A consideration of extinction procedureof avoidance response

Abstract

This study was based on Miller and Mowrer's hypothesis that avoidance responding is motivated by anxiety. According to this hypothesis, it may be concluded that the avoidance response without the termination of CS is more quickly extinguished than the response with the termination of CS. The purpose of this experiment was to test the above.Forty albino rats were divided into four groups.The apparatus was a slightly modified Miller-Mowrer shuttle box. The left side of the box which was divided into two equal chambers was a starting box and the other was a goal box. The CS was a light bulb. The US was a 0.4 mA electric shock which was given through a grid.For the conditioning of experimental group I and II, the starting box had a grid floor and its walls were white, but the floor and walls of the goal box were covered with a sheet of black paper.As soon as the subject was put into the starting box. CS was started and then US was given four second later. When the subject ran into the goal box. CS and US were terminated. This trial was repeated until the subject met the necessary criterion of five successive avoidance responses.They were then immediately given the extinction procedure. In experimental group I, only the US was omitted. In experimental group II, US was not only omitted but the goal box was changed to be identical to the starting box, that is, the CS was not terminated by the response. Fifty extinction trials were given on the first day followed by twenty trials per day until the criterion of three successive non-responding within sixty second was obtained.Table I and II show mainly the number of trials retained to meet the extinction criterion. As the results of examination, control group I verified that the conditioning of experimental groups ware not pseudo-conditioning.