Social Control of Learned Avoidance and Some Evolutionary Implications
The effects of avoidance training and of social stimulation were studied in 42 rats assigned as littermates to one of 4 experimental groups or to a group of stimulus Ss. Avoidance-trained Ss received one brief escape conditioning experience in which reinforcement was initiated by Ss' exploratory behavior. Using time spent by Ss in different regions of the test chamber, it was possible to demonstrate effects of both factors, with a reduction of avoidance in the presence of a second animal. This phenomenon can be demonstrated in a test situation having common properties with natural environments. The social reduction of stress and of fear and avoidance which may accompany it is analyzed with respect to potential adaptive functions. It is proposed that this effect has been a major factor in the maintenance and further evolution of social cohesion in many species, including man.