AVOIDANCE CONDITIONING AND ADRENOCORTICAL FUNCTION IN RAT

Six male rats were trained on an unsignaled (Sidman-type) avoidance schedule, on which each response postponed the next shock, and no warning signal was present. Measurement of plasma corticosteroid levels, during both the resting state and after exposure to ether stress, was made prior to training and at regular intervals during the course of several months of avoidance conditioning. It was found that animals exhibiting higher pre-training stress responses attained greater avoidance performance proficiency. Moreover, after individual differences in avoidance performance developed, greater proficiency was found to be accompanied by higher resting steroid levels. These data suggest that there may be a strong interrelation between the behavioral and endocrinological responses to stress of the kind present in aversive learning contingencies. © 1969.