In 1879 Ivan Pavlov, the Russian physiologist and pioneer of classical conditioning, began his research work on the digestive process, primary that of dogs. The focal point of his investigation was the salivation reflex in dogs. It was already known that dogs would salivate if food powder were led into their mouths, as it was a reflex. ‘The dogs would salivate every time the food powder was presented. Pavlov observed that after some time, the dogs at times salivated just before food was put into their mouths. They also salivated at the slight of the food, and even at the slight of the lab assistant who brought food for them. This is where the concept of classical conditioning emerged.

Pavlov`s standard procedure involved a quiet, distract free laboratory, which gave the experimenter full control over events experienced by a lightly restrained dog. From time to time the dog was given access to food; and each presentation was accompanied (usually slightly preceded) by the occurrence of a neutral event, such as a flashing light. After several training trials (pairings of light and food), the dog would salivate at the flash of light, before any food had appeared. Salivation at the presentation of food is called an unconditioned response (UR), since it occurs automatically (unconditional). The food is an unconditioned stimulus (Us). The animal’s tendency to salivate when the light flashes is conditional on the light having been paired with food, so this is referred to as a conditioned response (CR) and the event that evokes it as a conditioned stimulus (CS).the whole training procedure was labeled conditioning. As other forms of training, introduced later, have also been described as conditioning, Pavlov`s version became known as classical conditioning.

The importance of classical conditioning

If classical conditioning were simply a procedure that allows a reflex response previously solely by a particular US (such as food) to come under the control of another stimulus (such as the presentation of a light), then perhaps there would be no reason to regard it as fundamentally important to our understanding of learning. But three features of our analysis give us reason to believe that is fundamentally important:

It is fundamental to learning about the relationship among environment events. Sensory preconditioning tells us that when neutral stimulus co-occurs, an association forms between them. Simply moving through the environment will expose the human/ animal to sequences of events that go together, and the associations that form among them will constitute an important piece of knowledge.

1)   Acquisition: the stage when the stimulus in question generates a conditioned response; this is the stage of initial learning when responses are established and then gradually strengthened as a result of repeated pairing and presentation. 

2)   Extinction: the unlearning of the conditioned response by weakening it, leading to its disappearance; for example using the same principles as those for learning the response. The state when the conditioned stimulus i.e. boll, buzzer. Gong e.t.c does not accompany the unconditioned stimulus e.g. food. The response gradually diminishes, extinguishes, or declines, as the UCS repeatedly does not appear with the CS. 

3)   Spontaneous Recovery: does the response disappear permanently, once extinction, the dog salivated again on hearing the bell/ buzzer. Consider the case of someone who left but the very sight of someone else who is smoking makes him feel like smoking. The same may happen with a child whose fear than they initially were; similar to their extinction takes place sooner and easily.

4)   Generalization: stimulus similar to the original CS may happen elicit same response as to the CS or UCS e.g. a buzzer responded to as a bell. Pavlovian experiments showed that the dogs also salivated on the tones that were similar to the original ones. Consider the case of Albert`s fear of all white – furry objects.

5)   Discrimination: the process whereby the organism learns to restrict its response to one specific stimulus; differentiating between similar stimuli. Pavlov`s dogs salivated only at the tones, which were similar in nature. Consider the case of a child who is scared of the neighbor`s dog alone (that barks every time the child passes by), and not all dogs.

6)   Higher order conditioning: a process when a already conditioned stimulus is repeatedly paired with a neutral stimulus, and ultimately the neutral stimulus begins to evoke the same response as to the original stimulus. Consider the case of a child who was scared of the neighbor`s dog, became scared of all dogs, and finally started screaming at the mere name of a dog.

Applications of classical conditioning in everyday life

Negative emotional response: fears, phobias fear of reptiles, dark

places and school phobia.

Positive emotional response: feelings of relaxation, and happiness….thinking of going on a holiday.

Advertising: associating model with the product.

Psychotherapy; systematic desensitization, aversive therapy.

Conditioned Drug response: vomiting inducing drugs were repeatedly paired with the sound of a tone; eventually the mere sound of that name of cough syrup, or who faint at the name of a clinic. Smoking, coffee, and tea people who are additicted to caffeine and nicotine start feeling relaxed and stimulated even before the intake. 

Over eating: most obese people start feeling hungry at the sight of a restaurant or at the smell of food.