Some Asymmetrical Drive Summation Phenomena

Abstract

There have been a number of studies of the effect of an irrelevant thirst drive upon the performance of hungry rats (Kendler, 1945; Siegel, 1946; Kendler & Law, 1950; Danziger, 1953; Levine, 1956). In each case it was reported that a high irrelevant thirst is detrimental to food-relevant performance. (The thirst is said to be irrelevant because no water was present in the experimental situation.) In the Kendler and Law and the Levine studies, comparable decrements were found in the water-relevant performance of animals under high irrelevant hunger. In all of these studies the high irrelevant drive condition was 22 hr. (except that Danziger used 17 hr.); only Kendler (1945 ) varied the intensity of the irrelevant drive in a systematic way between 0 and 22 hr. Kendler found chat the resistance to extinction of the bar-press response was an inverted U-shaped function of the intensity of the irrelevant thirst drive. As the hours of irrelevant drive increased from zero there was first a facilitation of the performance, and then at a high level of irrelevant drive a decrement in performance was found. Kendler interpreted the facilitory phase as evidence for Hull's drive summation hypothesis and the decrement phase as indicating that for the high irrelevant drive case some adjustment was required in that hypothesis (Hull, 1943, p. 245). Subsequent Es, perhaps because generally they have found decrements in performance, have tended to emphasize the possibility of interference or inhibition factors. The present study reports an investigation of drive summation phenomena under a broader range of irrelevant drive conditions than has been used before. METHOD