conditioned stimulus in pavlov's dog experiment

Warning: The NCBI web site requires JavaScript to function. more...

An official website of the United States government

The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• Browse Titles

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

StatPearls [Internet].

Classical conditioning.

Ibraheem Rehman ; Navid Mahabadi ; Terrence Sanvictores ; Chaudhry I. Rehman .

Affiliations

Last Update: August 14, 2023 .

• Introduction

Learning is the process by which new knowledge, behaviors, attitudes, and ideas are acquired. Learning can occur through both unconscious and conscious pathways. Classical conditioning is one of those unconscious learning methods and is the most straightforward way in which humans can learn. Classical conditioning is the process in which an automatic, conditioned response is paired with specific stimuli. Although Edwin Twitmyer published findings pertaining to classical conditioning one year earlier, the best-known and most thorough work on classical conditioning is accredited to Ivan Pavlov, a Russian physiologist born in the mid-1800s. Pavlov had such a great impact on the study of classical conditioning that it is often referred to as Pavlovian conditioning. [1] [2] [3]

Pavlov’s Experiment

Classical conditioning was stumbled upon by accident. Pavlov was conducting research on the digestion of dogs when he noticed that the dogs’ physical reactions to food subtly changed over time. At first, the dogs would only salivate when the food was placed in front of them. However, later they salivated slightly before their food arrived. Pavlov realized that they were salivating at the noises that were consistently present before the food arrived; for example, the sound of a food cart is approaching.

To test his theory, Pavlov set up an experiment in which he rang a bell shortly before presenting food to the dogs. At first, the dogs elicited no response to the bells. However, eventually, the dogs began to salivate at the sound of the bell alone.

To understand classical conditioning, it is essential to be familiar with the following terms. A neutral stimulus is a stimulus that at first elicits no response. Pavlov introduced the ringing of the bell as a neutral stimulus. An unconditioned stimulus is a stimulus that leads to an automatic response. In Pavlov’s experiment, the food was the unconditioned stimulus. An unconditioned response is an automatic response to a stimulus. The dogs salivating for food is the unconditioned response in Pavlov’s experiment. A conditioned stimulus is a stimulus that can eventually trigger a conditioned response. In the described experiment, the conditioned stimulus was the ringing of the bell, and the conditioned response was salivation.

It is important to note that the neutral stimulus becomes the conditioned stimulus. Furthermore, it is important to realize that the unconditioned response and the conditioned response are the same except for which stimulus they are elicited by. In this case, salivation was the response, but the unconditioned response was triggered by food, whereas the conditioned response was triggered by the bell which indicated the coming of food.

Pavlov recorded several phenomena associated with classical conditioning. He found that the rate of acquisition, the initial stages of learning, depended on the noticeability of the stimulus and the time in between the introduction of the neutral stimulus and the unconditioned stimulus. In Pavlov’s experiment, this would translate to the time in between the bell ringing and the presentation of food. Second, Pavlov observed that the conditioned response was vulnerable to extinction. If the conditioned stimulus is continuously supplied in the absence of the unconditioned stimulus, then the conditioned response becomes weaker and weaker until it disappears. In Pavlov’s experiment, this would translate to Pavlov ringing the bell without giving food to the dogs. Eventually, the dogs would stop salivating at the sound of the bell. However, spontaneous recovery was also observed. Even if a substantial amount of time had passed, the conditioned response would easily recover if the neutral stimulus and the unconditioned stimulus were paired again. Lastly, he found that stimulus generalization and stimulus discrimination can occur. Stimulus generalization occurs when the dog can respond to stimuli that are similar to the conditioned stimulus. For example, if Pavlov’s dogs salivated at the sound of another ringing sound such as a cell phone ringing, that would be stimulus generalization. Stimulus discrimination, on the other hand, is being able to differentiate between similar stimuli and respond only to the correct stimuli. [4] [5] [6] [7]

• Issues of Concern

People can use classical conditioning to exploit others for their gain. A prominent example of this occurs in advertising. The advertiser generally attempts to get consumers to associate their product with a particular response or feeling so they are more likely to buy the product. Advertisers can use music or mouth-watering food in their ads to create an association with their product. These types of associations can lead to increased spending as well as poor eating habits especially if the product is unhealthy food. 

• Clinical Significance

Most psychologists now agree that classical conditioning is a basic form of learning. Furthermore, it is well-known that Pavlovian principles can influence human health, emotion, motivation, and therapy of psychological disorders. There are many clinically related uses of classical conditioning. For example, former drug users often have a craving when they are in a drug-related environment or around people that they associate with previous highs. Drug counselors often advise these people to stay away from settings that could trigger a desire to take drugs again. Also, it has been proven that classical conditioning can even affect the human immune system. When a particular taste accompanies a drug that influences an immune response, sometimes the taste itself can induce the immune response at a later time. Another example can be found in the overcoming of phobias. One patient, who had feared getting into an elevator for 30 years, forced herself to enter 20 elevators a day. After 10 days, her fear had almost completely vanished.

O.H Mowrer discovered that certain behaviors can be reconditioned when he successfully developed a therapy for bed-wetters. In his therapy, the child would sleep on a liquid-sensitive pad connected to an alarm. Once moisture was detected, the alarm would go off. After repetition, bladder relaxation became associated with waking up and 75% of the time, frequent bed-wetters were healed and longer wet the bed while they slept.

Another example of an effective therapy that is used to cure phobias is counterconditioning, which pairs the trigger stimulus with a response that is contrary to fear. Two counterconditioning techniques that have been proven to be effective are exposure therapy and aversive therapy. In general, exposure therapies are therapies that expose people to what scares them. Two types of exposure therapies are systematic desensitization and virtual reality exposure therapy. In systematic desensitization, a pleasant, relaxed state is associated with increasing anxiety-triggering stimuli. This therapy is common in the treatment of phobias. Virtual reality exposure follows the same concept as general exposure therapy but uses virtual reality to do instead of real-life situations. Aversive conditioning has the goal of substituting a negative response for a positive response to a harmful stimulus. This is essentially the reverse of systematic desensitization in which a positive response is replaced with a negative response to a harmless stimulus. One common example of aversive conditioning is mixing alcohol with an extremely bitter taste or lacing fingernails with something that causes severe nausea. The problem with this therapy is that patients can differentiate between situations inside and outside of the psychiatrist’s office. An alcoholic understands that if he drinks alcohol, it will normally not have that bitter taste. For this reason, a combination of conditioning therapies is the best approach to treat certain issues. [8] [9]

• Other Issues

A combination of both behavior modification therapy with medications can lead to better clinical outcomes than if either option is used alone. Some studies show enhanced outcomes when certain drugs are used in the psychological treatment of anxiety disorders and even post-traumatic stress disorders. Despite the clinical efficacy of these studies, it should be noted that each individual can have a different treatment plan that is optimal to only them. Some people might respond better to only therapy or medications rather than a combination of both. Furthermore, combination treatments can be more of a "mix and match" treatment where two patients can have similar amounts of treatment success but use different medications and therapy options. [10] [11] [12]

• Enhancing Healthcare Team Outcomes

Classical conditioning concepts are integrated into the design of health-related interventions (i.e. modeling, reinforcement, expectancies, and cues to action). Cohesiveness and consistency of the patient/ interprofessional team implementing these types of interventions are important factors for success. The interprofessional healthcare team consists of diagnosticians, medication experts, prescribers, and other members who tend to the everyday needs of the patient. Cohesiveness and communication become especially important for the extinguishing of addictive behaviors such as drug use, smoking, or drinking alcohol. Since relapse is always a possibility, proper protocols should be in place to help re-extinguish the behavior if necessary. However, these protocols mainly depend on the patient's honesty and willingness to seek out help. Additionally, the interprofessional team can increase conditioning success by involving the patient's friends and family. They not only provide emotional support for the patient but can also provide updates to the interprofessional team when needed. [13] [14]

• Review Questions
• Access free multiple choice questions on this topic.
• Comment on this article.

Disclosure: Ibraheem Rehman declares no relevant financial relationships with ineligible companies.

Disclosure: Navid Mahabadi declares no relevant financial relationships with ineligible companies.

Disclosure: Terrence Sanvictores declares no relevant financial relationships with ineligible companies.

Disclosure: Chaudhry Rehman declares no relevant financial relationships with ineligible companies.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

• Cite this Page Rehman I, Mahabadi N, Sanvictores T, et al. Classical Conditioning. [Updated 2023 Aug 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

In this Page

Bulk download.

• Bulk download StatPearls data from FTP

Related information

• PMC PubMed Central citations
• PubMed Links to PubMed

Similar articles in PubMed

• Review Chronic Recording During Learning. [Methods for Neural Ensemble Re...] Review Chronic Recording During Learning. Sandler AJ. Methods for Neural Ensemble Recordings. 2008
• Eponymy, obscurity, Twitmyer, and Pavlov. [J Hist Behav Sci. 1982] Eponymy, obscurity, Twitmyer, and Pavlov. Coon DJ. J Hist Behav Sci. 1982 Jul; 18(3):255-62.
• Pavlov's position toward Konorski and Miller's distinction between Pavlovian and motor conditioning paradigms. [Integr Physiol Behav Sci. 1996] Pavlov's position toward Konorski and Miller's distinction between Pavlovian and motor conditioning paradigms. Windholz G, Wyrwicka W. Integr Physiol Behav Sci. 1996 Oct-Dec; 31(4):338-49.
• Signalization and stimulus-substitution in Pavlov's theory of conditioning. [Span J Psychol. 2003] Signalization and stimulus-substitution in Pavlov's theory of conditioning. García-Hoz V. Span J Psychol. 2003 Nov; 6(2):168-76.
• Review Pavlov as a psychologist. A reappraisal. [Pavlov J Biol Sci. 1987] Review Pavlov as a psychologist. A reappraisal. Windholz G. Pavlov J Biol Sci. 1987 Jul-Sep; 22(3):103-12.

Recent Activity

• Classical Conditioning - StatPearls Classical Conditioning - StatPearls

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

Connect with NLM

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894

Web Policies FOIA HHS Vulnerability Disclosure

Help Accessibility Careers

Pavlov’s Dog: The Psychology Experiment That Changed Everything

Pavlov’s Dog is a well-known experiment in psychology that has been taught for decades. Ivan Pavlov , a Russian physiologist, discovered classical conditioning through his experiments with dogs. He found that dogs could be trained to associate a sound with food, causing them to salivate at the sound alone.

The experiment began with Pavlov ringing a bell every time he fed his dogs. After a while, the dogs began to associate the sound of the bell with food and would salivate at the sound alone, even if no food was present. This became known as a conditioned response, where a previously neutral stimulus (the bell) became associated with a natural response (salivating).

The experiment has been used to explain many psychological phenomena, including addiction, phobias, and anxiety. It has also been applied in therapy, where patients can learn to associate positive experiences with previously negative stimuli. The Pavlov’s Dog experiment is a crucial part of psychology’s history and continues to be studied today.

Pavlov’s Life and Career

Ivan Pavlov was a Russian physiologist who lived from 1849 to 1936. He is best known for his work in classical conditioning, a type of learning that occurs when a neutral stimulus is consistently paired with a stimulus that elicits a response. Pavlov was born in Ryazan, Russia, and studied at the University of St. Petersburg, where he received his doctorate in 1879.

Pavlov’s early research focused on the digestive system, and he discovered that the secretion of gastric juice was not a passive process but rather a response to stimuli. This led him to develop the concept of the conditioned reflex, which he explored in detail in his famous experiments with dogs.

In these experiments, Pavlov trained dogs to associate the sound of a bell with food presentation. Over time, the dogs began to salivate at the sound of the bell, even when no food was present. This demonstrated that a neutral stimulus (the bell) could become associated with a natural response (salivation) through repeated pairings with a stimulus that elicits that response (food).

Pavlov’s work had a profound impact on the field of psychology, and his ideas continue to influence research today. He was awarded the Nobel Prize in Physiology or Medicine in 1904 for his work on the physiology of digestion. Still, his legacy is best remembered for his contributions to the study of learning and behavior.

Classical Conditioning

Classical conditioning is a type of learning that occurs when a neutral stimulus is repeatedly paired with a stimulus that naturally elicits a response. Over time, the neutral stimulus becomes associated with the natural stimulus and begins to produce the same response. Russian physiologist Ivan Pavlov first studied this type of learning in the late 1800s.

One of the most famous examples of classical conditioning is Pavlov’s experiment with dogs. In this experiment, Pavlov rang a bell every time he fed the dogs. Eventually, the dogs began to salivate at the sound of the bell, even when no food was present. The sound of the bell had become associated with the food, and the dogs had learned to associate the two stimuli.

Classical conditioning can be used to explain a variety of behaviors and responses. For example, a person who has been in a car accident may develop a fear of driving. The sound of screeching tires or the sight of a car may become associated with the traumatic experience, causing the person to feel anxious or fearful when driving.

Classical conditioning can also be used to treat certain types of phobias and anxiety disorders. By gradually exposing a person to the feared stimulus in a safe and controlled environment, the person can learn to associate the stimulus with safety and relaxation rather than fear and anxiety.

Classical conditioning is a powerful tool for understanding how we learn and respond to environmental stimuli. By understanding the principles of classical conditioning, we can better understand our behaviors and emotions, as well as those of others around us.

Pavlov’s Experiments

Pavlov’s experiments with dogs revolutionized the field of psychology and laid the foundation for the study of classical conditioning. In this section, we will explore two aspects of his experiments: salivating dogs and conditioned responses.

Salivating Dogs

Pavlov observed that dogs would salivate when presented with food. However, he also noticed that the dogs would start salivating before the food was presented. This led him to hypothesize that the dogs were responding not just to the food but to other associated stimuli, such as the sound of the food being prepared or the sight of the person who fed them.

To test his hypothesis, Pavlov began a series of experiments where he would ring a bell before presenting the dogs with food. After a few repetitions, the dogs began to salivate at the sound of the bell alone, even when no food was present. This demonstrated that the dogs had learned to associate the sound of the bell with the presence of food and were responding accordingly.

Conditioned Response

Pavlov’s experiments with dogs led to the discovery of the conditioned response, the learned response to a previously neutral stimulus. In the case of Pavlov’s dogs, the sound of the bell was originally a neutral stimulus. Still, it became associated with food and, therefore, elicited a response (salivation) from the dogs.

The conditioned response is an essential concept in psychology, as it helps to explain how we learn to respond to various stimuli in our environment. For example, if we have a positive experience with a particular food, we may develop a conditioned response to the sight or smell of that food, even if we are not hungry.

Pavlov’s experiments with dogs were groundbreaking in psychology and led to the discovery of classical conditioning and the conditioned response. By demonstrating that animals (and humans) can learn to respond to previously neutral stimuli, Pavlov paved the way for further research into the mechanisms of learning and behavior.

Significance in Psychology

Pavlov’s dog experiment has been a significant discovery in psychology. It has paved the way for developing various theories and has been instrumental in understanding human behavior. In this section, we will discuss the significance of Pavlov’s dog experiment in the context of behaviorism and learning theories.

Behaviorism

Pavlov’s dog experiment has been a cornerstone in the development of behaviorism. Behaviorism is a school of thought in psychology that emphasizes the importance of observable behavior rather than internal mental states. Pavlov’s experiment demonstrated how a stimulus-response connection could be formed through conditioning. This concept has been used to explain various behaviors, such as phobias and addictions.

Learning Theories

Pavlov’s dog experiment has also been significant in developing learning theories . Learning theories are concerned with how people acquire new knowledge and skills. Pavlov’s experiment demonstrated how classical conditioning could teach animals new behaviors. This concept has been used to explain various learning phenomena, such as the acquisition of language and the development of social skills.

In conclusion, Pavlov’s dog experiment has been a significant discovery in psychology. It has been instrumental in the development of behaviorism and learning theories. By understanding the principles of classical conditioning, we can better understand human behavior and how we learn new skills and behaviors.

Implications in Modern Psychology

Pavlov’s dog experiments have had a significant impact on modern psychology. His theory of classical conditioning has become a cornerstone of behaviorism, a school of thought that dominated psychology in the early 20th century. Today, it continues to influence psychologists and researchers in various fields.

One of the most significant implications of Pavlov’s work is the understanding of how learning takes place. His experiments showed that animals, including humans, can learn through association. This concept has been applied in many areas of modern psychology, including education, advertising, and even politics.

For example, in education, classical conditioning can improve students’ learning by associating positive experiences with specific subjects or activities. In advertising, classical conditioning can create positive associations between a product and a particular emotion or experience, influencing consumers’ purchasing decisions.

Moreover, Pavlov’s work has also contributed to developing other learning theories, such as operant conditioning, which focuses on the consequences of behavior rather than the stimuli that precede it. These theories have been used to explain various human behaviors, from addiction to language acquisition.

Pavlov’s dog experiments have had a lasting impact on modern psychology. His theory of classical conditioning has contributed to our understanding of how learning takes place and has been applied in various fields, from education to advertising. His work has also influenced the development of other learning theories, making it a crucial part of studying human behavior.

Criticism and Controversies

While Pavlov’s experiments have been foundational in psychology, they have also been subject to criticism and controversy. Here are a few examples:

• Animal cruelty:  Some critics argue that Pavlov’s experiments on dogs were cruel and unethical. The dogs were often subjected to painful surgeries and kept in small cages for long periods. While these practices were common in the early 20th century, they would not be acceptable by today’s ethical standards.
• Oversimplification of behavior:  Pavlov’s experiments focused on classical conditioning, which suggests that behavior is determined solely by external stimuli. However, this oversimplifies the complex nature of human behavior, which is influenced by various factors, including genetics, environment, and personal experience.
• Limited generalizability:  Pavlov’s experiments were conducted on dogs, which may not accurately reflect human behavior. While some of the principles of classical conditioning may apply to humans, it is essential to recognize that there are also significant differences between species.
• Misinterpretation of results:  Pavlov’s work has been subject to misinterpretation over the years. For example, many people believe that Pavlov’s dogs learned to salivate at the sound of a bell because they associated it with food. However, this is only partially accurate. The dogs learned to associate the sound of the bell with the experimenter’s presence, who would then provide the food.

Frequently Asked Questions

What were the basic features of classical conditioning discovered by pavlov.

Classical conditioning is a type of learning in which a neutral stimulus becomes associated with a meaningful stimulus, resulting in a behavioral response. Pavlov discovered that when a neutral stimulus (such as a bell) was repeatedly paired with a meaningful stimulus (such as food), the neutral stimulus alone could elicit the same response (such as salivation) as the meaningful stimulus.

What was the purpose of Pavlov’s dog experiment?

Pavlov’s dog experiment was designed to study the process of classical conditioning. He wanted to understand how dogs learn to associate a neutral stimulus (such as a bell) with a meaningful stimulus (such as food) and how this association leads to a behavioral response (such as salivation).

How did Pavlov’s experiments contribute to the development of psychology?

Pavlov’s experiments were groundbreaking in the field of psychology. They provided evidence for the concept of classical conditioning, which has since been used to explain a wide range of human and animal behaviors. Pavlov’s work also paved the way for the development of behaviorism, a school of psychology that emphasizes the importance of observable behavior in understanding human and animal psychology.

What is the Pavlovian response and how does it work?

The Pavlovian response is a learned response to a previously neutral stimulus. It works by pairing the neutral stimulus with a meaningful stimulus, which leads to the formation of an association between the two. Once the association is formed, the neutral stimulus alone can elicit the same response as the meaningful stimulus.

How is Pavlovian conditioning used in dog training?

Pavlovian conditioning is often used in dog training to teach dogs new behaviors or to modify existing ones. For example, a trainer might use a clicker (a neutral stimulus) to signal to a dog that it has performed a desired behavior (a meaningful stimulus), and then reward the dog with a treat. Over time, the dog will learn to associate the clicker with the reward and will perform the desired behavior without the need for a treat.

What is the Pavlovian response in humans and how is it studied?

The Pavlovian response in humans is similar to that in dogs: it involves the formation of an association between a neutral stimulus and a meaningful stimulus, resulting in a learned response. This response has been studied in a variety of contexts, including addiction, phobias, and taste aversions. Researchers use a variety of methods to study the Pavlovian response in humans, including brain imaging techniques and behavioral experiments.

Leave a Comment Cancel reply

Save my name, email, and website in this browser for the next time I comment.

Learn More Psychology

• Behavioral Psychology

Pavlov's Dogs and Classical Conditioning

How pavlov's experiments with dogs demonstrated that our behavior can be changed using conditioning..

Permalink Print   |  

• Biological Psychology
• Body Language Interpretation
• Cognitive Psychology
• Developmental Psychology
• Dream Interpretation
• Freudian Psychology
• Memory & Memory Techniques
• Role Playing: Stanford Prison Experiment
• Authoritarian Personality
• Memory: Levels of Processing
• Cold Reading: Psychology of Fortune Telling
• Stages of Sleep
• Personality Psychology
• Why Do We Forget?
• Psychology of Influence
• Stress in Psychology
• Body Language: How to Spot a Liar
• Be a Better Communicator
• Eye Reading: Body Language
• Motivation: Maslow's Hierarchy of Needs
• How to Interpret your Dreams Guide
• How to Remember Your Dreams
• Interpreting Your Dreams
• Superstition in Pigeons
• Altruism in Animals and Humans
• Stimulus-Response Theory
• Conditioned Behavior
• Synesthesia: Mixing the Senses
• Freudian Personality Type Test
• ... and much more
• Unlimited access to analysis of groundbreaking research and studies
• 17+ psychology guides : develop your understanding of the mind
• Self Help Audio : MP3 sessions to stream or download

Best Digital Psychology Magazine - UK

Best online psychology theory resource, continue reading.

• Coon, D.J. (1982). Eponymy, obscurity, Twitmyer, and Pavlov. Journal of the History of Behavioral Science . 18 (3). 255-62.
• Pavlov, I.P. (1927). Conditioned Reflexes: An investigation of the physiological activity of the cerebral cortex. Retrieved from http://psychclassics.yorku.ca/Pavlov/ .
• Craik, F.I.M. and Lockhart, R.S. (1972). Levels of Processing: A Framework for Memory Research. Journal of Verbal Learning and Visual Behavior . 11 (6). 671-684.
• Carr, H. and Freeman A. (1919). Time relationships in the formation of associations. Psychology Review . 26 (6). 335-353.
• Pavlov, I.P. (1927). Conditioned Reflexes: An investigation of the physiological activity of the cerebral cortex. Retrieved from http://psychclassics.yorku.ca/Pavlov/lecture6.htm .
• Kirkpatrick, K and Church, R.M. (2003). Tracking of the expected time to reinforcement in temporal conditioning processes. Learning & Behavior . 31 (1). 3-21.
• Meulders A, Vandebroek, N. Vervliet, B. and Vlaeyen, J.W.S. (2013). Generalization Gradients in Cued and Contextual Pain-Related Fear: An Experimental Study in Health Participants. Frontiers in Human Neuroscience , 7 (345). 1-12.
• Watson, J.B. and Rayner, R. (1920). Conditioned Emotional Reactions. Journal of Experimental Psychology . 3 (1). 1-14.
• Watson, J.B. (1913). Psychology as the Behaviorist Views It. Psychological Review . (Watson, 1913). 20 . 158-177.

Which Archetype Are You?

Are You Angry?

Windows to the Soul

Are You Stressed?

Attachment & Relationships

Memory Like A Goldfish?

31 Defense Mechanisms

Slave To Your Role?

Are You Fixated?

Interpret Your Dreams

How to Read Body Language

How to Beat Stress and Succeed in Exams

Psychology Topics

Learn psychology.

• Access 2,200+ insightful pages of psychology explanations & theories
• Insights into the way we think and behave
• Body Language & Dream Interpretation guides
• Self hypnosis MP3 downloads and more
• Behavioral Approach
• Eye Reading
• Stress Test
• Cognitive Approach
• Fight-or-Flight Response
• Neuroticism Test

© 2024 Psychologist World. Home About Contact Us Terms of Use Privacy & Cookies Hypnosis Scripts Sign Up

Conditioned Stimulus In Classical Conditioning

Julia Simkus

Editor at Simply Psychology

BA (Hons) Psychology, Princeton University

Julia Simkus is a graduate of Princeton University with a Bachelor of Arts in Psychology. She is currently studying for a Master's Degree in Counseling for Mental Health and Wellness in September 2023. Julia's research has been published in peer reviewed journals.

Learn about our Editorial Process

Saul McLeod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

Using the terminology of the classical conditioning paradigm , the conditioned stimulus (CS) is a learned stimulus that can eventually trigger a conditioned response. For example, the sound of a bell is the conditioned stimulus in Pavlov’s experiment, and the dogs salivating would be the conditioned response.

In classical conditioning, a person or animal learns to associate the conditioned stimulus (previously a neutral stimulus) with the unconditioned stimulus that naturally produces an automatic behavior (the unconditioned response).

Therefore, a conditioned stimulus makes an organism react to something because it is associated with something else, which is usually a reflective stimuli eliciting an automatic response.

The best-known and most thorough work on classical conditioning was discovered by Ivan Pavlov in the early 1900s in his experiments on the digestive response of dogs. Pavlov had such a great impact on the study of classical conditioning that it is often referred to as Pavlovian conditioning.

In classical conditioning, the conditioned stimulus begins as a neutral stimulus that eventually comes to automatically trigger a conditioned response after becoming associated with an unconditioned stimulus. After the neutral stimulus becomes associated with the unconditioned stimulus, it becomes the conditioned stimulus.

So, if you pair a neutral stimulus (NS) with an unconditioned stimulus (US) that already triggers an unconditioned response (UR) that neutral stimulus will become a conditioned stimulus (CS), triggering a conditioned response (CR) similar to the original unconditioned response.

For example, let’s say you experience horrible food poisoning the first time you eat sushi. While sushi was originally a neutral stimulus, it becomes a conditioned stimulus through its association with being sick (the unconditioned stimulus). As a result, you might begin to feel sick from just the smell of sushi or the sight of raw fish.

What is an example of a conditioned stimulus?

Pavlovs dogs experiment.

Ivan Pavlov was the first person to discover the process of classical conditioning. When conducting research on the digestion of dogs, Pavlov noticed that the dogs’ physical reactions to food changed over time.

While at first, the dogs would only salivate when the food was placed in front of them, they eventually began to salivate slightly before their food arrived.

He realized that the dogs were not salivating to the smell or sight of the food in front of them but rather the noises and sites that were consistently present before the food even arrived.

To test his theory further, Pavlov would ring a bell shortly before presenting food to the dogs. At first, this elicited no response from the dogs, but eventually, the dogs learned to associate the sound of the bell with the presentation of the food and they would begin to salivate at the sound of the bell alone.

As mentioned earlier, a conditioned stimulus is a stimulus that can eventually trigger a conditioned response.

In this example, the sound of the bell became the conditioned stimulus that triggered the conditioned response of salivation. It is important to note that the neutral stimulus becomes the conditioned stimulus.

Little Albert (Watson & Raynor) Experiment

Behaviorist John B. Watson and graduate student Rosalie Rayner were the first psychologists to apply the principles of classical conditioning to human behavior by showing that emotional reactions could be classically conditioned in people.

Their experiment, known as the case of Little Albert , involved conditioning a phobia in an emotionally stable child.

When Albert was just 9 months old, Watson and Rayner exposed him to a series of stimuli, including a white rat, burning newspapers, a monkey, and masks.

At first, Alert showed no fear of any of the stimuli.

However, the next time Albert was exposed to each stimuli, Watson would make a loud noise by hitting a metal pipe with a hammer.

After repeatedly pairing one of the stimuli, the white rat for example, with the loud noise, Albert would begin to expect a loud noise whenever he saw the white rate.

Eventually, Albert would begin to cry from simply seeing the rat. In other words, he was classically conditioned to experience fear at the sight of the rat.

In this example, the white rat began as a neutral stimulus, but it eventually became the conditioned stimulus after repeatedly being paired with the loud noise (the unconditioned stimulus).

Advertising

Classical conditioning is an effective tool in marketing and advertising. The idea is to create an advertisement that has positive features such as catchy music, bright colors, cute babies, attractive models, or funny spokespeople so that the ad will create an enjoyable response in the person exposed to it.

Thus, when the consumer sees a particular product online or in the store, he/she should experience this positive feeling and be more likely to purchase the product.

In this example, the advertisement serves as the unconditioned stimulus (US), and the enjoyment from watching the advertisement serves as the unconditioned response (UR).

Because the product being advertised is mentioned in the advertisement, it becomes associated with the US, and then becomes the conditioned stimulus (CS).

For example, in one study, Gorn (1982) showed research participants pictures of different writing pens of different colors, but paired one of the pens with pleasant music and the other with unpleasant music. When given a choice as a free gift, more people chose the pen color associated with the pleasant music.

1. What is a conditioned stimulus?

In classical conditioning, a conditioned stimulus is a previously neutral stimulus that, after being repeatedly associated with an unconditioned stimulus, evokes a conditioned response.

2. Is fear a conditioned response?

Yes, fear can be a conditioned response. Fear conditioning is a behavioral paradigm where organisms learn to predict aversive events or fear new stimuli.

This can be done by pairing a neutral stimulus (e.g., a tone) with an aversive stimulus (e.g. an electrical shock). Eventually, the neutral stimulus alone would be able to elicit the state of fear.

3. What is the difference between the conditioned stimulus and the unconditioned stimulus?

The conditioned stimulus begins as a neutral stimulus that eventually comes to automatically trigger a conditioned response after becoming associated with an  unconditioned stimulus .

While a conditioned stimulus produces a learned response to the previously neutral stimulus, the unconditioned stimulus naturally and automatically triggers a response without any previous learning. There is no necessity to learn to respond to an unconditioned stimulus.

4. What is the difference between the conditioned stimulus and the neutral stimulus?

A neutral stimulus is a stimulus that does not produce an automatic response. But, in classical conditioning, the neutral stimulus will become a conditioned stimulus when consistently paired with an unconditioned stimulus.

For example, in Pavlov’s experiment, the sound of the bell began as a neutral stimulus but eventually became the conditioned stimulus that triggered the conditioned response of salivation.

5. How does a neutral stimulus become a conditioned stimulus?

A neutral stimulus becomes a conditioned stimulus when used together with an unconditioned stimulus.

With repeated exposures to both the neutral stimulus and the unconditioned stimulus at the same time, the neutral stimulus will begin to elicit a response known as a conditioned response.

Once the neutral stimulus elicits this conditioned response, the neutral stimulus becomes known as a conditioned stimulus.

6. What is the difference between the conditioned stimulus and the discriminative stimulus?

A discriminative stimulus refers to something, like a person or an event, that precedes a behavioral response. So, the discriminative stimulus comes first and then, the behavior follows as a direct result of this stimulus.

A conditioned stimulus, on the other hand, produces the response, while the discriminative stimulus signals the opportunity to respond.

For example, if a bell tone were the conditioned stimulus, discrimination would involve being able to tell the difference between the bell sound and other similar sounds. Or, in advertising, the packaging on a certain brand of snack cookies might help buyers discriminate between multiple similar products.

7. Is generalization a conditioned response?

Yes, generalization can be a conditioned response. In classical conditioning, stimulus generalization is the tendency for the conditioned stimulus to evoke similar responses after the response has been conditioned.

Once a person or animal has been trained to respond to a stimulus, very similar stimuli may produce the same response as well.

The Little Albert experiment described above is an example of stimulus generalization. In this experiment, Little Albert was conditioned to fear a white rat. He thus continued to exhibit a fear of objects similar to the white rat, such as a dog, rabbit, fur coat, and a white Santa Claus beard.

Clark, R. E. (2004). The classical origins of Pavlov’s conditioning.  Integrative Physiological & Behavioral Science ,  39 (4), 279-294.

Gorn, G. J. (1982). The effects of music in advertising on choice behavior: A classical conditioning approach.  Journal of marketing ,  46 (1), 94-101.

Harris, B. (1979). Whatever happened to little Albert?.  American psychologist ,  34 (2), 151.

Hawkins, D., Best, R., & Coney, K. (1998.) Consumer Behavior: Building Marketing Strategy (7th ed.). Boston, MA: McGraw-Hill.

Pavlov, I. P. (1897/1902). The work of the digestive glands. London: Griffin.

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

Pavlov, I. P. (1927). Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex . Translated and edited by Anrep, GV (Oxford University Press, London, 1927).

Pavlov, I. P. (1955). Selected works . Moscow: Foreign Languages Publishing House.

Watson, J.B. (1913). Psychology as the behaviorist Views It. Psychological Review, 20 , 158-177.

Watson, J. B., & Rayner, R. (1920). Conditioned emotional reactions.  Journal of experimental psychology ,  3 (1), 1.

Classical Conditioning

Learning objectives.

• Explain how classical conditioning occurs
• Identify the NS, UCS, UCR, CS, and CR in classical conditioning situations

Does the name Ivan Pavlov ring a bell? Even if you are new to the study of psychology, chances are that you have heard of Pavlov and his famous dogs.

Pavlov (1849–1936), a Russian scientist, performed extensive research on dogs and is best known for his experiments in classical conditioning (Figure 1). As we discussed briefly in the previous section, classical conditioning is a process by which we learn to associate stimuli and, consequently, to anticipate events.

Figure 1 . Ivan Pavlov’s research on the digestive system of dogs unexpectedly led to his discovery of the learning process now known as classical conditioning.

Pavlov came to his conclusions about how learning occurs completely by accident. Pavlov was a physiologist, not a psychologist. Physiologists study the life processes of organisms, from the molecular level to the level of cells, organ systems, and entire organisms. Pavlov’s area of interest was the digestive system (Hunt, 2007). In his studies with dogs, Pavlov measured the amount of saliva produced in response to various foods. Over time, Pavlov (1927) observed that the dogs began to salivate not only at the taste of food, but also at the sight of food, at the sight of an empty food bowl, and even at the sound of the laboratory assistants’ footsteps. Salivating to food in the mouth is reflexive, so no learning is involved. However, dogs don’t naturally salivate at the sight of an empty bowl or the sound of footsteps.

These unusual responses intrigued Pavlov, and he wondered what accounted for what he called the dogs’ “psychic secretions” (Pavlov, 1927). To explore this phenomenon in an objective manner, Pavlov designed a series of carefully controlled experiments to see which stimuli would cause the dogs to salivate. He was able to train the dogs to salivate in response to stimuli that clearly had nothing to do with food, such as the sound of a bell, a light, and a touch on the leg. Through his experiments, Pavlov realized that an organism has two types of responses to its environment: (1) unconditioned (unlearned) responses, or reflexes, and (2) conditioned (learned) responses.

In Pavlov’s experiments, the dogs salivated each time meat powder was presented to them. The meat powder in this situation was an unconditioned stimulus (UCS) : a stimulus that elicits a reflexive response in an organism. The dogs’ salivation was an unconditioned response (UCR) : a natural (unlearned) reaction to a given stimulus. Before conditioning, think of the dogs’ stimulus and response like this:

In classical conditioning, a neutral stimulus is presented immediately before an unconditioned stimulus. Pavlov would sound a tone (like ringing a bell) and then give the dogs the meat powder (Figure 2). The tone was the neutral stimulus (NS), which is a stimulus that does not naturally elicit a response. Prior to conditioning, the dogs did not salivate when they just heard the tone because the tone had no association for the dogs. Quite simply this pairing means:

When Pavlov paired the tone with the meat powder over and over again, the previously neutral stimulus (the tone) also began to elicit salivation from the dogs. Thus, the neutral stimulus became the conditioned stimulus (CS) , which is a stimulus that elicits a response after repeatedly being paired with an unconditioned stimulus. Eventually, the dogs began to salivate to the tone alone, just as they previously had salivated at the sound of the assistants’ footsteps. The behavior caused by the conditioned stimulus is called the conditioned response (CR) . In the case of Pavlov’s dogs, they had learned to associate the tone (CS) with being fed, and they began to salivate (CR) in anticipation of food.

Figure 2 . Before conditioning, an unconditioned stimulus (food) produces an unconditioned response (salivation), and a neutral stimulus (bell) does not produce a response. During conditioning, the unconditioned stimulus (food) is presented repeatedly just after the presentation of the neutral stimulus (bell). After conditioning, the neutral stimulus alone produces a conditioned response (salivation), thus becoming a conditioned stimulus.

View the following video to learn more about Pavlov and his dogs:

You can view the transcript for “Classical Conditioning – Ivan Pavlov” here (opens in new window) .

Real World Application of Classical Conditioning

How does classical conditioning work in the real world? Consider the case of Moisha, who was diagnosed with cancer. When she received her first chemotherapy treatment, she vomited shortly after the chemicals were injected. In fact, every trip to the doctor for chemotherapy treatment shortly after the drugs were injected, she vomited. Moisha’s treatment was a success and her cancer went into remission. Now, when she visits her oncologist’s office every 6 months for a check-up, she becomes nauseous. In this case, the chemotherapy drugs are the unconditioned stimulus (UCS), vomiting is the unconditioned response (UCR), the doctor’s office is the conditioned stimulus (CS) after being paired with the UCS, and nausea is the conditioned response (CR). Let’s assume that the chemotherapy drugs that Moisha takes are given through a syringe injection. After entering the doctor’s office, Moisha sees a syringe, and then gets her medication. In addition to the doctor’s office, Moisha will learn to associate the syringe with the medication and will respond to syringes with nausea. This is an example of higher-order (or second-order) conditioning, when the conditioned stimulus (the doctor’s office) serves to condition another stimulus (the syringe). It is hard to achieve anything above second-order conditioning. For example, if someone rang a bell every time Moisha received a syringe injection of chemotherapy drugs in the doctor’s office, Moisha likely will never get sick in response to the bell.

Consider another example of classical conditioning. Let’s say you have a cat named Tiger, who is quite spoiled. You keep her food in a separate cabinet, and you also have a special electric can opener that you use only to open cans of cat food. For every meal, Tiger hears the distinctive sound of the electric can opener (“zzhzhz”) and then gets her food. Tiger quickly learns that when she hears “zzhzhz” she is about to get fed. What do you think Tiger does when she hears the electric can opener? She will likely get excited and run to where you are preparing her food. This is an example of classical conditioning. In this case, what are the UCS, CS, UCR, and CR?

What if the cabinet holding Tiger’s food becomes squeaky? In that case, Tiger hears “squeak” (the cabinet), “zzhzhz” (the electric can opener), and then she gets her food. Tiger will learn to get excited when she hears the “squeak” of the cabinet. Pairing a new neutral stimulus (“squeak”) with the conditioned stimulus (“zzhzhz”) is called higher-order conditioning, or second-order conditioning. This means you are using the conditioned stimulus of the can opener to condition another stimulus: the squeaky cabinet (Figure 3). It is hard to achieve anything above second-order conditioning. For example, if you ring a bell, open the cabinet (“squeak”), use the can opener (“zzhzhz”), and then feed Tiger, Tiger will likely never get excited when hearing the bell alone.

Figure 3 . In higher-order conditioning, an established conditioned stimulus is paired with a new neutral stimulus (the second-order stimulus), so that eventually the new stimulus also elicits the conditioned response, without the initial conditioned stimulus being presented.

Everyday Connection: Classical Conditioning at Stingray City

Figure 4 . Kate holds a southern stingray at Stingray City in the Cayman Islands. These stingrays have been classically conditioned to associate the sound of a boat motor with food provided by tourists. (credit: Kathryn Dumper)

Kate and her husband Scott recently vacationed in the Cayman Islands, and booked a boat tour to Stingray City, where they could feed and swim with the southern stingrays. The boat captain explained how the normally solitary stingrays have become accustomed to interacting with humans. About 40 years ago, fishermen began to clean fish and conch (unconditioned stimulus) at a particular sandbar near a barrier reef, and large numbers of stingrays would swim in to eat (unconditioned response) what the fishermen threw into the water; this continued for years. By the late 1980s, word of the large group of stingrays spread among scuba divers, who then started feeding them by hand. Over time, the southern stingrays in the area were classically conditioned much like Pavlov’s dogs. When they hear the sound of a boat engine (neutral stimulus that becomes a conditioned stimulus), they know that they will get to eat (conditioned response).

As soon as Kate and Scott reached Stingray City, over two dozen stingrays surrounded their tour boat. The couple slipped into the water with bags of squid, the stingrays’ favorite treat. The swarm of stingrays bumped and rubbed up against their legs like hungry cats (Figure 4). Kate and Scott were able to feed, pet, and even kiss (for luck) these amazing creatures. Then all the squid was gone, and so were the stingrays.

Classical conditioning also applies to humans, even babies. For example, Sara buys formula in blue canisters for her six-month-old daughter, Angelina. Whenever Sara takes out a formula container, Angelina gets excited, tries to reach toward the food, and most likely salivates. Why does Angelina get excited when she sees the formula canister? What are the UCS, CS, UCR, and CR here?

So far, all of the examples have involved food, but classical conditioning extends beyond the basic need to be fed. Consider our earlier example of a dog whose owners install an invisible electric dog fence. A small electrical shock (unconditioned stimulus) elicits discomfort (unconditioned response). When the unconditioned stimulus (shock) is paired with a neutral stimulus (the edge of a yard), the dog associates the discomfort (unconditioned response) with the edge of the yard (conditioned stimulus) and stays within the set boundaries.

For a humorous look at conditioning, you can watch an example from the television show  The Office . Jim conducts an experiment in which he offers Dwight a breath mint every time Jim’s computer makes a specific sound. After repeating this several times, he eventually conditions Dwight to automatically expect a breath mint upon hearing that sound.   See if you can identify the NS, UCS, UCR, CS, and CR.

Review the classical conditioning concepts yet again by walking through Pavlov’s research in the following interactive:

Think It Over

Can you think of an example in your life of how classical conditioning has produced a positive emotional response, such as happiness or excitement? How about a negative emotional response, such as fear, anxiety, or anger?

• Modification and adaptation, addition of tutorial. Provided by : Lumen Learning. License : CC BY: Attribution
• Classical conditioning interactive. Authored by : Jessica Traylor for Lumen Learning. Provided by : Lumen Learning. License : CC BY: Attribution
• Classical Conditioning. Authored by : OpenStax College. Located at : https://openstax.org/books/psychology-2e/pages/6-2-classical-conditioning . License : CC BY: Attribution . License Terms : Download for free at https://openstax.org/books/psychology-2e/pages/1-introduction
• Classical Conditioning - Ivan Pavlov. Authored by : BullyingNewsVideos. Located at : https://www.youtube.com/watch?v=hhqumfpxuzI . License : Other . License Terms : Standard YouTube License
• The Office Classical Conditioning. Authored by : Susann Stanley. Provided by : Vimeo. Located at : https://vimeo.com/35754924 . License : All Rights Reserved

• Mental Health

Classical Conditioning: How It Works and Examples

What Is Classical Conditioning?

Classical conditioning, also called Pavlovian conditioning or respondent conditioning, is learning through association. This behavioral learning method was first studied in the late 19th century by Russian physiologist Ivan Pavlov. 

Pavlov’s dog experiment

In the 1890s, Pavlov was experimenting with dogs, ringing a bell whenever they were fed. Over time, the dogs learned to associate a neutral stimulus (bell ringing) with a positive one (food). Pavlov also noticed that his dogs would often begin to salivate whenever they heard the footsteps of his assistant bringing them the food. This is called a conditioned response. Pavlov's experiment and its association between positive and neutral stimuli became the foundation of classical conditioning theory.

Eventually, Pavlov linked these behavioral associations to humans. He spent the remainder of his career studying the phenomenon.

Terms to Know

To understand how classical conditioning works, it's helpful to understand the following terms.

• Neutral stimulus. A stimulus is something that triggers a physical or behavioral change. A neutral stimulus produces no response. At first, Pavlov's dogs had no response to the bell.
• Unconditioned stimulus. This is what leads to an automatic response. In Pavlov’s experiment, it's the food.
• Unconditioned response . A normal process, like salivating when you smell food, is an unconditioned response.
• Conditioned stimulus. This is when a formerly neutral stimulus, like the bell in Pavlov's experiment, mimics an unconditioned response, as when the dogs began to associate the bell with food and salivate.
• Conditioned response. The learned behavior, such as relating the bell to food, is called a conditioned response.  

What Is Classical Conditioning Theory?

Classical conditioning theory says that behaviors are learned by connecting a neutral stimulus with a positive one, such as when Pavlov's dogs heard a bell (neutral) and expected food (positive).  

There are essentially three stages in classical conditioning:.

Before conditioning. Something in the environment triggers a natural response in the subject. During this stage, no new behavior has been learned yet. This stage also includes a neutral stimulus, which doesn't affect the subject. To create a response to a neutral stimulus, it must be linked to an unconditioned stimulus -- like the bell to food. 

During conditioning. This is the stage in which the subject starts to associate the neutral stimulus with the positive stimulus that caused the response during the first stage. In Pavlov's experiment, this stage involved ringing a bell when the dogs were fed. Over time, the dogs began to associate the bell with food.

For this to work, the neutral stimulus should come before the positive (unconditioned) stimulus. It creates a cue for what comes next. Doing this over and over makes the conditioning stick. But sometimes it only takes one time to make an association, such as a hangover after too much drinking. 

After conditioning. During the final stage of conditioning, the subject firmly associates the neutral stimulus with the unconditioned response. This creates a new behavior, or what's known as the conditioned response. If the link between the two weakens or breaks, this leads to what's called extinction. When Pavlov's dogs no longer got food after hearing the bell, they eventually stopped associating the bell with food.

What Is the Little Albert Experiment?

Considered one of the "most ethically dubious experiments ever conducted," the Little Albert experiment was developed by psychologists John B. Watson and Rosalie Rayner, who first applied Pavlov's classical conditioning principles to human behavior.

In 1920, Watson and Rayner began their behavioral learning experiment with a 9-month-old boy named Albert. They tested his reactions to various things in his environment, including a white rat, burning newspapers, and a hammer striking a 4-foot steel bar just behind Albert's head. Because the sound of the hammer frightened Albert, it became the unconditioned stimulus, and fear became the unconditioned response.

When Albert was 11 months old, he was presented with the white rat. When he tried to pet it, the pipe was struck with the hammer, causing him to feel fear. The researchers did this over the next few weeks and eventually Albert saw the rat and showed a fearful response. 

They reproduced these results with a rabbit, a dog, and several other stimuli that were previously neutral. At the end of the experiment, Albert showed a fear response for all of them.

Classical Conditioning vs. Operant Conditioning

Classical conditioning relies on associating one stimulus with another, such as the sound of a bell with food. Learning through operant conditioning relies on what comes after behaviors. These are the consequences that reinforce or punish behaviors.

In operant conditioning, either positive or negative reinforcement is used to affect whether a behavior is likely to happen again.  

When you give your dog a treat after they follow a command, that's positive reinforcement. It encourages them to repeat the behavior. When you yell (punishment) after your dog grabs food off the counter, that's punishment or negative reinforcement. Like classical conditioning, operant conditioning requires repetition for learning to take place. 

Classical Conditioning Principles

Classical conditioning includes several steps:

Acquisition. The point at which the neutral stimulus and unconditioned stimulus become linked. In other words, the dog learns to relate the sound of the bell with food.  

Extinction. Extinction breaks the conditioned bonds between the stimuli. If the dog no longer sees food after hearing the bell, it will gradually stop associating the bell with food.

Spontaneous recovery. If, after extinction, the conditioned stimulus and neutral stimulus again appear in relationship to one another, the conditioned response will return. After the extinction of the conditioned response in his dogs, Pavlov rang the bell before producing the food a few days later. His dogs began to salivate at the sound of the bell again.

Generalization. A conditioned response may be produced with stimuli that are similar but not the same. For example, if Pavlov's dogs heard a bell that rang at a lower pitch and still salivated, that's generalization.

Discrimination. Discrimination is the ability to understand that two or more stimuli are different from one another. In Pavlov's experiment, he later introduced the dogs to two bell sounds. Food appeared only after one. The dogs soon learned the difference. 

Classical Conditioning Examples

Classical conditioning isn't just related to food or fear. You see examples of this type of conditioning every day, though you may not know it or consciously think about it. Here are some examples of classical conditioning in daily life.

• Every time you put on your shoes, your dog gets excited and runs to the front door. Your dog associates you putting on shoes with a walk, or maybe going for a car ride.
• You always buy the same type of crackers for your baby's morning snack. When you pull the box of crackers out of the cupboard, your baby gets excited and reaches toward the box because they associate that box with snack time.
• A certain perfume reminds you of your late grandmother. After her passing, smelling that perfume or similar scents make you sad because of its association with your grandmother.
• Your demanding boss occasionally berates underperforming employees in his office. You feel nervous or agitated whenever your boss asks one of your co-workers into his office and closes the door because that's what he does whenever someone's in trouble.
• You listen to your favorite music when you exercise. You don't generally enjoy working out, but eventually, you begin to relate the positive feelings you get from your playlist to working out.
• Advertising. You see an ad showing a cold, wet can of soda while pumping your gas. You start feeling thirsty and think about running inside and buying this soft drink. 

Classical Conditioning Uses

Psychologists consider classical conditioning a key type of learning. It can create changes in mental and physical health, emotions, and drive. Its uses include: 

• Phobias. Repeated exposure to the object of a phobia, such as frequently flying when you're afraid of planes, can reduce fears.
• Drug use. Counselors often urge former addicts to stay away from people and places associated with their drug use.
• Classroom learning. Teachers might use classical conditioning to associate learning with positive emotions rather than negative ones like fear or shame.
• Pet training. Classical conditioning taught Pavlov's dogs what to expect after they heard the bell: food. Your dog also learns to positively associate actions like picking up a leash with going for a walk or going out to pee.
• Food aversions. We're born favoring certain tastes more than others (like sweet vs. bitter). If you eat something and become sick, you might learn to avoid the food and even feel sick at the sight of it. 
• PTSD  For people with posttraumatic stress disorder (PTSD) , classical conditioning may not cure their condition but contribute to it. PTSD is a type of anxiety that comes from associating certain triggers with fearful experiences. For example, loud noises may remind a veteran of the sounds of war. 

Criticisms of Classical Conditioning

Classical conditioning stresses outward learning over traits we're born with. Some criticisms of classical conditioning include:

• It fails to consider complex human actions like thinking, reason, and memory that produce learning, too. 
• It takes a long time to make the associations that create learning.
• It assumes a lack of free will -- that people have no control over their reactions to stimuli.

Classical conditioning is a type of learning by association. It takes several steps to associate a neutral stimulus with a positive outcome. Classical conditioning is used to treat psychological problems such as drug addiction and phobias. But it's also the basis for posttraumatic stress disorder (PTSD). Classical conditioning appears in everyday life in advertising and in our sensory associations with good and bad events. 

Classical Conditioning FAQs

• What is the simple definition of classical conditioning? Classical conditioning is learning through association.  
• What is an example of classical conditioning? Listening to your favorite music during workouts is an example of associating exercise with a positive neutral stimulus.  
• What are the five elements of classical conditioning?  Elements of classical conditioning include acquisition, extinction, spontaneous recovery, generalization, and discrimination.

Top doctors in ,

Find more top doctors on, related links.

• Mental Health Home
• Mental Health News & Features
• Mental Health Reference
• Mental Health Quizzes
• Mental Health Slideshows
• Mental Health Blogs
• Mental Health Videos
• Find a Psychiatrist
• Anxiety & Panic Disorders
• Bipolar Disorder
• Crisis Assistance
• Eating Disorders
• Health & Balance
• Personality Disorders
• Schizophrenia
• Social Media and Mental Health
• Stress Management
• Substance Abuse & Addiction
• More Related Topics

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

Chapter 8. Learning

Classical Conditioning

Dinesh Ramoo

Approximate reading time: 28 minutes

Learning Objectives

By the end of this section, you will be able to:

• Explain how classical conditioning occurs
• Summarise the processes of acquisition, extinction, spontaneous recovery, generalisation, and discrimination

Ivan Pavlov

Does the name Ivan Pavlov ring a bell? Even if you are new to the study of psychology, chances are that you have heard of Pavlov and his famous dogs.

Pavlov (1849–1936), a Russian scientist, performed extensive research on dogs and is best known for his experiments in classical conditioning (Figure L.3). As we discussed briefly in the previous section, classical conditioning is a process by which we learn to associate stimuli with results and, consequently, to anticipate events.

Pavlov came to his conclusions about how learning occurs completely by accident. Pavlov was a physiologist, not a psychologist. Physiologists study the life processes of organisms, from the molecular level to the level of cells, organ systems, and entire organisms. Pavlov’s area of interest was the digestive system (Hunt, 2007). He was the first Russian to win the Nobel Prize for his contributions to medicine. In his studies with dogs, Pavlov measured the amount of saliva produced in response to various foods. Over time, Pavlov (1927) observed that the dogs began to salivate not only at the taste of food, but also at the sight of food, at the sight of an empty food bowl, and even at the sound of the laboratory assistants’ footsteps. Salivating to food in the mouth is reflexive, so no learning is involved. However, dogs don’t naturally salivate at the sight of an empty bowl or the sound of footsteps.

These unusual responses intrigued Pavlov, and he wondered what accounted for what he called the dogs’ “psychic secretions” (Pavlov, 1927). To explore this phenomenon objectively, Pavlov designed a series of carefully controlled experiments to see which stimuli would cause the dogs to salivate. He was able to train the dogs to salivate in response to stimuli that clearly had nothing to do with food, such as the sound of a bell, a light, and a touch on the leg. Through his experiments, Pavlov realised that an organism has two types of responses to its environment: (1) unconditioned (unlearned) responses, or reflexes, and (2) conditioned (learned) responses.

In Pavlov’s experiments, the dogs salivated each time meat powder was presented to them. The meat powder in this situation was an unconditioned stimulus (US): a stimulus that elicits a reflexive response in an organism. The dogs’ salivation was an unconditioned response (UCR): a natural (unlearned) reaction to a given stimulus. Before conditioning, think of the dogs’ stimulus and response like this:

Meat powder (US) → Salivation (UCR)

In classical conditioning, a neutral stimulus is presented immediately before an unconditioned stimulus. Pavlov would sound a tone (like a bell ringing) and then give the dogs the meat powder (Figure L.4). The tone was the neutral stimulus (NS), which is a stimulus that does not naturally elicit a response. Prior to conditioning, the dogs did not salivate when they just heard the tone because the tone had no association for the dogs.

Tone (NS) + Meat Powder (US) → Salivation (UCR)

When Pavlov paired the tone with the meat powder over and over again, the previously neutral stimulus (the tone) also began to elicit salivation from the dogs. Thus, the neutral stimulus became the conditioned stimulus (CS), which is a stimulus that elicits a response after repeatedly being paired with an unconditioned stimulus. Eventually, the dogs began to salivate to the tone alone, just as they previously had salivated at the sound of the assistants’ footsteps. The behaviour caused by the conditioned stimulus is called the conditioned response (CR). In the case of Pavlov’s dogs, they had learned to associate the tone (CS) with being fed, and they began to salivate (CR) in anticipation of food.

View this video about Pavlov and his dogs to learn more: Pavlov’s Classical Conditioning (6 minutes)

“Pavlov’s Classical Conditioning” video by Sprouts is licensed under the Standard YouTube licence.

Real World Application of Classical Conditioning

How does classical conditioning work in the real world?

Let’s say you have a cat named Zelda, who is quite spoiled. You keep Zelda’s food in a separate cabinet, and you also have a special electric can opener that you use only to open cans of cat food. For every meal, Zelda hears the distinctive sound of the electric can opener (“zzhzhz”) and then gets her food. Zelda quickly learns that when she hears “zzhzhz” that means it’s feeding time. What do you think Zelda does when she hears the electric can opener? Zelda will likely get excited and run to where you are preparing their food. This is an example of classical conditioning. In this case, what are the US, CS, UCR, and CR?

What if the cabinet holding Zelda’s food becomes squeaky? In that case, Zelda hears “squeak” (the cabinet), “zzhzhz” (the electric can opener), and then she gets the food. Zelda will learn to get excited when she hears the “squeak” of the cabinet. Pairing a new neutral stimulus (“squeak”) with the conditioned stimulus (“zzhzhz”) is called higher-order conditioning , or second-order conditioning . This means you are using the conditioned stimulus of the can opener to condition another stimulus: the squeaky cabinet (Figure L.5). It is hard to achieve anything above second-order conditioning. For example, if you ring a bell, open the cabinet (“squeak”), use the can opener (“zzhzhz”), and then feed Zelda, Zelda will likely never get excited when hearing the bell alone.

Now consider the case of Farah, who was diagnosed with cancer. When Farah received their first chemotherapy treatment, they vomited shortly after the chemicals were injected. In fact, on every trip to the doctor for chemotherapy treatment, shortly after the drugs were injected, Farah vomited. Farah’s treatment was a success and their cancer went into remission. Now, when Farah visits their oncologist’s office every 6 months for a check-up, they become nauseous. In this case, the chemotherapy drugs are the unconditioned stimulus (US), vomiting is the unconditioned response (UCR), the doctor’s office is the conditioned stimulus (CS) after being paired with the US, and nausea is the conditioned response (CR). Let’s assume that the chemotherapy drugs that Farah takes are given through a syringe injection. After entering the doctor’s office, Farah sees a syringe, and then gets their medication. In addition to the doctor’s office, Farah will learn to associate the syringe with the medication and will respond to syringes with nausea. This is an example of higher-order (or second-order) conditioning, when the conditioned stimulus (the doctor’s office) serves to condition another stimulus (the syringe). Because it is hard to achieve anything above second-order conditioning, if someone rang a bell, for example, every time Farah received a syringe injection of chemotherapy drugs in the doctor’s office, Farah likely would not get sick in response to the bell.

Classical conditioning  even applies to babies. For example, Logan buys formula in blue canisters for their six-month-old baby, Reagan. Whenever Logan takes out a formula container, Reagan gets excited, tries to reach toward the food, and most likely salivates. Why does Reagan get excited when they see the formula canister? What are the US, CS, UCR, and CR here?

So far, all of the examples have involved food, but classical conditioning extends beyond the basic need to be fed. Consider our earlier example of a dog whose owners install an invisible electric dog fence. A small electrical shock (unconditioned stimulus) elicits discomfort (unconditioned response). When the unconditioned stimulus (shock) is paired with a neutral stimulus (the edge of a yard), the dog associates the discomfort (unconditioned response) with the edge of the yard (conditioned stimulus) and stays within the set boundaries. In this example, the edge of the yard elicits fear and anxiety in the dog. Fear and anxiety are the conditioned response.

Everyday Connection: Classical Conditioning at Stingray City

Kate and her spouse recently vacationed in the Cayman Islands, and booked a boat tour to Stingray City, where they could feed and swim with the southern stingrays. The boat captain explained how the normally solitary stingrays have become accustomed to interacting with humans. About 40 years ago, fishermen began to clean fish and conch (unconditioned stimulus) at a particular sandbar near a barrier reef, and large numbers of stingrays would swim in to eat (unconditioned response) what the fishermen threw into the water; this continued for years. By the late 1980s, word of the large group of stingrays spread among scuba divers, who then started feeding them by hand. Over time, the southern stingrays in the area were classically conditioned much like Pavlov’s dogs. When they hear the sound of a boat engine (neutral stimulus that becomes a conditioned stimulus), they know that they will get to eat (conditioned response).

As soon as they reached Stingray City, over two dozen stingrays surrounded their tour boat. The couple slipped into the water with bags of squid, the stingrays’ favourite treat.

The swarm of stingrays bumped and rubbed up against their legs like hungry cats (Figure L.6). Kate was able to feed, pet, and even kiss (for luck) these amazing creatures. Then all the squid was gone, and so were the stingrays.

General Processes in Classical Conditioning

Acquisition.

Now that you know how classical conditioning works and have seen several examples, let’s take a look at some of the general processes involved. In classical conditioning, the initial period of learning is known as acquisition , when an organism learns to connect a neutral stimulus and an unconditioned stimulus. During acquisition, the neutral stimulus begins to elicit the conditioned response, and eventually the neutral stimulus becomes a conditioned stimulus capable of eliciting the conditioned response by itself. Timing is important for conditioning to occur. Typically, there should be only a brief interval between presentation of the conditioned stimulus and the unconditioned stimulus. Depending on what is being conditioned, sometimes this interval is as little as five seconds (Chance, 2009). However, with other types of conditioning, the interval can be up to several hours.

Taste aversion is a type of conditioning in which an interval of several hours may pass between the conditioned stimulus (something ingested) and the unconditioned stimulus (nausea or illness). Here’s how it works. Between classes, you and a friend grab a quick lunch from a food cart on campus. You share a dish of chicken curry and head off to your next class. A few hours later, you feel nauseous and become ill. Although your friend is fine and you determine that you have intestinal flu (the food is not the culprit), you’ve developed a taste aversion; the next time you are at a restaurant and someone orders curry, you immediately feel ill. While the chicken dish is not what made you sick, you are experiencing taste aversion: you’ve been conditioned to be averse to a food after a single, bad experience.

How does conditioning occur based on a single instance and involving an extended time lapse between the event and the negative stimulus? Research into taste aversion suggests that this response may be an evolutionary adaptation designed to help organisms quickly learn to avoid harmful foods (Garcia & Rusiniak, 1980; Garcia & Koelling, 1966). Not only may this contribute to species survival via natural selection, but it may also help us develop strategies for challenges, such as helping cancer patients through the nausea induced by certain treatments (Holmes, 1993; Jacobsen et al., 1993; Hutton, Baracos, & Wismer, 2007; Skolin et al., 2006). But why would a person develop an aversion to the taste or smell of a food rather than to all the other stimuli that accompanied the food? Why not the cutlery or the music that was playing at the time?

Garcia and Koelling (1966) showed not only that taste aversions could be conditioned, but also that there were biological constraints to learning. In their study, separate groups of rats were conditioned to associate either a flavour with illness, or lights and sounds with illness. Results showed that all rats exposed to flavour-illness pairings learned to avoid the flavour, but none of the rats exposed to lights and sounds with illness learned to avoid lights or sounds. This added evidence to the idea that classical conditioning could contribute to species survival by helping organisms learn to avoid stimuli that posed real dangers to health and welfare.

Robert Rescorla demonstrated how powerfully an organism can learn to predict the US from the CS. Take, for example, the following two situations. Tafadawa’s family always has dinner on the table every day at 6:00. Hai’s family switches it up so that some days they eat dinner at 6:00, some days they eat at 5:00, and other days they eat at 7:00. For Tafadawa, 6:00 reliably and consistently predicts dinner, so Tafadawa will likely start feeling hungry every day right before 6:00, even if he’s had a late snack. Hai, on the other hand, will be less likely to associate 6:00 with dinner, since 6:00 does not always predict that dinner is coming. Rescorla, along with his colleague at Yale University, Alan Wagner, developed a mathematical formula that could be used to calculate the probability that an association would be learned given the ability of a conditioned stimulus to predict the occurrence of an unconditioned stimulus and other factors; today this is known as the Rescorla-Wagner model (Rescorla & Wagner, 1972). We also know that conditioning can be unrelated to food. It can also trigger an emotional response, rather than a physical one. For example, if an experimenter sounds a tone just before applying a mild shock to a rat’s feet, the tone will elicit fear or anxiety after one or two pairings. Similar fear conditioning plays a role in creating many anxiety disorders in humans, such as phobias and panic disorders, where people associate cues (such as closed spaces, or a shopping mall) with panic or other emotional trauma. Here, rather than a physical response (like drooling), the CS triggers an emotion.

Once we have established the connection between the unconditioned stimulus and the conditioned stimulus, how do we break that connection and get the dog, cat, or child to stop responding? In Zelda’s case, imagine what would happen if you stopped using the electric can opener for her food and began to use it only for human food. Now, Zelda would hear the can opener, but she would not get food. In classical conditioning terms, you would be giving the conditioned stimulus, but not the unconditioned stimulus. Pavlov explored this scenario in his experiments with dogs: sounding the tone without giving the dogs the meat powder. Soon the dogs stopped responding to the tone. Extinction is the decrease in the conditioned response when the unconditioned stimulus is no longer presented with the conditioned stimulus. When presented with the conditioned stimulus alone, the dog, cat, or other organism would show a weaker and weaker response, and finally no response. In classical conditioning terms, there is a gradual weakening and disappearance of the conditioned response.

What happens when learning is not used for a while—when what was learned lies dormant? As we just discussed, Pavlov found that when he repeatedly presented the bell (conditioned stimulus) without the meat powder (unconditioned stimulus), extinction occurred; the dogs stopped salivating to the bell. However, after a couple of hours of resting from this extinction training, the dogs again began to salivate when Pavlov rang the bell. What do you think would happen with Zelda’s behaviour if your electric can opener broke, and you did not use it for several months? When you finally got it fixed and started using it to open Zelda’s food again, Zelda would remember the association between the can opener and food—she  would get excited and run to the kitchen when she heard the sound. The behaviour of Pavlov’s dogs and Zelda illustrates a concept Pavlov called spontaneous recovery : the return of a previously extinguished conditioned response following a rest period (Figure L.7).

Of course, these processes also apply in humans. For example, let’s say that every day when you walk to campus, an ice cream truck passes your route. Day after day, you hear the truck’s music (neutral stimulus), so you finally stop and purchase a chocolate ice cream bar. You take a bite (unconditioned stimulus) and then your mouth waters (unconditioned response). This initial period of learning is known as acquisition, when you begin to connect the neutral stimulus (the sound of the truck) and the unconditioned stimulus (the taste of the chocolate ice cream in your mouth). During acquisition, the conditioned response gets stronger and stronger through repeated pairings of the conditioned stimulus and unconditioned stimulus. Several days (and ice cream bars) later, you notice that your mouth begins to water (conditioned response) as soon as you hear the truck’s musical jingle—even before you bite into the ice cream bar. Then one day you head down the street. You hear the truck’s music (conditioned stimulus), and your mouth waters (conditioned response). However, when you get to the truck, you discover that they are all out of ice cream. You leave disappointed. The next few days you pass by the truck and hear the music, but don’t stop to get an ice cream bar because you’re running late for class. You begin to salivate less and less when you hear the music, until by the end of the week, your mouth no longer waters when you hear the tune. This illustrates extinction. The conditioned response weakens when only the conditioned stimulus (the sound of the truck) is presented, without being followed by the unconditioned stimulus (chocolate ice cream in the mouth). Then the weekend comes. You don’t have to go to class, so you don’t pass the truck. Monday morning arrives and you take your usual route to campus. You round the corner and hear the truck again. What do you think happens? Your mouth begins to water again. Why? After a break from conditioning, the conditioned response reappears, which indicates spontaneous recovery.

Acquisition and extinction involve the strengthening and weakening, respectively, of a learned association. Two other learning processes— stimulus discrimination and stimulus generalisation—are involved in determining which stimuli will trigger learned responses. Animals (including humans) need to distinguish between stimuli—for example, between sounds that predict a threatening event and sounds that do not—so that they can respond appropriately (such as running away if the sound is threatening). When an organism learns to respond differently to various stimuli that are similar, it is called stimulus discrimination. In classical conditioning terms, the organism demonstrates the conditioned response only to the conditioned stimulus. Pavlov’s dogs discriminated between the basic tone that sounded before they were fed and other tones (e.g., the doorbell) because the other sounds did not predict the arrival of food. Similarly, Zelda, the cat, discriminated between the sound of the can opener and the sound of the electric mixer. When the electric mixer is going, Zelda is not about to be fed, so she does  not come running to the kitchen looking for food. In our other example, Farah, the cancer patient, discriminated between oncologists and other types of doctors. Farah learned not to feel ill when visiting doctors for other types of appointments, such as their annual physical.

On the other hand, when an organism demonstrates the conditioned response to stimuli that are similar to the condition stimulus, it is called stimulus generalisation , the opposite of stimulus discrimination. The more similar a stimulus is to the condition stimulus, the more likely the organism is to give the conditioned response. For instance, if the electric mixer sounds very similar to the electric can opener, Zelda may come running after hearing its sound. But if you do not feed Zelda following the electric mixer sound, and you continue to feed her consistently after the electric can opener sound, Zelda will quickly learn to discriminate between the two sounds (provided they are sufficiently dissimilar that she can tell them apart). In our other example, Farah continued to feel ill whenever visiting other oncologists or other doctors in the same building as their oncologist.

Behaviourism

John B. Watson, shown in Figure L.8, is considered the founder of behaviourism. Behaviourism is a school of thought that arose during the first part of the 20th century, incorporating elements of Pavlov’s classical conditioning (Hunt, 2007). In many ways, behaviourism arose as a response to what many saw as the unscientific, even mystical direction that psychology was taking in the early 20th century. Psychoanalysis postulated quite a few unfalsifiable and unquantifiable entities such as the unconscious, impulses, the ego, and the id, among others. Psychologists were being presented with conclusions from case studies done by Freud and his colleagues as evidence but there was no way to replicate those findings. In stark contrast with Freud, who considered the reasons for behaviour to be hidden in the unconscious, Watson championed the idea that all behaviour can be studied as a simple stimulus-response reaction, without regard for internal processes. Such processes were observable and measurable. The experiments could be replicated by other psychologists to test whether the postulates were universal. Watson argued that, in order for psychology to become a legitimate science, it must shift its concern away from internal mental processes because mental processes cannot be seen or measured. Instead, he asserted that psychology must focus on outward observable behaviour that can be measured.

Watson’s ideas were influenced by Pavlov’s work. According to Watson, human behaviour, just like animal behaviour, is primarily the result of conditioned responses. Whereas Pavlov’s work with dogs involved the conditioning of reflexes, Watson believed the same principles could be extended to the conditioning of human emotions (Watson, 1919). Thus began Watson’s work with his graduate student Rosalie Rayner and a baby called Little Albert. Through their experiments with Little Albert, Watson and Rayner (1920) demonstrated how fears can be conditioned.

In 1920, Watson was the chair of the psychology department at Johns Hopkins University. Through his position at the university he came to meet Little Albert’s mother, Arvilla Merritte, who worked at a campus hospital (DeAngelis, 2010). Watson offered her a dollar to allow her son to be the subject of his experiments in classical conditioning. Through these experiments, Little Albert was exposed to and conditioned to fear certain things. Initially he was presented with various neutral stimuli, including a rabbit, a dog, a monkey, masks, cotton wool, and a white rat. He was not afraid of any of these things. Then Watson, with the help of Rayner, conditioned Little Albert to associate these stimuli with an emotion—fear. For example, Watson handed Little Albert the white rat, and Little Albert enjoyed playing with it. Then Watson made a loud sound, by striking a hammer against a metal bar hanging behind Little Albert’s head, each time Little Albert touched the rat. Little Albert was frightened by the sound—demonstrating a reflexive fear of sudden loud noises—and began to cry. Watson repeatedly paired the loud sound with the white rat. Soon Little Albert became frightened by the white rat alone. In this case, what are the US, CS, UCR, and CR? Days later, Little Albert demonstrated stimulus generalisation—he became afraid of other furry things: a rabbit, a furry coat, and even a Santa Claus mask (Figure LE.9). Watson had succeeded in conditioning a fear response in Little Albert, thus demonstrating that emotions could become conditioned responses. It had been Watson’s intention to produce a phobia—a persistent, excessive fear of a specific object or situation— through conditioning alone, thus countering Freud’s view that phobias are caused by deep, hidden conflicts in the mind. However, there is no evidence that Little Albert experienced phobias in later years. Little Albert’s mother moved away, ending the experiment. While Watson’s research provided new insight into conditioning, it would be considered unethical by today’s standards.

View scenes from this video on John Watson’s experiment in which “Little Albert” was conditioned to respond in fear to furry objects, to learn more.

Watch this video: Baby Albert Experiments (3.5 minutes)

“ Baby Albert Experiments ” video by Jaap van der Steen is licensed under the Standard YouTube licence. The footage is in the public domain.

Image Attributions

Figure LE.3. “ Ivan Pavlov NLM3″  is in the public domain .

Figure LE.4. Figure 6.4 as found in Psychology 2e by OpenStax is licensed under a CC BY 4.0 License .

Figure LE.5. Figure 6.5 as found in Psychology 2e by OpenStax is licensed under a CC BY 4.0 License .

Figure LE.6. Figure 6.6 as found in Psychology 2e by OpenStax is licensed under a CC BY 4.0 License .

Figure LE.7. Figure 6.7 as found in Psychology 2e by OpenStax is licensed under a CC BY 4.0 License .

Figure LE.8. “John B. Watson” from the Johns Hopkins Gazette is in the public domain .

Figure LE.9. “ Little Albert ” from the Akron Psychology Archives is in the public domain .

To calculate this time, we used a reading speed of 150 words per minute and then added extra time to account for images and videos. This is just to give you a rough idea of the length of the chapter section. How long it will take you to engage with this chapter will vary greatly depending on all sorts of things (the complexity of the content, your ability to focus, etc).

learning in which the stimulus or experience occurs before the behaviour and then gets paired or associated with the behaviour

using a conditioned stimulus to condition a neutral stimulus

period of initial learning in classical conditioning in which a human or an animal begins to connect a neutral stimulus and an unconditioned stimulus so that the neutral stimulus will begin to elicit the conditioned response

a type of classical conditioning that elicits a fear response

decrease in the conditioned response when the unconditioned stimulus is no longer paired with the conditioned stimulus

return of a previously extinguished conditioned response

ability to respond differently to similar stimuli

demonstrating the conditioned response to stimuli that are similar to the conditioned stimulus

Classical Conditioning Copyright © 2024 by Dinesh Ramoo is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

Share This Book

6.2 Classical Conditioning

Learning objectives.

By the end of this section, you will be able to:

• Explain how classical conditioning occurs
• Summarize the processes of acquisition, extinction, spontaneous recovery, generalization, and discrimination

Does the name Ivan Pavlov ring a bell? Even if you are new to the study of psychology, chances are that you have heard of Pavlov and his famous dogs.

Pavlov (1849–1936), a Russian scientist, performed extensive research on dogs and is best known for his experiments in classical conditioning ( Figure 6.3 ). As we discussed briefly in the previous section, classical conditioning is a process by which we learn to associate stimuli and, consequently, to anticipate events.

Pavlov came to his conclusions about how learning occurs completely by accident. Pavlov was a physiologist, not a psychologist. Physiologists study the life processes of organisms, from the molecular level to the level of cells, organ systems, and entire organisms. Pavlov’s area of interest was the digestive system (Hunt, 2007). In his studies with dogs, Pavlov measured the amount of saliva produced in response to various foods. Over time, Pavlov (1927) observed that the dogs began to salivate not only at the taste of food, but also at the sight of food, at the sight of an empty food bowl, and even at the sound of the laboratory assistants' footsteps. Salivating to food in the mouth is reflexive, so no learning is involved. However, dogs don’t naturally salivate at the sight of an empty bowl or the sound of footsteps.

These unusual responses intrigued Pavlov, and he wondered what accounted for what he called the dogs' “psychic secretions” (Pavlov, 1927). To explore this phenomenon in an objective manner, Pavlov designed a series of carefully controlled experiments to see which stimuli would cause the dogs to salivate. He was able to train the dogs to salivate in response to stimuli that clearly had nothing to do with food, such as the sound of a bell, a light, and a touch on the leg. Through his experiments, Pavlov realized that an organism has two types of responses to its environment: (1) unconditioned (unlearned) responses, or reflexes, and (2) conditioned (learned) responses.

In Pavlov’s experiments, the dogs salivated each time meat powder was presented to them. The meat powder in this situation was an unconditioned stimulus (UCS) : a stimulus that elicits a reflexive response in an organism. The dogs’ salivation was an unconditioned response (UCR) : a natural (unlearned) reaction to a given stimulus. Before conditioning, think of the dogs’ stimulus and response like this:

In classical conditioning, a neutral stimulus is presented immediately before an unconditioned stimulus. Pavlov would sound a tone (like ringing a bell) and then give the dogs the meat powder ( Figure 6.4 ). The tone was the neutral stimulus (NS) , which is a stimulus that does not naturally elicit a response. Prior to conditioning, the dogs did not salivate when they just heard the tone because the tone had no association for the dogs.

When Pavlov paired the tone with the meat powder over and over again, the previously neutral stimulus (the tone) also began to elicit salivation from the dogs. Thus, the neutral stimulus became the conditioned stimulus (CS) , which is a stimulus that elicits a response after repeatedly being paired with an unconditioned stimulus. Eventually, the dogs began to salivate to the tone alone, just as they previously had salivated at the sound of the assistants’ footsteps. The behavior caused by the conditioned stimulus is called the conditioned response (CR) . In the case of Pavlov’s dogs, they had learned to associate the tone (CS) with being fed, and they began to salivate (CR) in anticipation of food.

Link to Learning

View this video about Pavlov and his dogs to learn more.

Real World Application of Classical Conditioning

How does classical conditioning work in the real world? Consider the case of Moisha, who was diagnosed with cancer. When she received her first chemotherapy treatment, she vomited shortly after the chemicals were injected. In fact, every trip to the doctor for chemotherapy treatment shortly after the drugs were injected, she vomited. Moisha’s treatment was a success and her cancer went into remission. Now, when she visits her oncologist's office every 6 months for a check-up, she becomes nauseous. In this case, the chemotherapy drugs are the unconditioned stimulus (UCS), vomiting is the unconditioned response (UCR), the doctor’s office is the conditioned stimulus (CS) after being paired with the UCS, and nausea is the conditioned response (CR). Let's assume that the chemotherapy drugs that Moisha takes are given through a syringe injection. After entering the doctor's office, Moisha sees a syringe, and then gets her medication. In addition to the doctor's office, Moisha will learn to associate the syringe with the medication and will respond to syringes with nausea. This is an example of higher-order (or second-order) conditioning, when the conditioned stimulus (the doctor's office) serves to condition another stimulus (the syringe). It is hard to achieve anything above second-order conditioning. For example, if someone rang a bell every time Moisha received a syringe injection of chemotherapy drugs in the doctor's office, Moisha likely will never get sick in response to the bell.

Consider another example of classical conditioning. Let’s say you have a cat named Tiger, who is quite spoiled. You keep her food in a separate cabinet, and you also have a special electric can opener that you use only to open cans of cat food. For every meal, Tiger hears the distinctive sound of the electric can opener (“zzhzhz”) and then gets her food. Tiger quickly learns that when she hears “zzhzhz” she is about to get fed. What do you think Tiger does when she hears the electric can opener? She will likely get excited and run to where you are preparing her food. This is an example of classical conditioning. In this case, what are the UCS, CS, UCR, and CR?

What if the cabinet holding Tiger’s food becomes squeaky? In that case, Tiger hears “squeak” (the cabinet), “zzhzhz” (the electric can opener), and then she gets her food. Tiger will learn to get excited when she hears the “squeak” of the cabinet. Pairing a new neutral stimulus (“squeak”) with the conditioned stimulus (“zzhzhz”) is called higher-order conditioning , or second-order conditioning . This means you are using the conditioned stimulus of the can opener to condition another stimulus: the squeaky cabinet ( Figure 6.5 ). It is hard to achieve anything above second-order conditioning. For example, if you ring a bell, open the cabinet (“squeak”), use the can opener (“zzhzhz”), and then feed Tiger, Tiger will likely never get excited when hearing the bell alone.

Everyday Connection

Classical conditioning at stingray city.

Kate and her spouse recently vacationed in the Cayman Islands, and booked a boat tour to Stingray City, where they could feed and swim with the southern stingrays. The boat captain explained how the normally solitary stingrays have become accustomed to interacting with humans. About 40 years ago, people began to clean fish and conch (unconditioned stimulus) at a particular sandbar near a barrier reef, and large numbers of stingrays would swim in to eat (unconditioned response) what the people threw into the water; this continued for years. By the late 1980s, word of the large group of stingrays spread among scuba divers, who then started feeding them by hand. Over time, the southern stingrays in the area were classically conditioned much like Pavlov’s dogs. When they hear the sound of a boat engine (neutral stimulus that becomes a conditioned stimulus), they know that they will get to eat (conditioned response).

As soon as they reached Stingray City, over two dozen stingrays surrounded their tour boat. The couple slipped into the water with bags of squid, the stingrays’ favorite treat. The swarm of stingrays bumped and rubbed up against their legs like hungry cats ( Figure 6.6 ). Kate was able to feed, pet, and even kiss (for luck) these amazing creatures. Then all the squid was gone, and so were the stingrays.

Classical conditioning also applies to humans, even babies. For example, Elan buys formula in blue canisters for their six-month-old daughter, Angelina. Whenever Elan takes out a formula container, Angelina gets excited, tries to reach toward the food, and most likely salivates. Why does Angelina get excited when she sees the formula canister? What are the UCS, CS, UCR, and CR here?

So far, all of the examples have involved food, but classical conditioning extends beyond the basic need to be fed. Consider our earlier example of a dog whose owners install an invisible electric dog fence. A small electrical shock (unconditioned stimulus) elicits discomfort (unconditioned response). When the unconditioned stimulus (shock) is paired with a neutral stimulus (the edge of a yard), the dog associates the discomfort (unconditioned response) with the edge of the yard (conditioned stimulus) and stays within the set boundaries. In this example, the edge of the yard elicits fear and anxiety in the dog. Fear and anxiety are the conditioned response.

Watch this video clip from the television show, The Office , for a humorous look at conditioning in which Jim conditions Dwight to expect a breath mint every time Jim’s computer makes a specific sound.

General Processes in Classical Conditioning

Now that you know how classical conditioning works and have seen several examples, let’s take a look at some of the general processes involved. In classical conditioning, the initial period of learning is known as acquisition , when an organism learns to connect a neutral stimulus and an unconditioned stimulus. During acquisition, the neutral stimulus begins to elicit the conditioned response, and eventually the neutral stimulus becomes a conditioned stimulus capable of eliciting the conditioned response by itself. Timing is important for conditioning to occur. Typically, there should only be a brief interval between presentation of the conditioned stimulus and the unconditioned stimulus. Depending on what is being conditioned, sometimes this interval is as little as five seconds (Chance, 2009). However, with other types of conditioning, the interval can be up to several hours.

Taste aversion is a type of conditioning in which an interval of several hours may pass between the conditioned stimulus (something ingested) and the unconditioned stimulus (nausea or illness). Here’s an example. Harry went to the carnival. He ate a lot of cotton candy and later that night was very sick and threw up. The next day, his friend offered him a piece of candy. He put it into his mouth and started to feel sick and had to spit it out. The unconditioned stimulus is eating too much cotton candy. The unconditioned response is getting sick and throwing up. The conditioned stimulus is the sugary flavor and the conditioned response is Harry feeling nauseous at the taste of sugar.

How does this occur—conditioning based on a single instance and involving an extended time lapse between the event and the negative stimulus? Research into taste aversion suggests that this response may be an evolutionary adaptation designed to help organisms quickly learn to avoid harmful foods (Garcia & Rusiniak, 1980; Garcia & Koelling, 1966). Not only may this contribute to species survival via natural selection, but it may also help us develop strategies for challenges such as helping cancer patients through the nausea induced by certain treatments (Holmes, 1993; Jacobsen et al., 1993; Hutton, Baracos, & Wismer, 2007; Skolin et al., 2006). Garcia and Koelling (1966) showed not only that taste aversions could be conditioned, but also that there were biological constraints to learning. In their study, separate groups of rats were conditioned to associate either a flavor with illness, or lights and sounds with illness. Results showed that all rats exposed to flavor-illness pairings learned to avoid the flavor, but none of the rats exposed to lights and sounds with illness learned to avoid lights or sounds. This added evidence to the idea that classical conditioning could contribute to species survival by helping organisms learn to avoid stimuli that posed real dangers to health and welfare.

Robert Rescorla demonstrated how powerfully an organism can learn to predict the UCS from the CS. Take, for example, the following two situations. Ari’s dad always has dinner on the table every day at 6:00. Soraya’s mom switches it up so that some days they eat dinner at 6:00, some days they eat at 5:00, and other days they eat at 7:00. For Ari, 6:00 reliably and consistently predicts dinner, so Ari will likely start feeling hungry every day right before 6:00, even if he's had a late snack. Soraya, on the other hand, will be less likely to associate 6:00 with dinner, since 6:00 does not always predict that dinner is coming. Rescorla, along with his colleague at Yale University, Allan Wagner, developed a mathematical formula that could be used to calculate the probability that an association would be learned given the ability of a conditioned stimulus to predict the occurrence of an unconditioned stimulus and other factors; today this is known as the Rescorla-Wagner model (Rescorla & Wagner, 1972)

Once we have established the connection between the unconditioned stimulus and the conditioned stimulus, how do we break that connection and get the dog, cat, or child to stop responding? In Tiger’s case, imagine what would happen if you stopped using the electric can opener for her food and began to use it only for human food. Now, Tiger would hear the can opener, but she would not get food. In classical conditioning terms, you would be giving the conditioned stimulus, but not the unconditioned stimulus. Pavlov explored this scenario in his experiments with dogs: sounding the tone without giving the dogs the meat powder. Soon the dogs stopped responding to the tone. Extinction is the decrease in the conditioned response when the unconditioned stimulus is no longer presented with the conditioned stimulus. When presented with the conditioned stimulus alone, the dog, cat, or other organism would show a weaker and weaker response, and finally no response. In classical conditioning terms, there is a gradual weakening and disappearance of the conditioned response.

What happens when learning is not used for a while—when what was learned lies dormant? As we just discussed, Pavlov found that when he repeatedly presented the bell (conditioned stimulus) without the meat powder (unconditioned stimulus), extinction occurred; the dogs stopped salivating to the bell. However, after a couple of hours of resting from this extinction training, the dogs again began to salivate when Pavlov rang the bell. What do you think would happen with Tiger’s behavior if your electric can opener broke, and you did not use it for several months? When you finally got it fixed and started using it to open Tiger’s food again, Tiger would remember the association between the can opener and her food—she would get excited and run to the kitchen when she heard the sound. The behavior of Pavlov’s dogs and Tiger illustrates a concept Pavlov called spontaneous recovery : the return of a previously extinguished conditioned response following a rest period ( Figure 6.7 ).

Of course, these processes also apply in humans. For example, let’s say that every day when you walk to campus, an ice cream truck passes your route. Day after day, you hear the truck’s music (neutral stimulus), so you finally stop and purchase a chocolate ice cream bar. You take a bite (unconditioned stimulus) and then your mouth waters (unconditioned response). This initial period of learning is known as acquisition, when you begin to connect the neutral stimulus (the sound of the truck) and the unconditioned stimulus (the taste of the chocolate ice cream in your mouth). During acquisition, the conditioned response gets stronger and stronger through repeated pairings of the conditioned stimulus and unconditioned stimulus. Several days (and ice cream bars) later, you notice that your mouth begins to water (conditioned response) as soon as you hear the truck’s musical jingle—even before you bite into the ice cream bar. Then one day you head down the street. You hear the truck’s music (conditioned stimulus), and your mouth waters (conditioned response). However, when you get to the truck, you discover that they are all out of ice cream. You leave disappointed. The next few days you pass by the truck and hear the music, but don’t stop to get an ice cream bar because you’re running late for class. You begin to salivate less and less when you hear the music, until by the end of the week, your mouth no longer waters when you hear the tune. This illustrates extinction. The conditioned response weakens when only the conditioned stimulus (the sound of the truck) is presented, without being followed by the unconditioned stimulus (chocolate ice cream in the mouth). Then the weekend comes. You don’t have to go to class, so you don’t pass the truck. Monday morning arrives and you take your usual route to campus. You round the corner and hear the truck again. What do you think happens? Your mouth begins to water again. Why? After a break from conditioning, the conditioned response reappears, which indicates spontaneous recovery.

Acquisition and extinction involve the strengthening and weakening, respectively, of a learned association. Two other learning processes—stimulus discrimination and stimulus generalization—are involved in determining which stimuli will trigger learned responses. Animals (including humans) need to distinguish between stimuli—for example, between sounds that predict a threatening event and sounds that do not—so that they can respond appropriately (such as running away if the sound is threatening). When an organism learns to respond differently to various stimuli that are similar, it is called stimulus discrimination . In classical conditioning terms, the organism demonstrates the conditioned response only to the conditioned stimulus. Pavlov’s dogs discriminated between the basic tone that sounded before they were fed and other tones (e.g., the doorbell), because the other sounds did not predict the arrival of food. Similarly, Tiger, the cat, discriminated between the sound of the can opener and the sound of the electric mixer. When the electric mixer is going, Tiger is not about to be fed, so she does not come running to the kitchen looking for food. In our other example, Moisha, the cancer patient, discriminated between oncologists and other types of doctors. She learned not to feel ill when visiting doctors for other types of appointments, such as her annual physical.

On the other hand, when an organism demonstrates the conditioned response to stimuli that are similar to the condition stimulus, it is called stimulus generalization , the opposite of stimulus discrimination. The more similar a stimulus is to the condition stimulus, the more likely the organism is to give the conditioned response. For instance, if the electric mixer sounds very similar to the electric can opener, Tiger may come running after hearing its sound. But if you do not feed her following the electric mixer sound, and you continue to feed her consistently after the electric can opener sound, she will quickly learn to discriminate between the two sounds (provided they are sufficiently dissimilar that she can tell them apart). In our other example, Moisha continued to feel ill whenever visiting other oncologists or other doctors in the same building as her oncologist.

Behaviorism

John B. Watson , shown in Figure 6.8 , is considered the founder of behaviorism. Behaviorism is a school of thought that arose during the first part of the 20th century, which incorporates elements of Pavlov’s classical conditioning (Hunt, 2007). In stark contrast with Freud, who considered the reasons for behavior to be hidden in the unconscious, Watson championed the idea that all behavior can be studied as a simple stimulus-response reaction, without regard for internal processes. Watson argued that in order for psychology to become a legitimate science, it must shift its concern away from internal mental processes because mental processes cannot be seen or measured. Instead, he asserted that psychology must focus on outward observable behavior that can be measured.

Watson’s ideas were influenced by Pavlov’s work. According to Watson, human behavior, just like animal behavior, is primarily the result of conditioned responses. Whereas Pavlov’s work with dogs involved the conditioning of reflexes, Watson believed the same principles could be extended to the conditioning of human emotions (Watson, 1919).

In 1920, while chair of the psychology department at Johns Hopkins University, Watson and his graduate student, Rosalie Rayner, conducted research on a baby nicknamed Little Albert. Rayner and Watson’s experiments with Little Albert demonstrated how fears can be conditioned using classical conditioning. Through these experiments, Little Albert was exposed to and conditioned to fear certain things. Initially he was presented with various neutral stimuli, including a rabbit, a dog, a monkey, masks, cotton wool, and a white rat. He was not afraid of any of these things. Then Watson, with the help of Rayner, conditioned Little Albert to associate these stimuli with an emotion—fear. For example, Watson handed Little Albert the white rat, and Little Albert enjoyed playing with it. Then Watson made a loud sound, by striking a hammer against a metal bar hanging behind Little Albert’s head, each time Little Albert touched the rat. Little Albert was frightened by the sound—demonstrating a reflexive fear of sudden loud noises—and began to cry. Watson repeatedly paired the loud sound with the white rat. Soon Little Albert became frightened by the white rat alone. In this case, what are the UCS, CS, UCR, and CR? Days later, Little Albert demonstrated stimulus generalization—he became afraid of other furry things: a rabbit, a furry coat, and even a Santa Claus mask ( Figure 6.9 ). Watson had succeeded in conditioning a fear response in Little Albert, thus demonstrating that emotions could become conditioned responses. It had been Watson’s intention to produce a phobia—a persistent, excessive fear of a specific object or situation— through conditioning alone, thus countering Freud’s view that phobias are caused by deep, hidden conflicts in the mind. However, there is no evidence that Little Albert experienced phobias in later years. While Watson’s research provided new insight into conditioning, it would be considered unethical by today’s standards.

View scenes from this video on John Watson’s experiment in which Little Albert was conditioned to respond in fear to furry objects to learn more.

As you watch the video, look closely at Little Albert’s reactions and the manner in which Watson and Rayner present the stimuli before and after conditioning. Based on what you see, would you come to the same conclusions as the researchers?

Advertising and Associative Learning

Advertising executives are pros at applying the principles of associative learning. Think about the car commercials you have seen on television. Many of them feature an attractive model. By associating the model with the car being advertised, you come to see the car as being desirable (Cialdini, 2008). You may be asking yourself, does this advertising technique actually work? According to Cialdini (2008), men who viewed a car commercial that included an attractive model later rated the car as being faster, more appealing, and better designed than did men who viewed an advertisement for the same car minus the model.

Have you ever noticed how quickly advertisers cancel contracts with a famous athlete following a scandal? As far as the advertiser is concerned, that athlete is no longer associated with positive feelings; therefore, the athlete cannot be used as an unconditioned stimulus to condition the public to associate positive feelings (the unconditioned response) with their product (the conditioned stimulus).

Now that you are aware of how associative learning works, see if you can find examples of these types of advertisements on television, in magazines, or on the Internet.

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.

Access for free at https://openstax.org/books/psychology-2e/pages/1-introduction

• Authors: Rose M. Spielman, William J. Jenkins, Marilyn D. Lovett
• Publisher/website: OpenStax
• Book title: Psychology 2e
• Publication date: Apr 22, 2020
• Location: Houston, Texas
• Book URL: https://openstax.org/books/psychology-2e/pages/1-introduction
• Section URL: https://openstax.org/books/psychology-2e/pages/6-2-classical-conditioning

© Jun 26, 2024 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.

Ivan Pavlov and the Theory of Classical Conditioning

Pavlov's discovery was that environmental events that previously had no relation to a given reflex (such as a bell sound) could, through experience, trigger a reflex (salivation). This kind of learnt response is called conditioned reflex, and the process whereby dogs or humans learn to connect a stimulus to a reflex is called conditioning.

Animals generally learn to associate stimuli that are relevant to their survival. Food aversion is an example of a natural conditioned reflex. If an animal eats something with a distinctive vanilla taste and then eats a tasteless poison that leads to nausea, the animal will not be particularly eager to eat vanilla-flavoured food the next time. Linking nausea to taste is an evolutionarily successful strategy, since animals that failed to learn their lesson did not last very long.

Why were Pavlov's findings given so much acknowledgment?

Pavlov's description on how animals (and humans) can be trained to respond in a certain way to a particular stimulus drew tremendous interest from the time he first presented his results. His work paved the way for a new, more objective method of studying behavior.

So-called Pavlovian training has been used in many fields, with anti-phobia treatment as but one example. An important principle in conditioned learning is that an established conditioned response (salivating in the case of the dogs) decreases in intensity if the conditioned stimulus (bell) is repeatedly presented without the unconditioned stimulus (food). This process is called extinction.

Conditioning forms the basis of much of learned human behavior. Nowadays, this knowledge has also been exploited by commercial advertising. An effective commercial should be able to manipulate the response to a stimulus (like seeing a product's name) which initially does not provoke any feeling. The objective is to train people to make the "false" connection between positive emotions (e.g. happiness or feeling attractive) and the particular brand of consumer goods being advertised.

Pavlov's prize

Until Pavlov started to scrutinize this field, our knowledge of how food was digested in the stomach, and what mechanisms were responsible for regulating this, were quite foggy.

In order to understand the process, Pavlov developed a new way of monitoring what was happening. He surgically made fistulas in animals' stomachs, which enabled him to study the organs and take samples of body fluids from them while they continued to function normally.

By Lotta Fredholm, Science Journalist

More about Nobel Laureate Ivan Pavlov

Play the Pavlov's Dog Game

First published 15 May 2001

Privacy Policy

Terms of use

The Nobel Prize

Copyright © Nobel Prize Outreach AB 2024

• List of Theories
• Privacy Policy
• Opt-out preferences

Classical Conditioning – The Pavlov’s Dogs Experiment

Have you ever heard a song or tune from your childhood and felt an instant rush of nostalgia or happiness? That tune and the happiness/nostalgic feeling are interconnected by association, which we call Classical Conditioning.

Classical Conditioning is a psychological phenomenon in which one learns by pairing two or more stimuli to create an association. It is the process of creating a link between a conditioned stimulus and a conditioned response.

Who Discovered Classical Conditioning ?

The phenomenon of Classical Conditioning was discovered by Ivan Pavlov. Ivan Pavlov was a Russian Physiologist who was interested in understanding canine physiology and was especially interested in their digestive systems.

He began to observe dogs and their eating patterns to identify when they begin to salivate. Through his observations, he believed that dogs begin to salivate when they heard the bell that was rung before the food was presented.

To prove his theory, Pavlov built a machine that would accurately determine and measure the amount of saliva produced when the food was presented. Thus began the infamous Pavlov’s dogs experiment.

What is the Pavlov’s Dogs Experiment ?

Pavlov initially placed the food in front of the dog and recorded the level of salivation. He did this a couple of times to measure and assess why the dog was salivating.

After the first couple of trials, he began to ring a bell. He would ring the bell and wait approximately 5 seconds before presenting the food. The dogs continued to salivate only when the food was present. However, after repetitive exposure to the bell and the food, the dogs began to salivate upon hearing the bell.

This means that the dog began to associate the bell with food. This leads to salivation when hearing the bell.

Core Concept Of Classical Conditioning

This experiment led to the discovery of a type of learning called Classical Conditioning (as termed by Pavlov). The experiment was conducted in 1906 and was a major catalyst in the development and understanding of learning and behaviour theories.

The experiment consists of 4 different elements. These are:

1) Unconditioned Stimulus

This is a certain object or stimulus that triggers an automatic/involuntarily bodily response. This is an unconscious process and has not been previously learnt. In this case, the food is considered to be the unconditioned stimuli.

For example, for a student, the smell of the food from the mess/canteen is considered to be the unconditioned stimuli.

2) Unconditional Response

This is the automatic and involuntary response that occurs when presented with the object or the stimulus. This response is generally unlearnt and usually occurs due to the processes of the Central Nervous System (CNS). In this case, the salivation of the dogs is the Unconditioned Response.

For example, the hunger and salivation of the student are considered to be the unconditioned response.

3) Conditioned Stimulus

This is also known as the Neutral Stimulus. This stimulus is presented repeatedly until the association between the object and the response is formed. If the object is repeatedly presented (in this case the food), it will start to evoke the same response. In this case, the bell is considered to be the conditioned stimulus.

For example, the lunch bell is paired with the smell of the food. Hence the bell is associated with lunchtime. Therefore, the bell becomes the conditioned stimulus.

4) Conditioned Response

This is the response obtained after repeated exposure to the conditioned stimulus (which is the bell). This is the response that occurs once the stimulus and response have been associated. The conditioned response is salivating upon hearing the bell.

For example, the bell is now associated with the food from the mess/canteen. Hence, the student may get hungry/salivate upon hearing the sound of the bell. This indicates that classical conditioning has occurred.

Common Example – Conditioning Theory Of Learning

A great example of this is when you smell your mom’s perfume. You may have grown up used to the smell of your mom’s perfume. The perfume reminds you of your mother and the great times you shared when you were growing up. You are exposed to the perfume several times while growing up; you begin to associate it with happiness.

Several years later, if you catch a sniff of the perfume in a supermarket, you may associate it with happiness without actually consciously thinking of your childhood or your mother. This is due to learning by association otherwise known as Classical Conditioning.

There are three other aspects that we must understand and take into account when learning about classical conditioning. They are:

a) Extinction

This is a phenomenon in which the conditioned stimulus (i.e. the bell) is presented excessively without the unconditioned stimulus (i.e. dog food). This overexposure results in the process of unlearning. Eventually, the bell will no longer result in a conditioned response.

For example, while training children to potty train, the parents might give a reward every time the child uses the toilet. However, over time as the child continues to use the toilet, the parent will stop providing the rewards. Due to the overexposure, the child will eventually continue the behavior without association.

b) Generalization

This occurs when the conditioned stimulus is generalized, and therefore causes a conditioned response. For example, the dog may generalize the sound of other bells and may begin to salivate.

This can be found in the case of Little Albert. He was taught to fear a white rabbit using classical conditioning. However, he began to generalize that phobia to other objects of similar shape, size and colour. He also began to fear other objects such as mice, hamsters etc. This is known as generalization.

c) Discrimination

This is the opposite response to Generalization. This occurs when the person/ animal can discriminate between different stimuli and therefore will not produce the same reaction to the different stimuli.

This can be seen when one has a very certain phobia. For example, a person who has a phobia of cockroaches may not have a phobia of spiders or other insects even though they are similar.

What are the applications of Classical Conditioning in Psychology ?

Classical Conditioning has helped several psychologists understand how people learn and behave. Classical Conditioning helped pave the way for understanding certain pathological conditions (i.e. phobias, drug dependency and aversions) and their treatments. These include:

a) Phobias and Systematic Desensitization

A famous experiment conducted by John B Watson called Little Albert helps us understand how phobias are formed. Watson used the same method of classical conditioning to instil fear in a little boy named Albert. Albert was initially presented with a small rat for the first few trials.

After the first few trials, the rat was presented with a loud noise. Although Albert was initially not afraid of the rat, the association between the rat and the loud noise was formed. This resulted in causing him extreme fear when he saw the rat. This resulted in Albert having a phobia of rats.

Classical Conditioning can also be used to help get ready for phobias. This is usually done using a method of Systematic Desensitization. This treatment works by creating a hierarchy of fear. The client will identify and rank their fears from lowest to highest.

For example, a client who has a fear of lizards may feel fear at 10% while talking about them, 30% fear while looking at a picture, 50% watching a video of a lizard and 70% of fear while one is in the room.

The therapist then begins to work up the hierarchy while pairing deep breathing exercises.

For example, the therapist shows the client an image of a lizard and then guides them through deep breathing. This is repeated several times until the client no longer feels scared to see an image. They then move on to the next stage of the hierarchy.

This is what the hierarchy for herpetophobia (Fear of Lizards) would look like.

Vicarious Conditioning is the occurrence of developing fear and becoming conditioned due to watching someone else.

For example, if you watch your mother running away from a spider, you may also become conditioned into thinking that spiders are something that evokes fear. This may lead to arachnophobia later on.

b) Drug Dependency and Aversion Therapy

Drugs cause a feeling of “ecstasy” or a “high”. This feeling of high results in the user repeatedly using. The feeling of ecstasy and the substance become paired, thus the user will continue to use the substance. They may even become extremely dependent on it, resulting in an abuse disorder.

Aversion Therapy is a treatment method used to combat abuse disorder. This is behavioural therapy method in which there is a pairing between unwanted behaviour and discomfort.

For example, someone who is addicted to alcohol may be required to snap a rubber band on their wrist every time they think of alcohol.

c) Classical Conditioning and Attitude Formation

Classical Conditioning has shown a significant outcome in attitude formation. Classical Conditioning has shown the ability to determine and change a person’s attitude/ feelings towards a particular object.

For example, a child grows up seeing her mother react negatively to Native Americans. Every time her mother comes across someone of Native American descent, she gets angry. She begins to associate anger with the Native Americans. She may begin to view them negatively and may even grow up and treat them the same.

Hence, classical conditioning has affected her attitude towards a certain race. This is attitude formation.

Ivan Pavlov’s experimentation with learning and behaviour caused a ripple effect throughout the psychological community. It promoted the development of several other theories of learning. It also helped us understand human behaviour and helped in the evolution of treatment methods.

So next time you come across Pavlov and Classical Conditioning, I hope this article rings a bell.

Related Posts:

• Concept Of Emotional Intelligence (EI)- High And Low EQ
• Albert Bandura's Social Cognitive Theory - Explained
• Anger Management - Techniques, Tips And Therapy
• Types Of Thinking-Tips And Tricks To Improve Thinking Skill
• Conflict Management - Skills, Styles And Models
• Jean Piaget - Stages Of Cognitive Development

Good condition for me and I am waiting for the new one to you

Hey people!!!!! Good mood and good luck to everyone!!!!!

Leave a Comment

Next post: B.F. Skinner’s Theory of Operant Conditioning

Previous post: Cognitive Distortions And How CBT Helps To Overcome It ?

• Advertising, Public relations, Marketing and Consumer Behavior
• Business Communication
• Communication / General
• Communication Barriers
• Communication in Practice
• Communication Models
• Cultural Communication
• Development Communication
• Group Communication
• Intercultural Communication
• Interpersonal Communication
• Mass Communication
• Organisational Communication
• Political Communication
• Psychology, Behavioral And Social Science
• Technical Communication
• Visual Communication

Communication Theory

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• My Bibliography
• Collections
• Citation manager

Save citation to file

Email citation, add to collections.

• Create a new collection
• Add to an existing collection

Add to My Bibliography

Your saved search, create a file for external citation management software, your rss feed, classical conditioning, affiliations.

• 1 Cornell University
• 2 A.T. Still University
• 3 Touro University, Nevada
• 4 University Hospital Lewisham
• PMID: 29262194
• Bookshelf ID: NBK470326

Learning is the process by which new knowledge, behaviors, attitudes, and ideas are acquired. Learning can occur through both unconscious and conscious pathways. Classical conditioning is one of those unconscious learning methods and is the most straightforward way in which humans can learn. Classical conditioning is the process in which an automatic, conditioned response is paired with specific stimuli. Although Edwin Twitmyer published findings pertaining to classical conditioning one year earlier, the best-known and most thorough work on classical conditioning is accredited to Ivan Pavlov, a Russian physiologist born in the mid-1800s. Pavlov had such a great impact on the study of classical conditioning that it is often referred to as Pavlovian conditioning.

Pavlov’s Experiment

Classical conditioning was stumbled upon by accident. Pavlov was conducting research on the digestion of dogs when he noticed that the dogs’ physical reactions to food subtly changed over time. At first, the dogs would only salivate when the food was placed in front of them. However, later they salivated slightly before their food arrived. Pavlov realized that they were salivating at the noises that were consistently present before the food arrived; for example, the sound of a food cart is approaching.

To test his theory, Pavlov set up an experiment in which he rang a bell shortly before presenting food to the dogs. At first, the dogs elicited no response to the bells. However, eventually, the dogs began to salivate at the sound of the bell alone.

To understand classical conditioning, it is essential to be familiar with the following terms. A neutral stimulus is a stimulus that at first elicits no response. Pavlov introduced the ringing of the bell as a neutral stimulus. An unconditioned stimulus is a stimulus that leads to an automatic response. In Pavlov’s experiment, the food was the unconditioned stimulus. An unconditioned response is an automatic response to a stimulus. The dogs salivating for food is the unconditioned response in Pavlov’s experiment. A conditioned stimulus is a stimulus that can eventually trigger a conditioned response. In the described experiment, the conditioned stimulus was the ringing of the bell, and the conditioned response was salivation.

It is important to note that the neutral stimulus becomes the conditioned stimulus. Furthermore, it is important to realize that the unconditioned response and the conditioned response are the same except for which stimulus they are elicited by. In this case, salivation was the response, but the unconditioned response was triggered by food, whereas the conditioned response was triggered by the bell which indicated the coming of food.

Copyright © 2024, StatPearls Publishing LLC.

PubMed Disclaimer

Conflict of interest statement

Disclosure: Ibraheem Rehman declares no relevant financial relationships with ineligible companies.

Disclosure: Navid Mahabadi declares no relevant financial relationships with ineligible companies.

Disclosure: Terrence Sanvictores declares no relevant financial relationships with ineligible companies.

Disclosure: Chaudhry Rehman declares no relevant financial relationships with ineligible companies.

• Introduction
• Issues of Concern
• Clinical Significance
• Other Issues
• Enhancing Healthcare Team Outcomes
• Review Questions

Similar articles

• Chronic Recording During Learning. Sandler AJ. Sandler AJ. In: Nicolelis MAL, editor. Methods for Neural Ensemble Recordings. 2nd edition. Boca Raton (FL): CRC Press/Taylor & Francis; 2008. Chapter 7. In: Nicolelis MAL, editor. Methods for Neural Ensemble Recordings. 2nd edition. Boca Raton (FL): CRC Press/Taylor & Francis; 2008. Chapter 7. PMID: 21204449 Free Books & Documents. Review.
• Eponymy, obscurity, Twitmyer, and Pavlov. Coon DJ. Coon DJ. J Hist Behav Sci. 1982 Jul;18(3):255-62. doi: 10.1002/1520-6696(198207)18:3 3.0.co;2-y. J Hist Behav Sci. 1982. PMID: 6749963
• Pavlov's position toward Konorski and Miller's distinction between Pavlovian and motor conditioning paradigms. Windholz G, Wyrwicka W. Windholz G, et al. Integr Physiol Behav Sci. 1996 Oct-Dec;31(4):338-49. doi: 10.1007/BF02691437. Integr Physiol Behav Sci. 1996. PMID: 8982765
• Signalization and stimulus-substitution in Pavlov's theory of conditioning. García-Hoz V. García-Hoz V. Span J Psychol. 2003 Nov;6(2):168-76. doi: 10.1017/s113874160000531x. Span J Psychol. 2003. PMID: 14628703
• Pavlov as a psychologist. A reappraisal. Windholz G. Windholz G. Pavlov J Biol Sci. 1987 Jul-Sep;22(3):103-12. Pavlov J Biol Sci. 1987. PMID: 3309839 Review.
• Stussi Y, Ferrero A, Pourtois G, Sander D. Achievement motivation modulates Pavlovian aversive conditioning to goal-relevant stimuli. NPJ Sci Learn. 2019;4:4. - PMC - PubMed
• Amd M, Machado A, de Oliveira MA, Passarelli DA, De Rose JC. Effects of Nodal Distance on Conditioned Stimulus Valences Across Time. Front Psychol. 2019;10:742. - PMC - PubMed
• Totani Y, Aonuma H, Oike A, Watanabe T, Hatakeyama D, Sakakibara M, Lukowiak K, Ito E. Monoamines, Insulin and the Roles They Play in Associative Learning in Pond Snails. Front Behav Neurosci. 2019;13:65. - PMC - PubMed
• Pauli WM, Gentile G, Collette S, Tyszka JM, O'Doherty JP. Evidence for model-based encoding of Pavlovian contingencies in the human brain. Nat Commun. 2019 Mar 07;10(1):1099. - PMC - PubMed
• Hanley AW, Garland EL. Mindfulness training disrupts Pavlovian conditioning. Physiol Behav. 2019 May 15;204:151-154. - PubMed

Publication types

• Search in PubMed
• Search in MeSH
• Add to Search

Related information

Linkout - more resources, full text sources.

• NCBI Bookshelf

• Citation Manager

NCBI Literature Resources

MeSH PMC Bookshelf Disclaimer

The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Unauthorized use of these marks is strictly prohibited.

Pavlovian Conditioning: Ivan Pavlov’s Dogs Experiment

Ivan Petrovich Pavlov (1849-1936) lived during a golden age of scientific discovery.

Born into the Russian Empire, and known within his family for being intellectually curious and unusually energetic from a young age, Pavlov won the Nobel Prize in Physiology or Medicine in 1904 for his work on the physiology of digestion, making him the first Russian Nobel laureate. Despite this, Pavlov’s most well-known contribution to science was through his dogs experiments, which became the basis for Pavlovian conditioning (also known as classical conditioning).

In this article, I’m going to look into Pavlov’s dogs experiment, followed by a detailed look at Pavlovian conditioning and Pavlovian response, before moving on to a section on further reading for anyone interested in learning more about this field.

What is Pavlov’s Dogs Experiment?

Ivan Pavlov’s dogs experiment is an experiment that took place in the 1890s in which the Russian physiologist surgically implanted small tubes into the cheeks of dogs to measure the buildup of saliva that took place under a variety of conditions.

Pavlov’s dogs experiment came about as part of an accidental discovery. Pavlov had at the time been conducting research experiments into the dogs’ gastric systems. As part of this research, Pavlov and his assistants would enter the room where the dogs were housed with a variety of edible and non-edible items, with the intention of measuring the amount of saliva that each dog produced when each item was placed in front of them.

Pavlov prediction that the dogs would salivate when presented with edible items was soon proved correct. This represents an unconditioned response in the animals, in which the sight and smell of the food causes them to salivate. Pavlov couldn’t have predicted what happened next.

A Pavlovian Response

While conducting his gastric experiment, Pavlov began to notice something peculiar. He noticed that the dogs would begin salivating not when food was placed in front of them, but when they heard the footsteps of one of Pavlov’s assistants coming down the hall to bring the food to them.

Pavlov soon realized that he could teach his dogs to associate almost any sound, item, or event with the reward of food. To put this another way, it became clear that salivation was a learned response. The most famous item used in Pavlov’s dogs experiment was that of a bell—Pavlov or one of his assistants would ring a bell before feeding his dogs. Soon enough, the single act of ringing the bell would be enough for the dogs to associate this seemingly neutral act with the promise of food.

Pavlovian conditioning was born, and Pavlov’s dogs experiment became his life’s work.

Pavlovian Conditioning

With its genesis in Pavlov’s dogs experiment, Pavlovian conditioning is defined as a form of behavioral psychology (or behaviorism) in which an animal, or human, can be conditioned to respond in a certain way to a stimulus that, had it not been conditioned, should in no way be associated with the act in question.

Let me show you what I mean:

An Unconditioned Stimulus Causes an Unconditioned Response

Prior to Pavlov’s experiment and the discovery of Pavlovian conditioning, it was well-known in the scientific world that an unconditioned stimulus causes an unconditioned response.

An example of this in terms of Pavlov’s dogs experiment would be the food being placed directly in front of the dogs, causing them to salivate. The unconditioned stimulus in this example is the food, and the unconditioned response is the salivation. Pavlov’s dogs’ response (to salivate) was unconditioned because they didn’t need to be trained to respond to the food in this way—it simply happened naturally.

A Neutral Stimulus Causes No Response

In the same way that an unconditioned stimulus causes an unconditioned response, Pavlov confirmed the commonly agreed-upon theory that a neutral stimulus causes no response.

An example of this in terms of Pavlov’s dogs experiment would be the act of Pavlov or one of his assistants ringing a bell before feeding the dogs, before they had taken the time to condition the bell as a stimulus to the food. If they were to ring the bell while it was still a neutral stimulus, no response, conditioned or unconditioned, would have occurred. (Depending on how loud the bell was, the dogs may have been startled the first few times it rang, but this is superfluous to the experiment.)

A Conditioned Stimulus Causes a Conditioned Response

Finally, Pavlov discovered through the course of his experiment that a conditioned stimulus causes a conditioned response.

An example of this in terms of Pavlov’s dogs experiment would be the act of Pavlov or one of his assistants ringing a bell before feeding the dogs, after they have already conditioned the sound of the bell to the promise of food. In this case, the sound of the bell has graduated from being a neutral stimulus to a conditioned stimulus, therefore the dogs’ response (to salivate) became a conditioned response.

Further Reading

In this article I have introduced Pavlov’s dogs experiment and Pavlovian conditioning. The field of classical conditioning and behavioral psychology is vast, and if you found this article interesting I recommend you take a look at some of the following:

• Behaviorism, Stanford Encyclopedia of Philosophy
• A Short History of Behaviorism, Washington State University
• Behavioral Principles: Classical Conditioning, St. Cloud University

Ivan Pavlov’s dogs experiment and the birth of Pavlovian conditioning was an instrumental scientific discovery at its time that deserves the acclaim and spirited conversation that it entails to this day.

If you’re interested in hearing more from me, be sure to subscribe to my free email newsletter , and if you enjoyed this article, please share it on social media, link to it from your website, or bookmark it so you can come back to it often. ∎

Benjamin Spall

You might also like....

How Diffusion of Responsibility Alters Group Psychology

The Bystander Effect: The Psychology Behind a Social Phenomenon

Consequentialism Ethics: A Brief Introduction

• Bipolar Disorder
• Therapy Center
• When To See a Therapist
• Types of Therapy
• Best Online Therapy
• Best Couples Therapy
• Managing Stress
• Sleep and Dreaming
• Understanding Emotions
• Self-Improvement
• Healthy Relationships
• Student Resources
• Personality Types
• Sweepstakes
• Guided Meditations
• Verywell Mind Insights
• 2024 Verywell Mind 25
• Mental Health in the Classroom
• Editorial Process
• Meet Our Review Board
• Crisis Support

The Unconditioned Stimulus in Classical Conditioning

Definition and Examples of the UCS

Tara Moore / Getty Images

Examples of Unconditioned Stimuli

The neutral stimulus.

• Unconditioned vs. Conditioned Stimuli

Timing of Learned Behavior

Types of classical conditioning.

In the learning process known as  classical conditioning , the unconditioned stimulus (UCS) is one that unconditionally, naturally, and automatically triggers a response . In other words, the response takes place without any prior learning.

Contrast this with the conditioned stimulus, which only prompts a response after a person or animal has learned to associate the stimulus with a certain response.

Unconditioned stimuli are all around us. Think about:

• The smell of a favorite food, which immediately makes you feel hungry
• A feather tickling your nose, which causes you to sneeze
• An onion's smell as you cut it, which makes your eyes water
• Pollen from grass and flowers, which causes you to sneeze
• A unexpected loud bang, which causes you to flinch

In each of these examples, the unconditioned stimulus naturally triggers an unconditioned response or reflex. You don't have to learn to respond to the unconditioned stimulus; it occurs automatically.

The Unconditioned Stimulus in Pavlov's Experiment

In Ivan Pavlov's classic experiment with dogs, Pavlov and his assistants showed the dogs edible and non-edible items and measured saliva production with each. Salivation occurred automatically and without the dogs' conscious effort when they smelled the food.

This response required no learning. The food was an unconditioned stimulus because it prompted a reflexive response.

The Little Albert Experiment

Building on Pavlov's work, behaviorist  John B. Watson  and graduate student Rosalie Rayner conducted what came to be known as " the Little Albert experiment ." The research showed that emotional reactions could be classically conditioned in people.

Watson and Rayner exposed a 9-month-old child, Albert, to a white rat, a rabbit, a monkey, masks, and burning newspapers and observed the boy's reactions. He showed no fear of them at first.

But after Watson began making a loud noise—an unconditioned stimulus that provoked Albert's crying—whenever he showed Albert the white rat, Albert became frightened whenever he saw the white rat. Because he'd learned to associate the white rat with a noise he feared, he ultimately reacted with fear to the rat as well. The rat, once a neutral stimulus, had become a conditioned stimulus.

For the purposes of classical conditioning or learning, you need a neutral stimulus as well as an unconditioned stimulus. In other words, for conditioning to take place, you must first start by pairing a neutral stimulus with an unconditioned stimulus.

A neutral stimulus doesn't trigger any particular response at first, but when used together with an unconditioned stimulus, it can effectively stimulate learning, eventually becoming a conditioned stimulus. A good example of a neutral stimulus is a sound or a song.

When it is initially presented, the neutral stimulus has no effect on behavior. As it is repeatedly paired with an unconditioned stimulus, it will begin to cause the same response as the UCS.

For example, the assistants in Pavlov's experiment initially elicited no salivation and therefore were neutral stimuli. Likewise, the sound of a squeaky door opening is initially a neutral stimulus. If that sound is repeatedly paired with an unconditioned stimulus, such as feeding your cat, that sound will eventually come to trigger a change in your cat's behavior. Once an association has been formed, your cat may react as if it is being fed every time it hears the squeaky door open.

Unconditioned Stimulus vs. Conditioned Stimulus

An unconditioned stimulus causes a response without any prior learning on the part of the subject. The response is automatic and occurs without thought. In contrast, a conditioned stimulus produces a reaction only after the subject has learned to associate it with a given outcome.

In Pavlov's experiments, the dogs learned to salivate when they saw the assistants' white lab coats because they'd formed an association between the assistants and the food they presented, The salivary response to the assistants was not an automatic, physiological process, but a learned one. The presence of the assistants, initially a neutral stimulus, became a conditioned stimulus.

Throughout the classical conditioning process, a number of factors can influence how quickly associations are learned. The length of time that passes between presenting the initially neutral stimulus and the unconditioned stimulus is one of the most important factors in whether learning occurs.

The timing of how the neutral stimulus and the unconditioned stimulus are presented is what influences whether or not an association will be formed, a principle that is known as the theory of contiguity.

In Pavlov's experiment, the sound of a buzzer was initially a neutral stimulus, while the smell of food was an unconditioned stimulus. Presenting the tone close to presenting the smell of food resulted in a stronger association. Ringing the buzzer, the neutral stimulus, long before the unconditioned stimulus led to a much weaker or even nonexistent association.

Different types of conditioning may use different timing or order between the neutral stimulus and the UCS.

• In simultaneous conditioning , the neutral stimulus is presented at the exact time as the unconditioned stimulus. This type of conditioning leads to weak learning.
• In backward conditioning , the unconditioned stimulus is given first, and the neutral stimulus is presented afterward. This type of conditioning also tends to result in weak learning.
• In trace conditioning , the neutral stimulus is presented briefly and then stopped, then the unconditioned stimulus is presented. This type of conditioning produces good results.
• In delayed conditioning , the neutral stimulus is presented and continues while the unconditioned stimulus is offered. This type of conditioning produces the best results.

Beck HP, Levinson S, Irons G.  Finding Little Albert: A journey to John B. Watson's infant laboratory .  Am Psychol.  2009;64(7):605-14. doi:10.1037/a0017234

Boakes RA, Costa DSJ. Temporal contiguity in associative learning: Interference and decay from an historical perspective . J Exp Psychol Anim Learn Cogn. 2014;40(4):381-400. doi:10.1037/xan0000040

Prével A, Rivière V, Darcheville J, Urcelay GP. Conditioned reinforcement and backward association . Learn Motivat. 2016;56:38-47. doi:10.1016/j.lmot.2016.09.004

Pavlov I. Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex . Oxford University Press.

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