What Is the Classical Conditioning Theory? 6 Real-Life Examples

Classic Conditioning TheoryUntil the 1950s, behaviorism was the dominant school of thought in psychology.

It attempted to explain behavior based on the effects of the environment and learning rather than innate or inherited factors (Gross, 2020).

Classical conditioning theory, discovered by Russian physiologist and Nobel prize winner Ivan Pavlov, was central to behaviorism’s success.

Pavlovian conditioning, as it was sometimes known, focused on the role of unconscious learning and the process of pairing an automatic, previously unconditioned response with a new, neutral stimulus (Rehman, Mahabadi, Sanvictores, & Rehman, 2020).

This article introduces the theory, along with real-life examples, before discussing its strengths and weaknesses.

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What Is the Classical Conditioning Theory?

Behaviorists focus on the effect of the environment on human and non-human behavior. Their focus is on learning, particularly conditioning, to the exclusion of inherited, innate factors (Gross, 2020).

To the behaviorist, observable behavior is considered a response to stimuli (environmental events). In classical conditioning, as opposed to operant conditioning, “the stimulus is seen as triggering a response in a predictable, automatic way” (Gross, 2020). It is often referred to as stimulus and response psychology.

Conditioning forms an association between the stimulus and the response.


Who was Ivan Pavlov?

In 1904, Ivan Pavlov was awarded the prestigious Nobel prize for his work on digestion in dogs. Despite his focus on animal physiology, his research had a profound effect on the study of human psychology.

By stumbling across classical conditioning (sometimes referred to as Pavlovian conditioning) by accident, he significantly influenced the field of behaviorism (Gross, 2020; Rehman et al., 2020).

Even though Edwin Twitmyer had published related work a year earlier, Pavlov is widely recognized and best known for his thorough work on classical conditioning.

While it seems unlikely that experiments on dogs could have such a far-reaching and long-lasting impact on psychology, that changed when Pavlov (1927) noticed he could change how dogs behaved and reacted to food (Rehman et al., 2020).


Pavlov’s dog experiment

During Pavlov’s (1927) experiments into digestion in dogs, he noticed that they typically started to salivate before being given food. Not only that, even seeing the feeding bucket or hearing the lab assistant’s footsteps was enough to initiate a response (Gross, 2020).

Such observations led to the study of what we now call classical conditioning and the recognition that a stimulus such as a sound or an image with no particular meaning could pair with another stimulus to produce a response – in this case, salivating (Gross, 2020).


How Does It Work? A Model & Diagram

Stages of conditioning

3 Stages of classical conditioning

Based on his observations, Pavlov learned that new, neutral stimuli could be paired with existing stimuli to produce a response, as follows (modified from Gross, 2020):

  • Before conditioning (or learning) – The sound of a bell does not make a dog salivate, but food does.

The food is an unconditioned stimulus (UCS) that results in an automatic, biologically built-in unconditioned response (UCR) – in this case, salivating.

Unconditioned refers to the fact that it is not conditional on being paired with anything.

  • During conditioning – The bell and the food are paired.

The bell is a conditioned stimulus (CS).

Until it is paired, the bell has no effect on the UCR (salivating). It is neutral.

“It only produces a response on the condition that it is paired with the [food]” (Gross, 2020, p. 173).

  • After conditioning – When the bell (CS) has been paired with the food (UCS) enough times, it makes the dog salivate (now a CR).

The conditioned stimulus leads to a conditioned response.

And it works, not only with bells but also lights, metronomes, and even geometric shapes.

The degree of response can also be varied depending on how the CS is presented. The timing involved in classical conditioning is crucial and typically involves one of the following (Gross, 2020):

  • The CS occurs with differing delays before the UCS.
  • The CS is presented after the UCS.
  • The CS and UCS are presented together.
  • The CS is presented and removed before the UCS arrives.

The first option, where the CS is presented a half-second before the UCS, usually results in the strongest learning (Gross, 2020).

The following diagram represents the three steps involved in classical conditioning: before, during, and after conditioning (modified from Gross, 2020):

Stage 1. Before conditioning (or learning) – The bell does not produce salivation.

Classical Conditioning Stage 1

Stage 2. During conditioning – CS (bell) and UCS (food) are paired.

Classical Conditioning Stage 2

Stage 3. After learning – Bell produces salivation.

Classical Conditioning Stage 3


Key Concepts of Classical Conditioning

Classical conditioning includes other factors worthy of consideration. The following concepts help clarify some of the additional subtleties in Pavlov’s research and the classical conditioning theory.


First and second-order conditioning

While Pavlov proved it was possible to pair a conditioned stimulus (a bell) with an unconditioned stimulus (food), known as first-order conditioning, he also found that he could go one stage further (Gross, 2020).

Pavlov could subsequently pair the bell or any other stimulus with something unique and previously unseen, such as a black square. After 10 pairings, the dog would begin salivating at the sight of the square even though it had never been paired directly with the food. This indirect association is known as second-order conditioning.

Conditioning was beginning to look increasingly complex. However, there were limits. Pavlov (1927) found that dogs could not go beyond third or fourth-order conditioning (Gross, 2020).


Generalization and discrimination

Pavlov also found that even though a researcher may have trained a dog with one particular bell, other bells could still produce the same effect even if they differed in pitch. The spontaneous transfer of conditioned response is known as generalization (Pavlov, 1927).

However, the further away the new stimulus got from the original, the weaker the conditioned response; eventually, it stopped altogether. The limit to generalization is known as discrimination (Gross, 2020).

Pavlov subsequently used discrimination training to teach dogs to differentiate between stimuli of the same type that differed by a single factor, such as pitch (Gross, 2020).



Once conditioned, if the conditioned stimulus continued to sound, but no food appeared, the conditioned response (salivating) reduced until it stopped (Gross, 2020).

However, after a short break, the dog’s response spontaneously recovered with no further pairing.

Therefore, extinction as it is known, does not remove the original learning; it temporarily suppresses it.



Though more relevant to operant conditioning than classical conditioning, reinforcement is an essential aspect of behaviorism and can come in two flavors.

Positive reinforcement involves presenting something favorable to encourage or reward behavior, and negative reinforcement “involves the removal or avoidance of some ‘aversive’ (literally ‘painful’) state of affairs” such as an electric shock (Gross, 2020, p. 177).


6 Real-Life Examples of the Theory

Examples of conditioningWhile more acceptable at the time, much of the research into classical conditioning would now be questionable or unethical.

Several such studies provide interesting and insightful findings and are regularly discussed within the literature on the classical conditioning theory, but we do not suggest that they are appropriate or ethical.


Early examples of classical conditioning research

  • Experimental neurosis: Taking discrimination training one stage further, Pavlov (1927) trained dogs to salivate when a circle was presented, but not an ellipse (Gross, 2020).

In subsequent tests, he presented the dogs with a series of shapes that morphed from an ellipse until almost becoming circular. He found that dogs began to act neurotic, trembling, whining, and defecating.

It appears that the dogs did not know how to react, facing an increasingly difficult balance between generalization and discrimination.

  • Little Albert: When nine months old, Little Albert, as he was named in the 1920 study, was tested in an ethically dubious research study regarding his responses to the following stimuli (Watson & Rayner, 1920):
    • White rat
    • Rabbit
    • Dog
    • Monkey
    • Masks (with and without hair)
    • Cotton wool
    • Burning newspapers
    • A hammer striking a steel bar behind his head

Only the last four stimuli scared Albert and were labeled UCS. The others, having no response, were considered neutral or CS. Fear was designated as the UCR.

When Albert was 11 months old, the rat (neutral or CS) and the hammer sound (UCS) were presented simultaneously seven times.

Because of the new pairing, the previously neutral rat now produced fear in the unfortunate Albert.

The deliberately produced phobia also extended to other stimuli, including the rabbit, the dog, and even cotton wool. And while over time, the effect reduced, it was still present to a small degree a month later (Gross, 2020).

  • Little Peter: For no apparent reason, a two-year-old known as Little Peter exhibited an extreme phobia of animals including rabbits, rats, and frogs; cotton wool; fur coats; and feathers (Jones, 1924).

However, when Peter ate his lunch, a wire cage containing a rabbit was placed in front of him and brought closer to where he sat each day.

After 40 sessions and a series of 17 steps, he could ultimately eat his lunch while stroking the rabbit or have it running free in the room with him.

The study provides a possible early research example of systematic desensitization (Gross, 2020).


3 Examples in the classroom

Teachers can apply the lessons learned from classical conditioning in the classroom (Cherry, 2019; Shrestha, 2017):

  • Positive educational environments: A positive and supportive environment can reduce students’ anxiety and fear.

When paired with more challenging activities such as presenting in front of the class, a supportive environment can cause valuable and helpful associations that lead to increased confidence (Cherry, 2019).

  • Bullying: When a child experiences bullying in the class or on the playground, they may form associations that lead to fear and dread at the very mention or thought of school. It may continue throughout education.

  • Recognition of performance: Drawing attention to student performance in class can have a positive or negative association. A child who is ridiculed or embarrassed because of poor test results may begin to fear failure.

Such feelings could also lead to a positive outcome such as motivation for extra studying.


Classical Conditioning vs Operant Conditioning

While both classical conditioning and operant conditioning are vital concepts in behavioral psychology, they are quite different learning processes (Gross, 2020).

Under classical conditioning, Pavlov showed the importance of involuntary, automatic behaviors. A previously neutral stimulus, such as a bell, can be paired with an unconditioned stimulus, such as food, that automatically produces an unconditioned response (salivating).

Once the dog is trained, the bell creates the unconditioned response.

On the other hand, operant conditioning uses either reinforcement or punishment to increase or decrease behavior, respectively (Skinner, 1957).

Rewarding hard work in class regardless of the results can lead to extra effort and recognition that tests are an opportunity to validate understanding.

Similarly, when students are punished for talking in class, the problematic behavior decreases. Operant conditioning, therefore, strengthens or weakens behavior (Skinner, 1957; Gross, 2020).


9 Strengths & Weaknesses of Pavlov’s Theory

Pavlov's TheoryThe following strengths and weaknesses apply to the classical conditioning theory and behaviorism as a whole (Kompa, 2020).



  • Results can be reliably reproduced.
  • The theory explains automatic responses, though not the influence of other factors such as personality and genetic factors.
  • The theory is highly relevant for animal conditioning (less so for humans, as the theory ignores an individual’s choice or agency).


  • Classical conditioning and behaviorism do not consider human agency including conscious self-awareness, intentionality, etc.
  • The theory ignores innate and inherited factors.
  • It does not explain how people make procedural decisions, such as choosing between more than one option or goal and how to overcome an obstacle.
  • It does not explain individual differences or variations in learning.
  • There is a host of ethical concerns regarding testing behavioral modifications.
  • Animal studies may not represent human response and behavior.

While both a strength and a weakness, depending on your motives and ethical stance, “people can use classical conditioning to exploit others for their gain” (Rehman et al., 2020).


Resources From PositivePsychology.com

We have many resources that therapists can use with their clients to gain additional insight into their behavior and regain control when it is damaging or unhelpful.

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  • Behavioral Experiments to Test Beliefs Worksheet
    Use this worksheet to test automatic negative thoughts and reevaluate associated beliefs and assumptions.


A Take-Home Message

Discovering classical conditioning was a fortunate accident. After all, Pavlov was a physiologist researching digestion in dogs (Rehman et al., 2020).

And yet his discovery, sometimes referred to as Pavlov conditioning, significantly affected behaviorism and the broader field of psychology.

He recognized that by repeatedly pairing a neutral stimulus (bell) with an unconditioned stimulus (food), he was ultimately able to trigger a conditioned response (salivating).

By varying the pairing of the neutral (conditioned) stimulus and the unconditioned stimulus, he could even affect the size of the reaction (conditioned response). And when the conditioned stimulus continued in the absence of the unconditioned stimulus, the conditioned response ultimately disappeared.

Behaviorism assumes that all learning results from interactions with the environment, and therefore, that the environment shapes our behavior. As a theory, it contrasts with modern psychological theory, which recognizes the importance of innate and inherited factors and human agency (Buss, 2016).

Classical conditioning undoubtedly has its limitations, but it had a significant effect on psychology in the first half of the 20th century and provided a valuable lens to look at animal and (to a restricted degree) human behavior.

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  • Buss, D. M. (2016). Evolutionary psychology: The new science of the mind. Routledge.
  • Cherry, K. (2019, September 5). How classical conditioning works: An overview with examples. Verywell Mind. Retrieved April 28, 2021, from https://www.verywellmind.com/classical-conditioning-2794859
  • Gross, R. D. (2020). Psychology: The science of mind and behaviour. Hodder and Stoughton.
  • Jones, M. C. (1924). The elimination of children’s fears. Journal of Experimental Psychology, 7, 382–390.
  • Kompa, J. S. (2020). Strengths and limitations of behaviorism for human learning [Web log]. Retrieved April 28, 2021, from https://joanakompa.com/2015/05/02/strengths-and-limitations-of-behaviorism-for-learning/
  • Pavlov, I. P. (1927). Conditioned reflexes. Oxford University Press.
  • Rehman, I., Mahabadi, N., Sanvictores, T., & Rehman, C. (2020). Classical conditioning. StatPearls. Retrieved April 27, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK470326/
  • Shrestha, P. (2017, November 17). Classical conditioning examples. Psychestudy. Retrieved April 28, 2021, from https://www.psychestudy.com/behavioral/learning-memory/classical-conditioning/classical-examples
  • Skinner, B. F. (1957). Verbal behavior. Century-Crofts.
  • Watson, J. B., & Rayner, R. (1920). Conditioned emotional reactions. Journal of Experimental Psychology, 3, 1–14

About the Author

Jeremy Sutton, Ph.D., is a writer and researcher studying the human capacity to push physical and mental limits. His work always remains true to the science beneath, his real-world background in technology, his role as a husband and parent, and his passion as an ultra-marathoner.

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