Release from Habituation

One useful discrimination learning technique is called release from habituation. Habituation is the gradual cessation (stopping) of a response when the same stimulus is repeated many times. Habituation happens reliably in a variety of situations (it is "a robust phenomenon" as scientists say). If there is a loud ticking in the room, soon you will not hear it. If you live near traffic, soon you "tune it out." If you repeat a tone, soon a baby will ignore it. But if a different sound is played, the baby may show a startle response. If that happens, then obviously the baby can tell the difference between the new tone and the earlier tones. This phenomenon, called release from habituation is an indicator of discrimination. It shows that an organism reacts differently to two categories of stimuli.

What is "release from habituation"? What are some discrimination abilities in babies?

Experiments using release from habituation have shown remarkable discrimination abilities in babies. For example, babies have a primitive sense of number. A baby can be shown a series of slides in which there are always three objects in various different positions (different objects each time). Soon the baby gets bored and stops responding to the pictures. But if a picture with four objects appears, the baby perks up and pays attention to it. Similar studies have shown that babies have the ability to distinguish between language sounds used in all different human languages before the age of one, but after the age of one their discrimination of some of these sounds disappears. Soon they discriminate only between language sounds they hear in their environments.

How did Pavlov produce an "experimental neurosis"?

Pavlov believed that being pressured to make excessively fine discriminations could trigger neurosis or mental disturbance. In one experiment, Pavlov taught a dog to discriminate between a circle and an oval. The location of the circle and the oval was changed randomly, so the dog had to discriminate between them on the basis of shape, not location. When the dog pointed its nose at a circle, it received food. When it pointed at the oval shape, it received an electric shock. Gradually Pavlov made the oval rounder and rounder. Soon it was hard to tell the oval from the circle. The dog began showing signs of distress, whining and defecating. Pavlov said this showed an experimental neurosis.

How did old-time Soviet psychologists use this concept to explain crazy Americans?

As mentioned earlier, the Soviet Union endorsed Pavlov's psychology, making it in effect the officially approved version of psychology in the country during the Communist era. I heard a Soviet psychologist who was visiting the U.S. use Pavlov's ideas about neurosis to explain the (to him) strange behavior of hippies in the mid-1960s. Observing longhaired young men tossing Frisbees on the University of Michigan campus during the late 1960s, the psychologist said—with a confident gleam in his eye—that he knew what caused this odd behavior. "It is your supermarkets. You have 20 different brands of soap, and who can tell which is best? The result is neurosis." In other words, he believed that the presence of many similar stimuli, requiring finer and finer discriminations, caused American youth to be mentally disturbed.


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