Comparison of Pattern Discrimination with Traditional External-s Discrimination in the Rat 1

Abstract

12 rats were trained in a runway on a single alternating partial reward schedule and 12 others on an irregular partial reward schedule. Six rats within each schedule were provided with auditory stimuli paired with R or N trials. Reliable discriminations developed in both groups receiving external stimuli as well as the group receiving the alternating schedule but no auditory stimuli (pattern discrimination group). The alternating schedule produced better discrimination in each comparison suggesting that aftereffects (or other intertrial events) are at least equal and perhaps superior to external stimuli as discriminanda for rats. The results of an extinction phase showed superior persistence for Ss trained without external stimuli.