The effect of prior random reinforcement on brightness discrimination learning in rats

Abstract

An experiment is described in which rats were transferred from an insoluble, random reinforcement problem to a brightness discrimination. A second group was given position training under 50% contingent reinforcement before the transfer task. Both treatments produced strong position stereotypes which continued during the transfer task, but learning was significantly slower for subjects which had experienced the insoluble problem. The effect occurred whether or not the brightness cues were present during the initial training, although their presence significantly impaired subsequent learning under both conditions. The results are interpreted in accordance with the hypothesis of learned irrelevance.