Saturday, March 3, 2012

Operant Conditioning

Operant Conditioning : Learned Helplessness
Operant Conditioning has been applied in a number of ways to human behaviour. One example is work by researcher Martin Seligman that has led to a theory of depression.

Experimental Helplessness
Seligman's work began with dogs in escape and avoidance conditioning procedures. He set up a chamber with a barrier in the center. Every few minutes a light came on for 10 seconds, followed by a painful electric shock. The dog could escape the shock by jumping over the barrier; the dog could avoid the shock altogether by jumping over the barrier during the light presentation.

Dogs learned to escape fairly quickly, and most learned to avoid the shock with extensive practice. However, Seligman was disapointed with the slow avoidance learning. He tried a different procedure with some new dogs. These animals were first restrained in a harness and given several light-shock pairings. Seligman thought that this might teach them the significance of the light as a signal for shock, and that this might encourage fast avoidance learning in the chamber. To the contrary, these dogs performed poorly in the chamber. When the light was presented they acted afraid. Although unrestrained, the animals lay on the floor and whimpered when the shock was presented.

Depression As Learned Helplessness
After thinking about this result, Seligman realized that the training with light and shock in the harness had taught these animals that they could not do anything aobut the delivery of shock. He called this phenomenon learned helplessness. Seligman and colleagues have performed many additional studies, and learned helplessness has been demonstrated in cats, rats and humans.

According to Seligman, the key factor in the development of learned helplessness is the experience of having a lack of control over the environment. Further, he has theorized that several such experiences of lack of control, and the accompanying feeling of helplessness, is the cause of human depression. He has pointed out that losses of a spouse, relative or loved one are cases where one may perceive a lack of control. These situations lead to helpless feelings and depression.

This view of depression has implications for therapy with depressed clients. Seligman has proposed that depressed clients should be encouraged to engage in activities that will lead to success and a perceived sense of control over the environment.

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