Discrimination and Extinction as a Function of Internal and External Discriminanda

Abstract

32 rats were trained on a successive discrimination problem for 40 days. 4 separate groups received the factorial combinations of presence vs absence of internal (aftereffects) or external (alley color) discriminanda. Discrimination learning was quite apparent in the rats with external cues but failed to develop in the rats trained only with internal cues. During an extinction phase the rats trained with only internal cues proved to be more persistent. These results were related to an earlier experiment suggesting the superiority of internal cues.