STIMULUS CONTROL OF PAVLOVIAN FACILITATION

Two experiments were conducted using an autoshaping procedure with pigeons to examine whether dimensional stimulus control by a Pavlovian facilitator parallels the control established following operant discrimination training. Facilitation training consisted of the presentation of a black vertical line on a white background as the B stimulus in a feature‐positive discrimination in which the A stimulus (white keylight) was followed by grain presentation only if preceded by B. In this way, B facilitates or sets the occasion for pecking at A. Subsequent testing for generalization along the line‐orientation dimension produced decremental gradients when the facilitation paradigm incorporated an explicit feature‐negative stimulus (B‐). These results parallel the decremental control obtained following operant discrimination training and suggest that Pavlovian facilitators and instrumental discriminative stimuli are functionally equivalent. 1991 Society for the Experimental Analysis of Behavior