The effect of differential overtraining of the positive and negative stimulus on the aversiveness of the negative stimulus

Abstract

Six discrimination-sophisticated monkeys were trained on 18 problems, each of which contained intermixed trials on two discriminations. In six problems, the ratio of trials of the two discriminations was 4 to 1. Following training, a single test trial was given, which consisted of choice between the more trained (MT) and less trained (LT) negative stimuli. No consistent preference for either stimulus was demonstrated. In the remaining problems, either the negative or positive stimulus of one discrimination was overtrained. In the former condition, on test trials, the LT negative stimuli were preferred, while in the latter, the MT negative stimuli were preferred. These results could be accounted for by the relative frequency during training of nonrewarded responses to the MT and LT negative stimuli.