Abstract
Predictability effects upon chronic learned helplessness. 25 albine rats were exposed to 9 sessions of uncontrollable shocks. Predictability was manipulated. Animals were randomly assigned to one of five groups that received uncontrollable shocks with: a) a previous signal (CE-UN), b) a posterior signal (UN-CE), c) a previous and a posterior signal (CE-UN-CE), without signal (UN), or d) without uncontrollable shock (Cont.). In a subsequent controllable test, results indicated that the longer safety period group (CE-UN) showed low conditioned fear (immovilization); pretreatment-postreatment weight differences were not significant in this group. However, all uncontrollable shock groups showed performance deficits (latency time). Results are discussed in terms of conditioned fear, predictability, feedback hypothesis and pavlovian cues.
