Stimulus Function in Errorless Simultaneous Discrimination

Abstract

Pigeons trained to perform a simultaneous visual discrimination with few or no errors by a procedure in which the negative stimulus (S—) was gradually introduced, preferred a neutral (novel) stimulus (S°) to the S—used in the original training. Ss receiving more abrupt presentation of S— and who made more errors, chose randomly between S— and S°. These data suggest that S— may be inhibitory or aversive following errorless learning.