Post-Shock Discriminations in the Acquisition of Free-Operant Avoidance By Rats

Abstract

Acquisition of free-operant avoidance was studied during 5 days of training in 36 rats. The response-shock interval was 20 sec, and an escape response was required in shock. Temporal discriminations of the response-shock interval were indicated by rising conditional probability of response functions for some of the animals on Days 4 and 5 of training. No Ss showed temporal discriminations in their over-all interresponse time distributions before Day 4. However, as early as the first day of training, discriminations were obtained with some Ss when responding directly after shock was considered separately. These early post-shock discriminations appeared only for Ss that eventually became efficient avoiders. However, many Ss learned to avoid without showing a temporal discrimination.