What is classical conditioning?

Classical conditioning is a type of learning that has a significant impact on the school of psychology (called behaviorism). Russian physiologist Ivan Pavlov discovered that classical conditioning is a learning process that occurs through the correlation between environmental stimuli and natural stimuli.

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The basics of classic conditioning

Although psychologists have not found classical conditioning at all, it has had a huge impact on the school of psychology called behaviorism.

Behaviorism is based on the following assumptions:

  • All learning happens through interaction with the environment
  • Environmental shaping behavior

Classical conditioning involves placing a neutral signal before the naturally occurring reflection. In Pavlov’s classic experiments on dogs, the neutral signal is a tone, and the naturally occurring reflection is a response to food. By linking neutral stimuli with environmental stimuli (food), tonal sounds can produce a salivation response.

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The working principle of classical conditioning

In order to learn more about the working principle of classical conditioning, it is very important to be familiar with the basic principles of the process. Classical conditioning involves forming a correlation between two stimuli, leading to a learned response.There are three basic stages in this process.

The first stage: before conditioning

The first part of the classical conditioning process requires a naturally occurring stimulus that will automatically trigger a response. Drooling in response to food odors is a good example of natural irritation.

At this stage of the process, unconditioned stimulus (UCS) leads to unconditioned response (UCR).For example, present food naturally (UCS) and automatically trigger the salivation response (UCR).

At this point, there is also a neutral stimulus, which will not have any effect-for now. Until this neutral stimulus is paired with UCS, it will not cause a response.

Let’s take a closer look at the two key components of this classic conditioning phase:

  • An unconditional stimulus is a stimulus that unconditionally, naturally and automatically triggers a response.For example, when you smell one of your favorite foods, you may immediately feel very hungry. In this example, the smell of the food is unconditionally irritating.
  • An unconditional response is an unlearned response that occurs naturally to an unconditional stimulus.In our example, hunger for food smells is an unconditional response.

In the preconditioned reflex phase, the unconditioned stimulus is paired with the unconditioned response. Then introduce a neutral stimulus.

Phase 2: Adjustment period

In the second stage of the classical conditioning process, the previous neutral stimulus is repeatedly paired with the unconditional stimulus. As a result of this pairing, an association is formed between the previous neutral stimulus and UCS.

At this time, the once-neutral stimulus is called conditioned stimulus (CS). The subject has now adapted to the response to this stimulus. A conditioned stimulus is a previous neutral stimulus that, after being associated with an unconditioned stimulus, will eventually trigger a conditioned response.

In our previous example, suppose that when you smell your favorite food, you also hear the whistle. Although the whistle has nothing to do with the smell of food, if the whistle is paired with the smell multiple times, the whistle will eventually trigger a conditioned response. In this case, the whistle is the conditioned stimulus.

The conditioning phase involves pairing neutral stimuli with unconditioned stimuli. Ultimately, the neutral stimulus becomes a conditioned stimulus.

Stage 3: After conditioning

Once a relationship is established between UCS and CS, even if there is no unconditioned stimulus, the presentation of the conditioned stimulus alone will cause a response. The resulting reaction is called Conditional Reaction (CR).

Conditional response is the learned response to previous neutral stimuli. In our example, when you hear the whistle, the conditioned response will feel hungry.

In the post-conditioned reflex phase, the conditioned stimulus alone triggers the conditioned response.

Key principle

Behaviorists describe many different phenomena related to classical conditioning. Some of these elements involve the initial establishment of the response, while others describe the disappearance of the response. These elements are important for understanding the classical conditioning process.

Let us take a closer look at the five key principles of classical conditioning.


Acquisition is the initial stage of learning, when the response is initially established and gradually strengthened.In the acquisition phase of classical conditioning, neutral stimuli and unconditional stimuli are repeatedly paired.

As you may remember, unconditional stimulation is something that triggers a response naturally and automatically without any learning. After the association is established, the subject will begin to issue a behavior in response to the previously neutral stimulus, which is now called a conditioned stimulus. It is at this point that we can say that we have received a response.

For example, suppose you are conditioning a dog to salivate when the bell rings. You repeatedly pair the presentation of the food with the sound of the bell. You can say that once the dog starts to react to the bell, it has already acquired this response.

Once the response is established, you can gradually increase the salivation response to ensure that the behavior is well learned.


Extinction refers to the reduction or disappearance of the occurrence of conditioned reactions. In classical conditioning, this happens when the conditioned stimulus is no longer paired with the unconditioned stimulus.

For example, if the smell of food (unconditioned stimulus) is paired with a whistle (conditioned stimulus), it will eventually cause a conditioned response to hunger.

However, if the unconditioned stimulus (the smell of food) is no longer paired with the conditioned stimulus (whistle), the final conditioned response (starvation) will disappear.

Spontaneous recovery

Sometimes, even after a period of extinction, the learned response suddenly reappears. Spontaneous recovery is the reappearance of a conditioned response after a rest period or a period of weakening of the response.

For example, imagine that after training a dog to saliva to a bell, you stop reinforce the behavior, and this response will eventually disappear. After a rest period without conditioned stimuli, you suddenly press the bell, and the animal will spontaneously resume the previously learned response.

If conditioned stimuli and unconditioned stimuli are no longer related, they will disappear soon after spontaneous recovery.

Stimulus generalization

Stimulus generalization is the tendency of a conditioned stimulus to cause a similar response after the response is adjusted.For example, if a dog has become accustomed to salivating when the bell rings, the animal may also show the same response to stimuli similar to conditioned stimuli.

For example, in John B. Watson’s famous Little Albert experiment, a child would be afraid of a white mouse. The child also showed fear of other fuzzy white objects (including plush toys and Watson’s own hair), thereby showing irritating generalizations.

Stimulate discrimination

Discrimination is the ability to distinguish conditioned stimuli from other stimuli that are not paired with unconditional stimuli.

For example, if the ringtone is a conditioned stimulus, discrimination will involve being able to distinguish between the ringtone and other similar sounds. Because the subjects were able to distinguish these stimuli, they would only respond when conditioned stimuli appeared.

Classical conditioning example

It would be helpful to see a few examples of how the classic conditioning process works in experimental and real-world environments.

Fear response

John B. Watson’s experiment with Little Albert is a perfect example of a fear response.The child had no fear of white mice at first, but after the mice were repeatedly paired, they made loud and terrible sounds. When the mice were present, the child would cry. The child’s fear also generalized to other fuzzy white objects.

Before conditioning, the white rat is a neutral stimulus. An unconditional stimulus is a loud jingle, and an unconditional response is a fear response caused by noise.

By repeatedly pairing the mouse with the unconditional stimulus, the white mouse (now a conditioned stimulus) begins to evoke a fear response (now a conditioned response).

This experiment illustrates how phobias are formed through classical conditioning. In many cases, a single pairing of a neutral stimulus (such as a dog) and a terrible experience (being bitten by a dog) can lead to a persistent phobia (fear of a dog).

Taste aversion

Another example of classical conditioning can be seen in the development of conditioned taste aversion. Researchers John Garcia and Bob Koelling first noticed this phenomenon when they observed how rats exposed to nausea-causing radiation developed aversion to flavored water after the radiation and water appeared together.

In this example, radiation represents an unconditional stimulus, and nausea represents an unconditional response. After the two are paired, the flavored water is a conditioned stimulus, while the nausea that forms when exposed to water alone is a conditioned response.

Later studies have shown that this classic conditioned aversion can be produced by a single pairing of conditioned and unconditioned stimuli.

Researchers also found that if the conditioned stimulus (the taste of food) occurs several hours before the unconditioned stimulus (the stimulus that causes nausea), this disgust can even occur.

Why does such an association develop so fast? Obviously, forming this association can bring survival benefits to organisms. If an animal eats something that makes it sick, it needs to avoid eating the same food in the future to avoid illness or even death.

This is a good example of so-called biological preparation. Some associations are easier to form because they help to survive.

In a famous field study, researchers injected sheep carcasses with a poison that makes coyotes sick but does not kill them. The goal is to help the shepherds reduce the number of sheep lost due to the hunting of coyotes.

The experiment not only worked by reducing the number of sheep killed, but also caused some coyotes to develop a strong aversion to sheep, so that they would actually run away due to the smell or sight of the sheep.

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In fact, people’s reaction is not like Pavlov’s dog. However, classical conditioning has many practical applications. For example, many dog ​​handlers use classic conditioning techniques to help people train their pets.

These techniques are also useful for helping people cope with phobias or anxiety problems. For example, the therapist may repeatedly combine anxiety-causing things with relaxation techniques to establish connections.

Teachers can help students overcome anxiety or fear by creating a positive classroom environment, thereby applying classical conditioning in the classroom. Combining anxious situations (such as performing in front of a group of people) with a pleasant environment helps students learn new associations. In these situations, the child will not feel anxious and nervous, but learn to stay relaxed and calm.