The effects of postweaning rearing conditions on the response to stressful tasks in the rat

Abstract

The effects of individual- and group-housing conditions were examined in three experiments. In Experiment 1, individually housed rats were more susceptible to sudden death by drowning than were group-housed rats, and daily handling increased this susceptibility. In Experiment 2, the test was one typically used in “learned helplessness” experiments, escape from shock. Individually housed animals took longer to escape from shock than did animals housed in groups. In Experiment 3, individually housed and group-housed rats were handled and given either no further treatment or electroconvulsive shock (ECS) or a change in housing conditions before being tested for escape from shock. Animals individually housed throughout were slower to escape shock than were each of the other five groups. These findings suggest that there are both behavioral and physiological similarities between the operations of individual housing and exposure to inescapable shock. Explanations in terms of learned helplessness and noradrenergic depletion are discussed. © 1980, Psychonomic Society, Inc.. All rights reserved.