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Classical Conditioning

Classical Conditioning

By Dr. Saul McLeod, updated 2021

Classical conditioning (also known as Pavlovian or respondent conditioning) is learning through association and was discovered by Pavlov, a Russian physiologist. In simple terms, two stimuli are linked together to produce a new learned response in a person or animal.

The most famous example of classical conditioning was Pavlov's experiment with dogs, who salivated in response to a bell tone. Pavlov showed that when a bell was sounded each time the dog was fed, the dog learned to associate the sound with the presentation of the food.

John Watson proposed that the process of classical conditioning (based on Pavlov’s observations) was able to explain all aspects of human psychology.

Everything from speech to emotional responses was simply patterns of stimulus and response. Watson denied completely the existence of the mind or consciousness. Watson believed that all individual differences in behavior were due to different experiences of learning. He famously said:

"Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select - doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations and the race of his ancestors” (Watson, 1924, p. 104).

Classical Conditioning Examples

There are three stages of classical conditioning. At each stage the stimuli and responses are given special scientific terms:

Stage 1: Before Conditioning:

In this stage, the unconditioned stimulus (UCS) produces an unconditioned response (UCR) in an organism.

In basic terms, this means that a stimulus in the environment has produced a behavior / response which is unlearned (i.e., unconditioned) and therefore is a natural response which has not been taught. In this respect, no new behavior has been learned yet.

For example, a stomach virus (UCS) would produce a response of nausea (UCR). In another example, a perfume (UCS) could create a response of happiness or desire (UCR).

This stage also involves another stimulus which has no effect on a person and is called the neutral stimulus (NS). The NS could be a person, object, place, etc.

The neutral stimulus in classical conditioning does not produce a response until it is paired with the unconditioned stimulus.

Stage 2: During Conditioning:

During this stage, a stimulus which produces no response (i.e., neutral) is associated with the unconditioned stimulus at which point it now becomes known as the conditioned stimulus (CS).

For example, a stomach virus (UCS) might be associated with eating a certain food such as chocolate (CS). Also, perfume (UCS) might be associated with a specific person (CS).

For classical conditioning to be effective, the conditioned stimulus should occur before the unconditioned stimulus, rather than after it, or during the same time. Thus, the conditioned stimulus acts as a type of signal or cue for the unconditioned stimulus.

Often during this stage, the UCS must be associated with the CS on a number of occasions, or trials, for learning to take place. However, one trail learning can happen on certain occasions when it is not necessary for an association to be strengthened over time (such as being sick after food poisoning or drinking too much alcohol).

Stage 3: After Conditioning:

Now the conditioned stimulus (CS) has been associated with the unconditioned stimulus (UCS) to create a new conditioned response (CR).

For example, a person (CS) who has been associated with nice perfume (UCS) is now found attractive (CR). Also, chocolate (CS) which was eaten before a person was sick with a virus (UCS) now produces a response of nausea (CR).

Little Albert Experiment

Watson & Rayner (1920) were the first psychologists to apply the principles of classical conditioning to human behaviour by looking at how this learning process may explain the development of phobias.

They did this in what is now considered to be one of the most ethically dubious experiments ever conducted – the case of Little Albert. Albert B.’s mother was a wet nurse in a children’s hospital. Albert was described as ‘healthy from birth’ and ‘on the whole stolid and unemotional’.

When he was about nine months old, his reactions to various stimuli (including a white rat, burning newspapers and a hammer striking a four-foot steel bar just behind his head) were tested.

Little Albert Classical Conditioning

Only the last of these frightened him, so this was designated the unconditioned stimulus (UCS) and fear the unconditioned response (UCR). The other stimuli were neutral because they did not produce fear.

When Albert was just over eleven months old, the rat and the UCS were presented together: as Albert reached out to stroke the animal, Watson struck the bar behind his head.

This occurred seven times in total over the next seven weeks. By this time the rat, the conditioned stimulus (CS), on its own frightened Albert, and fear was now a conditioned response (CR).

The CR transferred spontaneously to the rabbit, the dog and other stimuli that had been previously neutral. Five days after conditioning, the CR produced by the rat persisted. After ten days it was ‘much less marked’, but it was still evident a month later

Classical Conditioning in the Classroom

The implications of classical conditioning in the classroom are less important than those of operant conditioning, but there is a still need for teachers to try to make sure that students associate positive emotional experiences with learning.

If a student associates negative emotional experiences with school, then this can obviously have bad results, such as creating a school phobia.

For example, if a student is bullied at school they may learn to associate the school with fear. It could also explain why some students show a particular dislike of certain subjects that continue throughout their academic career. This could happen if a student is humiliated or punished in class by a teacher.

Critical Evaluation

Classical conditioning emphasizes the importance of learning from the environment, and supports nurture over nature. However, it is limiting to describe behavior solely in terms of either nature or nurture, and attempts to do this underestimate the complexity of human behavior. It is more likely that behavior is due to an interaction between nature (biology) and nurture (environment).

The process of classical conditioning can probably account for aspects of certain other mental disorders. For example, in post-traumatic stress disorder (PTSD) sufferers tend to show classically conditioned responses to stimuli present at the time of the traumatising event (Charney et al., 1993). But since not everyone exposed to the traumatic event develops PTSD, other factors must be involved, such as individual differences in people’s appraisal of events as stressors and the recovery environment, such as family and support groups.

There have been many laboratory demonstrations of human participants acquiring behaviour through the process of classical conditioning. It is relatively easy to classically condition and extinguish conditioned responses, such as the eye-blink and galvanic skin responses.

However, applying classical conditioning to our understanding of complex human behaviour such as memory, thinking, reasoning or problem-solving has proved more problematic.

In normal adults the conditioning process can apparently be overridden by instructions: simply telling participants that the unconditioned stimulus will not occur causes an instant loss of the conditioned response, which would otherwise extinguish only slowly (Davey, 1983).

Most participants in an experiment are aware of the experimenter’s contingencies (the relationship between stimuli and responses) and in the absence of such awareness often fail to show evidence of conditioning (Brewer, 1974).

There are also important differences between very young children or those with severe learning difficulties and older children and adults regarding their behaviour in a variety of operant conditioning and discrimination learning experiments.

These seem largely attributable to language development (Dugdale & Lowe, 1990). This suggests that people have rather more efficient, language-based forms of learning at their disposal than just the laborious formation of associations between a conditioned stimulus and unconditioned stimulus.

Even behaviour therapy, one of the apparently more successful applications of conditioning principles to human behaviour, has given way to cognitive– behaviour therapy (Mackintosh, 1995).

A strength of classical conditioning theory is that it is scientific. This is because it's based on empirical evidence carried out by controlled experiments. For example, Pavlov (1902) showed how classical conditioning could be used to make a dog salivate to the sound of a bell.

Supporters of a reductionist approach say that it is scientific. Breaking complicated behaviors down to small parts means that they can be scientifically tested. However, some would argue that the reductionist view lacks validity. Thus, while reductionism is useful, it can lead to incomplete explanations.

A final criticism of classical conditioning theory is that it is deterministic. This means that it does not allow for any degree of free will in the individual. Accordingly, a person has no control over the reactions they have learned from classical conditioning, such as a phobia.

The deterministic approach also has important implications for psychology as a science. Scientists are interested in discovering laws which can then be used to predict events. However, by creating general laws of behavior, deterministic psychology underestimates the uniqueness of human beings and their freedom to choose their own destiny.

Key Terminology

Neutral Stimulus
In classical conditioning, a neutral stimulus (NS) is a stimulus that nitially does not evoke a response until it is paired with the unconditioned stimulus. For example, in Pavlov’s experiment the bell was the neutral stimulus, and only produced a response when it was paired with food.

Unconditioned Stimulus
In classical conditioning, the unconditioned stimulus is a feature of the environment that causes a natural and automatic unconditioned response. In pavlov's study the unconditioned stimulus was food.

Unconditioned Response

In classical conditioning, an unconditioned response is an unlearned response that occurs automatically when the unconditioned stimulus is presented. Pavlov showed the existence of the unconditioned response by presenting a dog with a bowl of food and the measuring its salivary secretions

Conditioned Stimulus
In classical conditioning, the conditioned stimulus (CS) is a substitute stimulus that triggers the same response in an organism as an unconditioned stimulus. Simply put, a conditioned stimulus makes an organism react to something because it is associated with something else. For example, Pavlov’s dog learned to salivate at the sound of a bell.

Conditioned Response
In classical conditioning, the conditioned response (CR) is the learned response to the previously neutral stimulus. In Ivan Pavlov's experiments in classical conditioning, the dog's salivation was the conditioned response to the sound of a bell.
In the initial period of learning, acquisition describes when an organism learns to connect a neutral stimulus and an unconditioned stimulus.
In psychology, extinction refers to gradual weakening of a conditioned response by breaking the association between the conditioned and the unconditioned stimuli.

For example, when the bell was repeatedly rang and no food presented Pavlov’s dog gradually stopped salivating at the sound of the bell.

Spontaneous Recovery
Spontaneous Recovery is a is a phenomenon of Pavlovian conditioning that refers to the return of a conditioned response (in a weaker form) after a period of time following extinction. For example, when Pavlov waited a few days after extinguishing the conditioned response, and then rang the bell once more, the dog salivated again.

In psychology, generalisation is the tendency to respond in the same way to stimuli that are similar but not identical to the conditioned stimulus. For example, in Pavlov's experiment, if a dog is conditioned to salivated to the sound of a bell, it may later salivate to a higher pitched bell.

In classical conditioning, discrimination is a process through which individuals learn to differentiate among similar stimuli and respond appropriately to each one.

For example, eventually Pavlov’s dog learns the difference between the sound of the 2 bells and no longer salivates at the sound of the non-food bell.

How to reference this article:

McLeod, S. A. (2018, August 21). Classical conditioning. Simply Psychology.

APA Style References

Bremner, J. D., Southwick, S. M., Johnson, D. R., Yehuda, R., & Charney, D. S. (1993). Childhood physical abuse and combat-related posttraumatic stress disorder in Vietnam veterans. The American journal of psychiatry.

Brewer, W. F. (1974). There is no convincing evidence for operant or classical conditioning in adult humans.

Davey, B. (1983). Think aloud: Modeling the cognitive processes of reading comprehension. Journal of reading, 27(1), 44-47.

Dugdale, N., & Lowe, C. F. (1990). Naming and stimulus equivalence.

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

Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20, 158–177.

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

Watson, J. B. (1924). Behaviorism. New York: People's Institute Publishing Company.

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

How to reference this article:

McLeod, S. A. (2018, August 21). Classical conditioning. Simply Psychology.

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