in this context means that tests are administered to participants, outcomes are measured, and comparisons are made.

More formally, this means that a group of participants are exposed to a stimulus (or stimuli), and their behavior in response is recorded. This behavior is compared to some kind of control condition, which could be either a neutral stimulus, the absence of a stimulus, or against a control group (who maybe do nothing at all).

Experimental psychology is concerned with testing theories of human thoughts, feelings, actions, and beyond – any aspect of being human that involves the mind. This is a broad category that features many branches within it (e.g. behavioral psychology , cognitive psychology). Below, we will go through a brief history of experimental psychology, the aspects that characterize it, and outline research that has gone on to shape this field.

A Brief History of Experimental Psychology

As with anything, and perhaps particularly with scientific ideas, it’s difficult to pinpoint the exact moment in which a thought or approach was conceived. One of the best candidates with which to credit the emergence of experimental psychology with is Gustav Fechner who came to prominence in the 1830’s. After completing his Ph.D in biology at the University of Leipzig [1], and continuing his work as a professor, he made a significant breakthrough in the conception of mental states.

Scientists later wrote about Fechner’s breakthrough for understanding perception: “An increase in the intensity of a stimulus, Fechner argued, does not produce a one-to-one increase in the intensity of the sensation … For example, adding the sound of one bell to that of an already ringing bell produces a greater increase in sensation than adding one bell to 10 others already ringing. Therefore, the effects of stimulus intensities are not absolute but are relative to the amount of sensation that already exists.” [2]

This ultimately meant that mental perception is responsive to the material world – the mind doesn’t passively respond to a stimulus (if that was the case, there would be a linear relationship between the intensity of a stimulus and the actual perception of it), but is instead dynamically responsive to it. This conception ultimately shapes much of experimental psychology, and the grounding theory: that the response of the brain to the environment can be quantified .

Fechner went on to research within this area for many subsequent years, testing new ideas regarding human perception. Meanwhile, another German scientist working in Heidelberg to the West, began his work on the problem of multitasking, and created the next paradigm shift for experimental psychology. The scientist was Wilhem Wundt, who had followed the work of Gustav Fechner.

Wilhem Wundt is often credited with being “the father of experimental psychology” and is the founding point for many aspects of it. He began the first experimental psychology lab, scientific journal, and ultimately formalized the approach as a science. Wundt set in stone what Fechner had put on paper.

The next scientist to advance the field of experimental psychology was influenced directly by reading Fechner’s book “ Elements of Psychophysics ”. Hermann Ebbinghaus, once again a German scientist, carried out the first properly formalized research into memory and forgetting, by using long lists of (mostly) nonsense syllables (such as: “VAW”, “TEL”, “BOC”) and recording how long it took for people to forget them.

Experiments using this list, concerning learning and memory, would take up much of Ebbinghaus’ career, and help cement experimental psychology as a science. There are many other scientists’ whose contributions helped pave the way for the direction, approach, and success of experimental psychology (Hermann von Helmholtz, Ernst Weber, and Mary Whiton Calkins, to name just a few) – all played a part in creating the field as we know it today. The work that they did defined the field, providing it with characteristics that we’ll now go through below.

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What Defines Experimental Psychology?

Defining any scientific field is in itself no exact science – there are inevitably aspects that will be missed. However, experimental psychology features at least three central components that define it: empiricism, falsifiability, and determinism . These features are central to experimental psychology but also many other fields within science.

Empiricism refers to the collection of data that can support or refute a theory. In opposition to purely theoretical reasoning, empiricism is concerned with observations that can be tested. It is based on the idea that all knowledge stems from observations that can be perceived, and data surrounding them can be collected to form experiments.

Falsifiability is a foundational aspect of all contemporary scientific work. Karl Popper , a 20th century philosopher, formalized this concept – that for any theory to be scientific there must be a way to falsify it. Otherwise, ludicrous, but unprovable claims could be made with equal weight as the most rigorously tested theories.

For example, the Theory of Relativity is scientific, for example, because it is possible that evidence could emerge to disprove it. This means that it can be tested. An example of an unfalsifiable argument is that the earth is younger than it appears, but that it was created to appear older than it is – any evidence against this is dismissed within the argument itself, rendering it impossible to falsify, and therefore untestable.

Determinism refers to the notion that any event has a cause before it. Applied to mental states, this means that the brain responds to stimuli, and that these responses can ultimately be predicted, given the correct data.

These aspects of experimental psychology run throughout the research carried out within this field. There are thousands of articles featuring research that have been carried out within this vein – below we will go through just a few of the most influential and well-cited studies that have shaped this field, and look to the future of experimental psychology.

Classic Studies in Experimental Psychology

Little albert.

One of the most notorious studies within experimental psychology was also one of the foundational pieces of research for behaviorism. Popularly known as the study of “Little Albert”, this experiment, carried out in 1920, focused on whether a baby could be made to fear a stimulus through conditioning (conditioning refers to the association of a response to a stimulus) [3].

The psychologist, John B. Watson , devised an experiment in which a baby was exposed to an unconditioned stimulus (in this case, a white rat) at the same time as a fear-inducing stimulus (the loud, sudden sound of a hammer hitting a metal bar). The repetition of this loud noise paired with the appearance of the white rat eventually led to the white rat becoming a conditioned stimulus – inducing the fear response even without the sound of the hammer.

While the study was clearly problematic, and wouldn’t (and shouldn’t!) clear any ethical boards today, it was hugely influential for its time, showing how human emotional responses can be shaped intentionally by conditioning – a feat only carried out with animals prior to this [4].

Watson, later referred to by a previous professor of his as a person “who thought too highly of himself and was more interested in his own ideas than in people” [5], was later revered and reviled in equal measure [2]. While his approach has since been rightly questioned, the study was a breakthrough for the conception of human behavior .

Asch’s Conformity Experiment

Three decades following Watson’s infamous experiment, beliefs were studied rather than behavior. Research carried out by Solomon Asch in 1951 showed how the influence of group pressure could make people say what they didn’t believe.

The goal was to examine how social pressures “induce individuals to resist or to yield to group pressures when the latter are perceived to be contrary to fact” [6]. Participant’s were introduced to a group of seven people in which, unbeknownst to them, all other individuals were actors hired by Asch. The task was introduced as a perceptual test, in which the length of lines was to be compared.

Sets of lines were shown to the group of participants – three on one card, one on another (as in the image above). The apparent task was to compare the three lines and say which was most like the single line in length. The answers were plainly obvious, and in one-on-one testing, participants got a correct answer over 99% of the time. Yet in this group setting, in which each actor, one after the other, incorrectly said an incorrect line out loud, the answers of the participants would change.

On average, around 38% of the answers the participants gave were incorrect – a huge jump from the less than 1% reported in non-group settings. The study was hugely influential for showing how our actions can be impacted by the environment we are placed in, particularly when it comes to social factors.

The Invisible Gorilla

If you don’t know this research from the title already, then it’s best experienced by watching the video below, and counting the number of ball passes.

The research of course has little to do with throwing a ball around, but more to do with the likelihood of not seeing the person in a gorilla costume who appears in the middle of the screen for eight seconds. The research, carried out in 1999, investigated how our attentional resources can impact how we perceive the world [7]. The term “ inattentional blindness ” refers to the effective blindness of our perceptions when our attention is engaged in another task.

The study tested how attentional processing is distributed, suggesting that objects that are more relevant to the task are more likely to be seen than objects which simply have close spatial proximity (very roughly – something expected is more likely to be seen even if it’s further away, whereas something unexpected is less likely to be seen even if it’s close).

The research not only showed the effect of our perceptions on our experience, but also has real-world implications. A replication of this study was done using eye tracking to record the visual search of radiologists who were instructed to look for nodules on one of several X-rays of lungs [8]. As the researchers state “A gorilla, 48 times the size of the average nodule, was inserted in the last case that was presented . Eighty-three percent of the radiologists did not see the gorilla.”

The original study, and research that followed since, has been crucial for showing how our expectations about the environment can shape our perceptions. Modern research has built upon each of the ideas and studies that have been carried out across almost 200 years.

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The Future of Experimental Psychology

The majority of this article has been concerned with what experimental psychology is, where it comes from, and what it has achieved so far. An inevitable follow-up question to this is – where is it going?

While predictions are difficult to make, there are at least indications. The best place to look is to experts in the field. Schultz and Schultz refer to modern psychology “as the science of behavior and mental processes instead of only behavior, a science seeking to explain overt behavior and its relationship to mental processes.” [2].

The Association for Psychological Science (APS) asked for forecasts from several prominent psychology researchers ( original article available here ), and received some of the following responses.

Lauri Nummenmaa (Assistant professor, Aalto University, Finland) predicts a similar path to Schultz and Schultz, stating that “a major aim of the future psychological science would involve re-establishing the link between the brain and behavior”. While Modupe Akinola (Assistant professor, Columbia Business School) hopes “that advancements in technology will allow for more unobtrusive ways of measuring bodily responses”.

Kristen Lindquist (Assistant professor of psychology, University of North Carolina School of Medicine) centers in on emotional responses, saying that “We are just beginning to understand how a person’s expectations, knowledge, and prior experiences shape his or her emotions. Emotions play a role in every moment of waking life from decisions to memories to feelings, so understanding emotions will help us to understand the mind more generally.”

Tal Yarkoni (Director, Psychoinformatics Lab, University of Texas at Austin) provides a forthright assessment of what the future of experimental psychology has in store: “psychological scientists will have better data, better tools, and more reliable methods of aggregation and evaluation”.

Whatever the future of experimental psychology looks like, we at iMotions aim to keep providing all the tools needed to carry out rigorous experimental psychology research.

I hope you’ve enjoyed reading this introduction to experimental psychology. If you’d like to get an even closer look at the background and research within this field, then download our free guide to human behavior below.

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[1] Shiraev, E. (2015). A history of psychology . Thousand Oaks, CA: SAGE Publications.

[2] Schultz, D. P., & Schultz, S. E. (2011). A History of Modern Psychology . Cengage, Canada.

[3] Watson, J.B.; Rayner, R. (1920). “Conditioned emotional reactions”. Journal of Experimental Psychology . 3 (1): 1–14. doi:10.1037/h0069608.

[4] Pavlov, I. P. (1928). Lectures on conditioned reflexes . (Translated by W.H. Gantt) London: Allen and Unwin.

[5] Brewer, C. L. (1991). Perspectives on John B. Watson . In G. A. Kimble, M. Wertheimer, & C. White (Eds.), Portraits of pioneers in psychology (pp. 171–186). Washington, DC: American Psychological Association.

[6] Asch, S.E. (1951). Effects of group pressure on the modification and distortion of judgments . In H. Guetzkow (Ed.), Groups, leadership and men(pp. 177–190). Pittsburgh, PA:Carnegie Press.

[7] Simons, D. and Chabris, C. (1999). Gorillas in our midst: sustained inattentional blindness for dynamic events. Perception , 28(9), pp.1059-1074.

[8] Drew, T., Võ, M. L-H., Wolfe, J. M. (2013). The invisible gorilla strikes again: sustained inattentional blindness in expert observers. Psychological Science, 24 (9):1848–1853. doi: 10.1177/0956797613479386.

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Famous Experiments

The Most Influential Psychological Experiments in History

Solomon Asch Conformity Line Experiment Study

Bandura's Bobo Doll Experiment on Social Learning

Reviewed by Olivia Guy-Evans, MSc

John Money Gender Experiment: Reimer Twins

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Van Ijzendoorn & Kroonenberg: Cultural Variations in Attachment

Jean piaget, behaviorism, neuroscience.

Jean Piaget's theory of cognitive development suggests that children move through four different stages of intellectual development which reflect the increasing sophistication of children's thoughts. Child development is determined by biological maturation and interaction with the environment.

Learn More: Piaget's Stages of Cognitive Development

Behaviorism is a theory of learning that states all behaviors are learned through interaction with the environment through a process called conditioning. Thus, behavior is simply a response to environmental stimuli.

Learn More: Behaviorist Approach in Psychology

Sigmund Freud (1856 to 1939) was the founding father of psychoanalysis, a method for treating mental illness and a theory that explains human behavior. His theories are clinically derived, based on what his patients told him during therapy.

Learn More: Sigmund Freud's Influence on Psychology

An approach is a perspective that involves certain assumptions about human behavior: the way people function, which aspects of them are worthy of study, and what research methods are appropriate for undertaking this study. The five major psychological perspectives are biological, psychodynamic, behaviorist, cognitive, and humanistic.

Learn More: Major Perspectives in Modern Psychology

Neuroscience is the branch of science concerned with studying the nervous system. It is a multidisciplinary field integrating numerous perspectives from biology, psychology, and medicine. It consists of several sub-fields ranging from the study of neurochemicals to the study of behavior and thought.

Learn More: What is Neuroscience?

Frequent Asked Questions

Is psychodynamic same as psychoanalytic?

The words psychodynamic and psychoanalytic are often confused. Remember that Freud’s theories were psychoanalytic, whereas the term ‘psychodynamic’ refers to both his theories and those of his followers, such as Carl Jung, Anna Freud, and Erik Erikson.

Learn More: Psychodynamic Approach

What is developmental psychology?

Developmental psychology is a scientific approach which aims to explain how thinking, feeling, and behavior change throughout a person’s life. A significant proportion of theories within this discipline focus upon development during childhood, as this is the period during an individual’s lifespan when the most change occurs.

Learn More: Developmental Psychology

What is Freud’s psychosexual theory?

Sigmund Freud proposed that personality development in childhood takes place during five psychosexual stages, which are the oral, anal, phallic, latency, and genital stages.

During each stage, sexual energy (libido) is expressed in different ways and through different body parts.

Learn More: Freud’s Psychosexual Stages of Development

What Is object permanence in Piaget’s theory?

Object permanence means knowing that an object still exists, even if it is hidden. It requires the ability to form a mental representation (i.e. a schema) of the object.

The attainment of object permanence generally signals the transition from the sensorimotor stage to the  preoperational stage of development .

Learn More: What Is Object Permanence According To Piaget?

What is the difference between a psychology and sociology?

Psychology studies the mind of an individual to understand human behavior and social and emotional reactions, whereas sociology looks beyond individuals and examines societal institutions and groups of people.

Learn More: Similarities and Differences Between Sociology and Psychology

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Little Hans - Freudian Case Study

Little Albert Experiment (Watson & Rayner)

Little Peter, Cover-Jones (1924)

Loftus and Palmer (1974): Car Crash Experiment

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11+ Psychology Experiment Ideas (Goals + Methods)

Have you ever wondered why some days you remember things easily, while on others you keep forgetting? Or why certain songs make you super happy and others just…meh?

Our minds are like big, mysterious puzzles, and every day we're finding new pieces to fit. One of the coolest ways to explore our brains and the way they work is through psychology experiments.

A psychology experiment is a special kind of test or activity researchers use to learn more about how our minds work and why we behave the way we do.

It's like a detective game where scientists ask questions and try out different clues to find answers about our feelings, thoughts, and actions. These experiments aren't just for scientists in white coats but can be fun activities we all try to discover more about ourselves and others.

Some of these experiments have become so famous, they’re like the celebrities of the science world! Like the Marshmallow Test, where kids had to wait to eat a yummy marshmallow, or Pavlov's Dogs, where dogs learned to drool just hearing a bell.

Let's look at a few examples of psychology experiments you can do at home.

What Are Some Classic Experiments?

Imagine a time when the mysteries of the mind were being uncovered in groundbreaking ways. During these moments, a few experiments became legendary, capturing the world's attention with their intriguing results.

The Marshmallow Test

One of the most talked-about experiments of the 20th century was the Marshmallow Test , conducted by Walter Mischel in the late 1960s at Stanford University.

The goal was simple but profound: to understand a child's ability to delay gratification and exercise self-control.

Children were placed in a room with a marshmallow and given a choice: eat the marshmallow now or wait 15 minutes and receive two as a reward. Many kids struggled with the wait, some devouring the treat immediately, while others demonstrated remarkable patience.

But the experiment didn’t end there. Years later, Mischel discovered something astonishing. The children who had waited for the second marshmallow were generally more successful in several areas of life, from school achievements to job satisfaction!

While this experiment highlighted the importance of teaching patience and self-control from a young age, it wasn't without its criticisms. Some argued that a child's background, upbringing, or immediate surroundings might play a significant role in their choices.

Moreover, there were concerns about the ethics of judging a child's potential success based on a brief interaction with a marshmallow.

Pavlov's Dogs

Traveling further back in time and over to Russia, another classic experiment took the world by storm. Ivan Pavlov , in the early 1900s, wasn't initially studying learning or behavior. He was exploring the digestive systems of dogs.

But during his research, Pavlov stumbled upon a fascinating discovery. He noticed that by ringing a bell every time he fed his dogs, they eventually began to associate the bell's sound with mealtime. So much so, that merely ringing the bell, even without presenting food, made the dogs drool in anticipation!

This reaction demonstrated the concept of "conditioning" - where behaviors can be learned by linking two unrelated stimuli. Pavlov's work revolutionized the world's understanding of learning and had ripple effects in various areas like animal training and therapy techniques.

Pavlov came up with the term classical conditioning , which is still used today. Other psychologists have developed more nuanced types of conditioning that help us understand how people learn to perform different behaviours.

Classical conditioning is the process by which a neutral stimulus becomes associated with a meaningful stimulus , leading to the same response. In Pavlov's case, the neutral stimulus (bell) became associated with the meaningful stimulus (food), leading the dogs to salivate just by hearing the bell.

Modern thinkers often critique Pavlov's methods from an ethical standpoint. The dogs, crucial to his discovery, may not have been treated with today's standards of care and respect in research.

Both these experiments, while enlightening, also underline the importance of conducting research with empathy and consideration, especially when it involves living beings.

What is Ethical Experimentation?

The tales of Pavlov's bells and Mischel's marshmallows offer us not just insights into the human mind and behavior but also raise a significant question: At what cost do these discoveries come?

Ethical experimentation isn't just a fancy term; it's the backbone of good science. When we talk about ethics, we're referring to the moral principles that guide a researcher's decisions and actions. But why does it matter so much in the realm of psychological experimentation?

An example of an experiment that had major ethical issues is an experiment called the Monster Study . This study was conducted in 1936 and was interested in why children develop a stutter.

The major issue with it is that the psychologists treated some of the children poorly over a period of five months, telling them things like “You must try to stop yourself immediately. Don’t ever speak unless you can do it right.”

You can imagine how that made the children feel!

This study helped create guidelines for ethical treatment in experiments. The guidelines include:

Respect for Individuals: Whether it's a dog in Pavlov's lab or a child in Mischel's study room, every participant—human or animal—deserves respect. They should never be subjected to harm or undue stress. For humans, informed consent (knowing what they're signing up for) is a must. This means that if a child is participating, they, along with their guardians, should understand what the experiment entails and agree to it without being pressured.

Honesty is the Best Policy: Researchers have a responsibility to be truthful. This means not only being honest with participants about the study but also reporting findings truthfully, even if the results aren't what they hoped for. There can be exceptions if an experiment will only succeed if the participants aren't fully aware, but it has to be approved by an ethics committee .

Safety First: No discovery, no matter how groundbreaking, is worth harming a participant. The well-being and mental, emotional, and physical safety of participants is paramount. Experiments should be designed to minimize risks and discomfort.

Considering the Long-Term: Some experiments might have effects that aren't immediately obvious. For example, while a child might seem fine after participating in an experiment, they could feel stressed or anxious later on. Ethical researchers consider and plan for these possibilities, offering support and follow-up if needed.

The Rights of Animals: Just because animals can't voice their rights doesn't mean they don't have any. They should be treated with care, dignity, and respect. This means providing them with appropriate living conditions, not subjecting them to undue harm, and considering alternatives to animal testing when possible.

While the world of psychological experiments offers fascinating insights into behavior and the mind, it's essential to tread with care and compassion. The golden rule? Treat every participant, human or animal, as you'd wish to be treated. After all, the true mark of a groundbreaking experiment isn't just its findings but the ethical integrity with which it's conducted.

So, even if you're experimenting at home, please keep in mind the impact your experiments could have on the people and beings around you!

Let's get into some ideas for experiments.

1) Testing Conformity

Our primary aim with this experiment is to explore the intriguing world of social influences, specifically focusing on how much sway a group has over an individual's decisions. This social influence is called groupthink .

Humans, as social creatures, often find solace in numbers, seeking the approval and acceptance of those around them. But how deep does this need run? Does the desire to "fit in" overpower our trust in our own judgments?

This experiment not only provides insights into these questions but also touches upon the broader themes of peer pressure, societal norms, and individuality. Understanding this could shed light on various real-world situations, from why fashion trends catch on to more critical scenarios like how misinformation can spread.

Method: This idea is inspired by the classic Asch Conformity Experiments . Here's a simple way to try it:

• Assemble a group of people (about 7-8). Only one person will be the real participant; the others will be in on the experiment.
• Show the group a picture of three lines of different lengths and another line labeled "Test Line."
• Ask each person to say out loud which of the three lines matches the length of the "Test Line."
• Unknown to the real participant, the other members will intentionally choose the wrong line. This is to see if the participant goes along with the group's incorrect choice, even if they can see it's wrong.

Real-World Impacts of Groupthink

Groupthink is more than just a science term; we see it in our daily lives:

Decisions at Work or School: Imagine being in a group where everyone wants to do one thing, even if it's not the best idea. People might not speak up because they're worried about standing out or being the only one with a different opinion.

Wrong Information: Ever heard a rumor that turned out to be untrue? Sometimes, if many people believe and share something, others might believe it too, even if it's not correct. This happens a lot on the internet.

Peer Pressure: Sometimes, friends might all want to do something that's not safe or right. People might join in just because they don't want to feel left out.

Missing Out on New Ideas: When everyone thinks the same way and agrees all the time, cool new ideas might never get heard. It's like always coloring with the same crayon and missing out on all the other bright colors!

2) Testing Color and Mood

We all have favorite colors, right? But did you ever wonder if colors can make you feel a certain way? Color psychology is the study of how colors can influence our feelings and actions.

For instance, does blue always calm us down? Does red make us feel excited or even a bit angry? By exploring this, we can learn how colors play a role in our daily lives, from the clothes we wear to the color of our bedroom walls.

• Find a quiet room and set up different colored lights or large sheets of colored paper: blue, red, yellow, and green.
• Invite some friends over and let each person spend a few minutes under each colored light or in front of each colored paper.
• After each color, ask your friends to write down or talk about how they feel. Are they relaxed? Energized? Happy? Sad?

Researchers have always been curious about this. Some studies have shown that colors like blue and green can make people feel calm, while colors like red might make them feel more alert or even hungry!

Real-World Impacts of Color Psychology

Ever noticed how different places use colors?

Hospitals and doctors' clinics often use soft blues and greens. This might be to help patients feel more relaxed and calm.

Many fast food restaurants use bright reds and yellows. These colors might make us feel hungry or want to eat quickly and leave.

Classrooms might use a mix of colors to help students feel both calm and energized.

3) Testing Music and Brainpower

Think about your favorite song. Do you feel smarter or more focused when you listen to it? This experiment seeks to understand the relationship between music and our brain's ability to remember things. Some people believe that certain types of music, like classical tunes, can help us study or work better. Let's find out if it's true!

• Prepare a list of 10-15 things to remember, like a grocery list or names of places.
• Invite some friends over. First, let them try to memorize the list in a quiet room.
• After a short break, play some music (try different types like pop, classical, or even nature sounds) and ask them to memorize the list again.
• Compare the results. Was there a difference in how much they remembered with and without music?

The " Mozart Effect " is a popular idea. Some studies in the past suggested that listening to Mozart's music might make people smarter, at least for a little while. But other researchers think the effect might not be specific to Mozart; it could be that any music we enjoy boosts our mood and helps our brain work better.

Real-World Impacts of Music and Memory

Think about how we use music:

• Study Sessions: Many students listen to music while studying, believing it helps them concentrate better.
• Workout Playlists: Gyms play energetic music to keep people motivated and help them push through tough workouts.
• Meditation and Relaxation: Calm, soothing sounds are often used to help people relax or meditate.

4) Testing Dreams and Food

Ever had a really wild dream and wondered where it came from? Some say that eating certain foods before bedtime can make our dreams more vivid or even a bit strange.

This experiment is all about diving into the dreamy world of sleep to see if what we eat can really change our nighttime adventures. Can a piece of chocolate or a slice of cheese transport us to a land of wacky dreams? Let's find out!

• Ask a group of friends to keep a "dream diary" for a week. Every morning, they should write down what they remember about their dreams.
• For the next week, ask them to eat a small snack before bed, like cheese, chocolate, or even spicy foods.
• They should continue writing in their "dream diary" every morning.
• At the end of the two weeks, compare the dream notes. Do the dreams seem different during the snack week?

The link between food and dreams isn't super clear, but some people have shared personal stories. For example, some say that spicy food can lead to bizarre dreams. Scientists aren't completely sure why, but it could be related to how food affects our body temperature or brain activity during sleep.

A cool idea related to this experiment is that of vivid dreams , which are very clear, detailed, and easy to remember dreams. Some people are even able to control their vivid dreams, or say that they feel as real as daily, waking life !

Real-World Impacts of Food and Dreams

Our discoveries might shed light on:

• Bedtime Routines: Knowing which foods might affect our dreams can help us choose better snacks before bedtime, especially if we want calmer sleep.
• Understanding Our Brain: Dreams can be mysterious, but studying them can give us clues about how our brains work at night.
• Cultural Beliefs: Many cultures have myths or stories about foods and dreams. Our findings might add a fun twist to these age-old tales!

5) Testing Mirrors and Self-image

Stand in front of a mirror. How do you feel? Proud? Shy? Curious? Mirrors reflect more than just our appearance; they might influence how we think about ourselves.

This experiment delves into the mystery of self-perception. Do we feel more confident when we see our reflection? Or do we become more self-conscious? Let's take a closer look.

• Set up two rooms: one with mirrors on all walls and another with no mirrors at all.
• Invite friends over and ask them to spend some time in each room doing normal activities, like reading or talking.
• After their time in both rooms, ask them questions like: "Did you think about how you looked more in one room? Did you feel more confident or shy?"
• Compare the responses to see if the presence of mirrors changes how they feel about themselves.

Studies have shown that when people are in rooms with mirrors, they can become more aware of themselves. Some might stand straighter, fix their hair, or even change how they behave. The mirror acts like an audience, making us more conscious of our actions.

Real-World Impacts of Mirrors and Self-perception

Mirrors aren't just for checking our hair. Ever wonder why clothing stores have so many mirrors? They might help shoppers visualize themselves in new outfits, encouraging them to buy.

Mirrors in gyms can motivate people to work out with correct form and posture. They also help us see progress in real-time!

And sometimes, looking in a mirror can be a reminder to take care of ourselves, both inside and out.

But remember, what we look like isn't as important as how we act in the world or how healthy we are. Some people claim that having too many mirrors around can actually make us more self conscious and distract us from the good parts of ourselves.

Some studies are showing that mirrors can actually increase self-compassion , amongst other things. As any tool, it seems like mirrors can be both good and bad, depending on how we use them!

6) Testing Plants and Talking

Have you ever seen someone talking to their plants? It might sound silly, but some people believe that plants can "feel" our vibes and that talking to them might even help them grow better.

In this experiment, we'll explore whether plants can indeed react to our voices and if they might grow taller, faster, or healthier when we chat with them.

• Get three similar plants, placing each one in a separate room.
• Talk to the first plant, saying positive things like "You're doing great!" or singing to it.
• Say negative things to the second plant, like "You're not growing fast enough!"
• Don't talk to the third plant at all; let it be your "silent" control group .
• Water all plants equally and make sure they all get the same amount of light.
• At the end of the month, measure the growth of each plant and note any differences in their health or size.

The idea isn't brand new. Some experiments from the past suggest plants might respond to sounds or vibrations. Some growers play music for their crops, thinking it helps them flourish.

Even if talking to our plants doesn't have an impact on their growth, it can make us feel better! Sometimes, if we are lonely, talking to our plants can help us feel less alone. Remember, they are living too!

Real-World Impacts of Talking to Plants

If plants do react to our voices, gardeners and farmers might adopt new techniques, like playing music in greenhouses or regularly talking to plants.

Taking care of plants and talking to them could become a recommended activity for reducing stress and boosting mood.

And if plants react to sound, it gives us a whole new perspective on how connected all living things might be .

7) Testing Virtual Reality and Senses

Virtual reality (VR) seems like magic, doesn't it? You put on a headset and suddenly, you're in a different world! But how does this "new world" affect our senses? This experiment wants to find out how our brains react to VR compared to the real world. Do we feel, see, or hear things differently? Let's get to the bottom of this digital mystery!

• You'll need a VR headset and a game or experience that can be replicated in real life (like walking through a forest). If you don't have a headset yourself, there are virtual reality arcades now!
• Invite friends to first experience the scenario in VR.
• Afterwards, replicate the experience in the real world, like taking a walk in an actual forest.
• Ask them questions about both experiences: Did one seem more real than the other? Which sounds were more clear? Which colors were brighter? Did they feel different emotions?

As VR becomes more popular, scientists have been curious about its effects. Some studies show that our brains can sometimes struggle to tell the difference between VR and reality. That's why some people might feel like they're really "falling" in a VR game even though they're standing still.

Real-World Impacts of VR on Our Senses

Schools might use VR to teach lessons, like taking students on a virtual trip to ancient Egypt. Understanding how our senses react in VR can also help game designers create even more exciting and realistic games.

Doctors could use VR to help patients overcome fears or to provide relaxation exercises. This is actually already a method therapists can use for helping patients who have serious phobias. This is called exposure therapy , which basically means slowly exposing someone (or yourself) to the thing you fear, starting from very far away to becoming closer.

For instance, if someone is afraid of snakes. You might show them images of snakes first. Once they are comfortable with the picture, they can know there is one in the next room. Once they are okay with that, they might use a VR headset to see the snake in the same room with them, though of course there is not an actual snake there.

8) Testing Sleep and Learning

We all know that feeling of trying to study or work when we're super tired. Our brains feel foggy, and it's hard to remember stuff. But how exactly does sleep (or lack of it) influence our ability to learn and remember things?

With this experiment, we'll uncover the mysteries of sleep and see how it can be our secret weapon for better learning.

• Split participants into two groups.
• Ask both groups to study the same material in the evening.
• One group goes to bed early, while the other stays up late.
• The next morning, give both groups a quiz on what they studied.
• Compare the results to see which group remembered more.

Sleep and its relation to learning have been explored a lot. Scientists believe that during sleep, especially deep sleep, our brains sort and store new information. This is why sometimes, after a good night's rest, we might understand something better or remember more.

Real-World Impacts of Sleep and Learning

Understanding the power of sleep can help:

• Students: If they know the importance of sleep, students might plan better, mixing study sessions with rest, especially before big exams.
• Workplaces: Employers might consider more flexible hours, understanding that well-rested employees learn faster and make fewer mistakes.
• Health: Regularly missing out on sleep can have other bad effects on our health. So, promoting good sleep is about more than just better learning.

9) Testing Social Media and Mood

Have you ever felt different after spending time on social media? Maybe happy after seeing a friend's fun photos, or a bit sad after reading someone's tough news.

Social media is a big part of our lives, but how does it really affect our mood? This experiment aims to shine a light on the emotional roller-coaster of likes, shares, and comments.

• Ask participants to note down how they're feeling - are they happy, sad, excited, or bored?
• Have them spend a set amount of time (like 30 minutes) on their favorite social media platforms.
• After the session, ask them again about their mood. Did it change? Why?
• Discuss what they saw or read that made them feel that way.

Previous research has shown mixed results. Some studies suggest that seeing positive posts can make us feel good, while others say that too much time on social media can make us feel lonely or left out.

Real-World Impacts of Social Media on Mood

Understanding the emotional impact of social media can help users understand their feelings and take breaks if needed. Knowing is half the battle! Additionally, teachers and parents can guide young users on healthy social media habits, like limiting time or following positive accounts.

And if it's shown that social media does impact mood, social media companies can design friendlier, less stressful user experiences.

But even if the social media companies don't change things, we can still change our social media habits to make ourselves feel better.

10) Testing Handwriting or Typing

Think about the last time you took notes. Did you grab a pen and paper or did you type them out on a computer or tablet?

Both ways are popular, but there's a big question: which method helps us remember and understand better? In this experiment, we'll find out if the classic art of handwriting has an edge over speedy typing.

• Divide participants into two groups.
• Present a short lesson or story to both groups.
• One group will take notes by hand, while the other will type them out.
• After some time, quiz both groups on the content of the lesson or story.
• Compare the results to see which note-taking method led to better recall and understanding.

Studies have shown some interesting results. While typing can be faster and allows for more notes, handwriting might boost memory and comprehension because it engages the brain differently, making us process the information as we write.

Importantly, each person might find one or the other works better for them. This could be useful in understanding our learning habits and what instructional style would be best for us.

Real-World Impacts of Handwriting vs. Typing

Knowing the pros and cons of each method can:

• Boost Study Habits: Students can pick the method that helps them learn best, especially during important study sessions or lectures.
• Work Efficiency: In jobs where information retention is crucial, understanding the best method can increase efficiency and accuracy.
• Tech Design: If we find out more about how handwriting benefits us, tech companies might design gadgets that mimic the feel of writing while combining the advantages of digital tools.

11) Testing Money and Happiness

We often hear the saying, "Money can't buy happiness," but is that really true? Many dream of winning the lottery or getting a big raise, believing it would solve all problems.

In this experiment, we dig deep to see if there's a real connection between wealth and well-being.

• Survey a range of participants, from those who earn a little to those who earn a lot, about their overall happiness. You can keep it to your friends and family, but that might not be as accurate as surveying a wider group of people.
• Ask them to rank things that bring them joy and note if they believe more money would boost their happiness. You could try different methods, one where you include some things that they have to rank, such as gardening, spending time with friends, reading books, learning, etc. Or you could just leave a blank list that they can fill in with their own ideas.
• Study the data to find patterns or trends about income and happiness.

Some studies have found money can boost happiness, especially when it helps people out of tough financial spots. But after reaching a certain income, extra dollars usually do not add much extra joy.

In fact, psychologists just realized that once people have an income that can comfortably support their needs (and some of their wants), they stop getting happier with more . That number is roughly $75,000, but of course that depends on the cost of living and how many members are in the family.

Real-World Impacts of Money and Happiness

If we can understand the link between money and joy, it might help folks choose jobs they love over jobs that just pay well. And instead of buying things, people might spend on experiences, like trips or classes, that make lasting memories.

Most importantly, we all might spend more time on hobbies, friends, and family, knowing they're big parts of what makes life great.

Some people are hoping that with Artificial Intelligence being able to do a lot of the less well-paying jobs, people might be able to do work they enjoy more, all while making more money and having more time to do the things that make them happy.

12) Testing Temperature and Productivity

Have you ever noticed how a cold classroom or office makes it harder to focus? Or how on hot days, all you want to do is relax? In this experiment, we're going to find out if the temperature around us really does change how well we work.

• Find a group of participants and a room where you can change the temperature.
• Set the room to a chilly temperature and give the participants a set of tasks to do.
• Measure how well and quickly they do these tasks.
• The next day, make the room comfortably warm and have them do similar tasks.
• Compare the results to see if the warmer or cooler temperature made them work better.

Some studies have shown that people can work better when they're in a room that feels just right, not too cold or hot. Being too chilly can make fingers slow, and being too warm can make minds wander.

What temperature is "just right"? It won't be the same for everyone, but most people find it's between 70-73 degrees Fahrenheit (21-23 Celsius).

Real-World Implications of Temperature and Productivity

If we can learn more about how temperature affects our work, teachers might set classroom temperatures to help students focus and learn better, offices might adjust temperatures to get the best work out of their teams, and at home, we might find the best temperature for doing homework or chores quickly and well.

Interestingly, temperature also has an impact on our sleep quality. Most people find slightly cooler rooms to be better for good sleep. While the daytime temperature between 70-73F is good for productivity, a nighttime temperature around 65F (18C) is ideal for most people's sleep.

Psychology is like a treasure hunt, where the prize is understanding ourselves better. With every experiment, we learn a little more about why we think, feel, and act the way we do. Some of these experiments might seem simple, like seeing if colors change our mood or if being warm helps us work better. But even the simple questions can have big answers that help us in everyday life.

Remember, while doing experiments is fun, it's also important to always be kind and think about how others feel. We should never make someone uncomfortable just for a test. Instead, let's use these experiments to learn and grow, helping to make the world a brighter, more understanding place for everyone.

Related posts:

• 150+ Flirty Goodnight Texts For Him (Sweet and Naughty Examples)
• Dream Interpreter & Dictionary (270+ Meanings)
• Sleep Stages (Light, Deep, REM)
• What Part of the Brain Regulates Body Temperature?
• Why Do We Dream? (6 Theories and Psychological Reasons)

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7 Famous Psychology Experiments

Many famous experiments studying human behavior have impacted our fundamental understanding of psychology. Though some could not be repeated today due to breaches in ethical boundaries, that does not diminish the significance of those psychological studies. Some of these important findings include a greater awareness of depression and its symptoms, how people learn behaviors through the process of association and how individuals conform to a group.

Below, we take a look at seven famous psychological experiments that greatly influenced the field of psychology and our understanding of human behavior.

The Little Albert Experiment, 1920

A John’s Hopkins University professor, Dr. John B. Watson, and a graduate student wanted to test a learning process called classical conditioning. Classical conditioning involves learning involuntary or automatic behaviors by association, and Dr. Watson thought it formed the bedrock of human psychology.

A nine-month-old toddler, dubbed “Albert B,” was volunteered for Dr. Watson and Rosalie Rayner ‘s experiment. Albert played with white furry objects, and at first, the toddler displayed joy and affection. Over time, as he played with the objects, Dr. Watson would make a loud noise behind the child’s head to frighten him. After numerous trials, Albert was conditioned to be afraid when he saw white furry objects.

The study proved that humans could be conditioned to enjoy or fear something, which many psychologists believe could explain why people have irrational fears and how they may have developed early in life. This is a great example of experimental study psychology.

Stanford Prison Experiment, 1971

Stanford professor Philip Zimbardo wanted to learn how individuals conformed to societal roles. He wondered, for example, whether the tense relationship between prison guards and inmates in jails had more to do with the personalities of each or the environment.

During Zimbardo’s experiment , 24 male college students were assigned to be either a prisoner or a guard. The prisoners were held in a makeshift prison inside the basement of Stanford’s psychology department. They went through a standard booking process designed to take away their individuality and make them feel anonymous. Guards were given eight-hour shifts and tasked to treat the prisoners just like they would in real life.

Zimbardo found rather quickly that both the guards and prisoners fully adapted to their roles; in fact, he had to shut down the experiment after six days because it became too dangerous. Zimbardo even admitted he began thinking of himself as a police superintendent rather than a psychologist. The study confirmed that people will conform to the social roles they’re expected to play, especially overly stereotyped ones such as prison guards.

“We realized how ordinary people could be readily transformed from the good Dr. Jekyll to the evil Mr. Hyde,” Zimbardo wrote.

The Asch Conformity Study, 1951

Solomon Asch, a Polish-American social psychologist, was determined to see whether an individual would conform to a group’s decision, even if the individual knew it was incorrect. Conformity is defined by the American Psychological Association as the adjustment of a person’s opinions or thoughts so that they fall closer in line with those of other people or the normative standards of a social group or situation.

In his experiment , Asch selected 50 male college students to participate in a “vision test.” Individuals would have to determine which line on a card was longer. However, the individuals at the center of the experiment did not know that the other people taking the test were actors following scripts, and at times selected the wrong answer on purpose. Asch found that, on average over 12 trials, nearly one-third of the naive participants conformed with the incorrect majority, and only 25 percent never conformed to the incorrect majority. In the control group that featured only the participants and no actors, less than one percent of participants ever chose the wrong answer.

Asch’s experiment showed that people will conform to groups to fit in (normative influence) because of the belief that the group was better informed than the individual. This explains why some people change behaviors or beliefs when in a new group or social setting, even when it goes against past behaviors or beliefs.

The Bobo Doll Experiment, 1961, 1963

Stanford University professor Albert Bandura wanted to put the social learning theory into action. Social learning theory suggests that people can acquire new behaviors “through direct experience or by observing the behavior of others.” Using a Bobo doll , which is a blow-up toy in the shape of a life-size bowling pin, Bandura and his team tested whether children witnessing acts of aggression would copy them.

Bandura and two colleagues selected 36 boys and 36 girls between the ages of 3 and 6 from the Stanford University nursery and split them into three groups of 24. One group watched adults behaving aggressively toward the Bobo doll. In some cases, the adult subjects hit the doll with a hammer or threw it in the air. Another group was shown an adult playing with the Bobo doll in a non-aggressive manner, and the last group was not shown a model at all, just the Bobo doll.

After each session, children were taken to a room with toys and studied to see how their play patterns changed. In a room with aggressive toys (a mallet, dart guns, and a Bobo doll) and non-aggressive toys (a tea set, crayons, and plastic farm animals), Bandura and his colleagues observed that children who watched the aggressive adults were more likely to imitate the aggressive responses.

Unexpectedly, Bandura found that female children acted more physically aggressive after watching a male subject and more verbally aggressive after watching a female subject. The results of the study highlight how children learn behaviors from observing others.

The Learned Helplessness Experiment, 1965

Martin Seligman wanted to research a different angle related to Dr. Watson’s study of classical conditioning. In studying conditioning with dogs, Seligman made an astute observation : the subjects, which had already been conditioned to expect a light electric shock if they heard a bell, would sometimes give up after another negative outcome, rather than searching for the positive outcome.

Under normal circumstances, animals will always try to get away from negative outcomes. When Seligman tested his experiment on animals who hadn’t been previously conditioned, the animals attempted to find a positive outcome. Oppositely, the dogs who had been already conditioned to expect a negative response assumed there would be another negative response waiting for them, even in a different situation.

The conditioned dogs’ behavior became known as learned helplessness, the idea that some subjects won’t try to get out of a negative situation because past experiences have forced them to believe they are helpless. The study’s findings shed light on depression and its symptoms in humans.

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The Milgram Experiment, 1963

In the wake of the horrific atrocities carried out by Nazi Germany during World War II, Stanley Milgram wanted to test the levels of obedience to authority. The Yale University professor wanted to study if people would obey commands, even when it conflicted with the person’s conscience.

Participants of the condensed study , 40 males between the ages of 20 and 50, were split into learners and teachers. Though it seemed random, actors were always chosen as the learners, and unsuspecting participants were always the teachers. A learner was strapped to a chair with electrodes in one room while the experimenter äóñ another actor äóñ and a teacher went into another.

The teacher and learner went over a list of word pairs that the learner was told to memorize. When the learner incorrectly paired a set of words together, the teacher would shock the learner. The teacher believed the shocks ranged from mild all the way to life-threatening. In reality, the learner, who intentionally made mistakes, was not being shocked.

As the voltage of the shocks increased and the teachers became aware of the believed pain caused by them, some refused to continue the experiment. After prodding by the experimenter, 65 percent resumed. From the study, Milgram devised the agency theory , which suggests that people allow others to direct their actions because they believe the authority figure is qualified and will accept responsibility for the outcomes. Milgram’s findings help explain how people can make decisions against their own conscience, such as when participating in a war or genocide.

The Halo Effect Experiment, 1977

University of Michigan professors Richard Nisbett and Timothy Wilson were interested in following up a study from 50 years earlier on a concept known as the halo effect . In the 1920s, American psychologist Edward Thorndike researched a phenomenon in the U.S. military that showed cognitive bias. This is an error in how we think that affects how we perceive people and make judgements and decisions based on those perceptions.

In 1977, Nisbett and Wilson tested the halo effect using 118 college students (62 males, 56 females). Students were divided into two groups and were asked to evaluate a male Belgian teacher who spoke English with a heavy accent. Participants were shown one of two videotaped interviews with the teacher on a television monitor. The first interview showed the teacher interacting cordially with students, and the second interview showed the teacher behaving inhospitably. The subjects were then asked to rate the teacher’s physical appearance, mannerisms, and accent on an eight-point scale from appealing to irritating.

Nisbett and Wilson found that on physical appearance alone, 70 percent of the subjects rated the teacher as appealing when he was being respectful and irritating when he was cold. When the teacher was rude, 80 percent of the subjects rated his accent as irritating, as compared to nearly 50 percent when he was being kind.

The updated study on the halo effect shows that cognitive bias isn’t exclusive to a military environment. Cognitive bias can get in the way of making the correct decision, whether it’s during a job interview or deciding whether to buy a product that’s been endorsed by a celebrity we admire.

How Experiments Have Impacted Psychology Today

Contemporary psychologists have built on the findings of these studies to better understand human behaviors, mental illnesses, and the link between the mind and body. For their contributions to psychology, Watson, Bandura, Nisbett and Zimbardo were all awarded Gold Medals for Life Achievement from the American Psychological Foundation. Become part of the next generation of influential psychologists with King University’s online bachelor’s in psychology . Take advantage of King University’s flexible online schedule and complete the major coursework of your degree in as little as 16 months. Plus, as a psychology major, King University will prepare you for graduate school with original research on student projects as you pursue your goal of being a psychologist.

Experimental Psychology Studies Humans and Animals

Understanding Experimental Psychology

Our personalities, and to some degree our life experiences, are defined by the way we behave. But what influences the way we behave in the first place? How does our behavior shape our experiences throughout our lives? 

Experimental psychologists are interested in exploring theoretical questions, often by creating a hypothesis and then setting out to prove or disprove it through experimentation. They study a wide range of behavioral topics among humans and animals, including sensation, perception, attention, memory, cognition and emotion.

Experimental Psychology Applied

Experimental psychologists use scientific methods to collect data and perform research. Often, their work builds, one study at a time, to a larger finding or conclusion. Some researchers have devoted their entire career to answering one complex research question. 

These psychologists work in a variety of settings, including universities, research centers, government agencies and private businesses. The focus of their research is as varied as the settings in which they work. Often, personal interest and educational background will influence the research questions they choose to explore. 

In a sense, all psychologists can be considered experimental psychologists since research is the foundation of the discipline, and many psychologists split their professional focus among research, patient care, teaching or program administration. Experimental psychologists, however, often devote their full attention to research — its design, execution, analysis and dissemination. 

Those focusing their careers specifically on experimental psychology contribute work across subfields . For example, they use scientific research to provide insights that improve teaching and learning, create safer workplaces and transportation systems, improve substance abuse treatment programs and promote healthy child development.

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How to Conduct a Psychology Experiment

Conducting your first psychology experiment can be a long, complicated, and sometimes intimidating process. It can be especially confusing if you are not quite sure where to begin or which steps to take.

Like other sciences, psychology utilizes the  scientific method  and bases conclusions upon empirical evidence. When conducting an experiment, it is important to follow the seven basic steps of the scientific method:

• Ask a testable question
• Define your variables
• Conduct background research
• Design your experiment
• Perform the experiment
• Collect and analyze the data
• Draw conclusions
• Share the results with the scientific community

At a Glance

It's important to know the steps of the scientific method if you are conducting an experiment in psychology or other fields. The processes encompasses finding a problem you want to explore, learning what has already been discovered about the topic, determining your variables, and finally designing and performing your experiment. But the process doesn't end there! Once you've collected your data, it's time to analyze the numbers, determine what they mean, and share what you've found.

Find a Research Problem or Question

Picking a research problem can be one of the most challenging steps when you are conducting an experiment. After all, there are so many different topics you might choose to investigate.

Are you stuck for an idea? Consider some of the following:

Investigate a Commonly Held Belief

Folk knowledge is a good source of questions that can serve as the basis for psychological research. For example, many people believe that staying up all night to cram for a big exam can actually hurt test performance.

You could conduct a study to compare the test scores of students who stayed up all night with the scores of students who got a full night's sleep before the exam.

Review Psychology Literature

Published studies are a great source of unanswered research questions. In many cases, the authors will even note the need for further research. Find a published study that you find intriguing, and then come up with some questions that require further exploration.

Think About Everyday Problems

There are many practical applications for psychology research. Explore various problems that you or others face each day, and then consider how you could research potential solutions. For example, you might investigate different memorization strategies to determine which methods are most effective.

Define Your Variables

Variables are anything that might impact the outcome of your study. An operational definition describes exactly what the variables are and how they are measured within the context of your study.

For example, if you were doing a study on the impact of sleep deprivation on driving performance, you would need to operationally define sleep deprivation and driving performance .

An operational definition refers to a precise way that an abstract concept will be measured. For example, you cannot directly observe and measure something like test anxiety . You can, however, use an anxiety scale and assign values based on how many anxiety symptoms a person is experiencing. 

In this example, you might define sleep deprivation as getting less than seven hours of sleep at night. You might define driving performance as how well a participant does on a driving test.

What is the purpose of operationally defining variables? The main purpose is control. By understanding what you are measuring, you can control for it by holding the variable constant between all groups or manipulating it as an independent variable .

Develop a Hypothesis

The next step is to develop a testable hypothesis that predicts how the operationally defined variables are related. In the recent example, the hypothesis might be: "Students who are sleep-deprived will perform worse than students who are not sleep-deprived on a test of driving performance."

Null Hypothesis

In order to determine if the results of the study are significant, it is essential to also have a null hypothesis. The null hypothesis is the prediction that one variable will have no association to the other variable.

In other words, the null hypothesis assumes that there will be no difference in the effects of the two treatments in our experimental and control groups .

The null hypothesis is assumed to be valid unless contradicted by the results. The experimenters can either reject the null hypothesis in favor of the alternative hypothesis or not reject the null hypothesis.

It is important to remember that not rejecting the null hypothesis does not mean that you are accepting the null hypothesis. To say that you are accepting the null hypothesis is to suggest that something is true simply because you did not find any evidence against it. This represents a logical fallacy that should be avoided in scientific research.  

Conduct Background Research

Once you have developed a testable hypothesis, it is important to spend some time doing some background research. What do researchers already know about your topic? What questions remain unanswered?

You can learn about previous research on your topic by exploring books, journal articles, online databases, newspapers, and websites devoted to your subject.

Reading previous research helps you gain a better understanding of what you will encounter when conducting an experiment. Understanding the background of your topic provides a better basis for your own hypothesis.

After conducting a thorough review of the literature, you might choose to alter your own hypothesis. Background research also allows you to explain why you chose to investigate your particular hypothesis and articulate why the topic merits further exploration.

As you research the history of your topic, take careful notes and create a working bibliography of your sources. This information will be valuable when you begin to write up your experiment results.

Select an Experimental Design

After conducting background research and finalizing your hypothesis, your next step is to develop an experimental design. There are three basic types of designs that you might utilize. Each has its own strengths and weaknesses:

Pre-Experimental Design

A single group of participants is studied, and there is no comparison between a treatment group and a control group. Examples of pre-experimental designs include case studies (one group is given a treatment and the results are measured) and pre-test/post-test studies (one group is tested, given a treatment, and then retested).

Quasi-Experimental Design

This type of experimental design does include a control group but does not include randomization. This type of design is often used if it is not feasible or ethical to perform a randomized controlled trial.

True Experimental Design

A true experimental design, also known as a randomized controlled trial, includes both of the elements that pre-experimental designs and quasi-experimental designs lack—control groups and random assignment to groups.

Standardize Your Procedures

In order to arrive at legitimate conclusions, it is essential to compare apples to apples.

Each participant in each group must receive the same treatment under the same conditions.

For example, in our hypothetical study on the effects of sleep deprivation on driving performance, the driving test must be administered to each participant in the same way. The driving course must be the same, the obstacles faced must be the same, and the time given must be the same.

Choose Your Participants

In addition to making sure that the testing conditions are standardized, it is also essential to ensure that your pool of participants is the same.

If the individuals in your control group (those who are not sleep deprived) all happen to be amateur race car drivers while your experimental group (those that are sleep deprived) are all people who just recently earned their driver's licenses, your experiment will lack standardization.

When choosing subjects, there are some different techniques you can use.

Simple Random Sample

In a simple random sample, the participants are randomly selected from a group. A simple random sample can be used to represent the entire population from which the representative sample is drawn.

Drawing a simple random sample can be helpful when you don't know a lot about the characteristics of the population.

Stratified Random Sample

Participants must be randomly selected from different subsets of the population. These subsets might include characteristics such as geographic location, age, sex, race, or socioeconomic status.

Stratified random samples are more complex to carry out. However, you might opt for this method if there are key characteristics about the population that you want to explore in your research.

Conduct Tests and Collect Data

After you have selected participants, the next steps are to conduct your tests and collect the data. Before doing any testing, however, there are a few important concerns that need to be addressed.

Address Ethical Concerns

First, you need to be sure that your testing procedures are ethical . Generally, you will need to gain permission to conduct any type of testing with human participants by submitting the details of your experiment to your school's Institutional Review Board (IRB), sometimes referred to as the Human Subjects Committee.

Obtain Informed Consent

After you have gained approval from your institution's IRB, you will need to present informed consent forms to each participant. This form offers information on the study, the data that will be gathered, and how the results will be used. The form also gives participants the option to withdraw from the study at any point in time.

Once this step has been completed, you can begin administering your testing procedures and collecting the data.

Analyze the Results

After collecting your data, it is time to analyze the results of your experiment. Researchers use statistics to determine if the results of the study support the original hypothesis and if the results are statistically significant.

Statistical significance means that the study's results are unlikely to have occurred simply by chance.

The types of statistical methods you use to analyze your data depend largely on the type of data that you collected. If you are using a random sample of a larger population, you will need to utilize inferential statistics.

These statistical methods make inferences about how the results relate to the population at large.

Because you are making inferences based on a sample, it has to be assumed that there will be a certain margin of error. This refers to the amount of error in your results. A large margin of error means that there will be less confidence in your results, while a small margin of error means that you are more confident that your results are an accurate reflection of what exists in that population.

Share Your Results After Conducting an Experiment

Your final task in conducting an experiment is to communicate your results. By sharing your experiment with the scientific community, you are contributing to the knowledge base on that particular topic.

One of the most common ways to share research results is to publish the study in a peer-reviewed professional journal. Other methods include sharing results at conferences, in book chapters, or academic presentations.

In your case, it is likely that your class instructor will expect a formal write-up of your experiment in the same format required in a professional journal article or lab report :

• Introduction
• Tables and figures

What This Means For You

Designing and conducting a psychology experiment can be quite intimidating, but breaking the process down step-by-step can help. No matter what type of experiment you decide to perform, always check with your instructor and your school's institutional review board for permission before you begin.

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By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."