Stimulus generalization in Psychology

The concept of Stimulus Generalization is found both in classical as well as operant conditioning. Stimulus generalization basically evokes a similar response by a conditioned stimulus, after a response has been conditioned. For example, if a child has been conditioned to fear a rat, it will show signs of fear to all or any objects that resembles the conditioned stimulus which is a rat, such as a white toy rat.

In other words, stimulus generalization is the tendency of a subject to respond to a stimulus or a group of stimuli similar but not identical to the original CS. Let us consider another example, a subject may initially make the desired response when exposed to any sound rather than making such a response only to a specific sound. Such generalization can occur in both classical and operant conditioning, that too in a condition when a conditioned stimulus is used. But here is a good news, a subject can be trained to discriminate among sounds and to respond only to a specific sound.

In a popular Little Albert experiment, in which the researchers John B. Watson and Rosalie Rayner conditioned a little boy to fear a white rat. The researchers observed that the boy experienced stimulus generalization by showing fear in response to similar stimuli including a dog, a rabbit, a fur coat, a white Santa Claus beard and even Watson’s own hair.

Stimulus Generalization and Discrimination

Like mentioned earlier, the stimulus generalization can occur in both classical conditioning and operant conditioning. Yet a subject can be taught to discriminate between similar stimuli and to only respond to a specific stimulus.  For example, suppose there is a dog that has been conditioned to run to his master as soon as he blows the whistle. Now there is every chance that this dog responds to all sounds of whistles that might not particularly be coming from his master. So he might respond to a variety of sounds that are similar to the sound of a whistle blown by his master. Thus, the trainer works with the dog and trains him to discriminate among different kinds of sounds and respond to his sound of whistle when blown.

There was yet another popular experiment conducted in 1921 in which the researcher Shenger, paired the taste of meat with sight of a circle. This meat be the unconditioned stimulus.  So every time the dog saw the circle, it elicited an unconditioned response in the form of salivation. But when the dog was shown an eclipse, the researcher observed that the dog still salivated, because eclipse was a little similar to the circle shown before. But after failing to pair the sight of the ellipse with the taste of meat, the dogs were able to eventually discriminate between the circle and ellipse. This was achieved when he didn’t receive the meat every time the eclipse was shown, the unconditional response slowly faded away. But the meat was presented with every sight of a circle, so this way the dog could discriminate between an eclipse and a circle and only responded in the form of salivation when the circle was shown.

Stimulus Generalization and Classical Conditioning

[large]One of the most common classically conditioned responses experienced by humans is Fear. Let us illustrate the fear of snakes to know how the phenomena of this stimulus generalization works in classical conditioning. Let us take an example of a 4 year-old child, who watches a few meters long Python snake on National geographic attacking and swallowing a little innocent looking mouse. Although this is a natural experience of a snake devouring a mouse. But because this child has a pet mouse of his own immediately imagines the snake coming to his room and attacking the pet mouse, at that very instance fears starts to pour in to the child who develops fear of snakes. Suppose, he spots a similar looking but harmless snake in his backyard while playing, on the sight of this snake, which is not exactly like the snake he saw on television, the same fear and adrenaline rush kicks in and he retreats. This is called Stimulus generalization.

Because this child has associated the characteristics of snake ( long, skinny, rapid tongue protrusions, eyes, flat nose, slithery body) with fear, it is not necessary that he would experience fear on the sight of snake particularly, but anything that has similar characteristics would elicit this behavior of fear in him.