CONTEXTUAL CONTROL OF PAVLOVIAN FEATURE-POSITIVE AND FEATURE-NEGATIVE DISCRIMINATIONS

Three pigeons were trained with a Pavlovian serial feature-positive (F-P) discrimination task in a light context, in which the houselight was on, and with a Pavlovian serial feature-negative (F-N) discrimination task in a dark context, in which the houselight was off. Three other pigeons were trained with the F-P task in the dark context and the F-N task in the light context. These two contextual conditions were changed randomly trial by trial. The farmer birds learned the tasks within 60 sessions, by responding exclusively to the target keylight after the feature tone in the light context and by responding exclusively to the target not preceded by the feature in the dark context. Two of the latter birds required separate training of the F-P and the F-N tasks to acquire the discrimination: responding exclusively to the target after the feature in the dark context and responding exclusively to the target not preceded by the feature in the light context. The third bird, however, failed to learn the discrimination even with separate training. These results indicate that the four-term contingency (the context-feature target-food relationship) controlled the birds' behavior in the Pavlovian setting. The insertion of a temporal gap between the feature and the target impaired the F-N discrimination, although it had little effect on the F-P discrimination.