CONTEXT SPECIFICITY OF CONDITIONED-REINFORCEMENT EFFECTS ON DISCRIMINATION ACQUISITION

Pigeons were trained on a series of reversals of a simultaneous form d iscrimination in which the trial outcomes were separated from the choi ce responses by an 8-s delay interval. Different conditions were defin ed by the stimuli occurring during the two halves of the delay interva l. Discrimination learning was greatly facilitated by having different ial stimuli during the delay following correct versus incorrect choice s. When the differential stimuli appeared only at the midpoint of the delay, some facilitation occurred relative to when no different stimul i occurred, but there was substantially less facilitation than when th e differential stimuli occurred immediately contingent an choice. A re versed-stimulus condition, in which the stimulus at the onset of the d elay following a correct choice was the same as that during the last s egment of the delay following an incorrect choice, and the stimulus at the onset of the delay following an incorrect choice was the same as that preceding food during the last segment of the delay following a c orrect choice, also facilitated discrimination learning relative to th e nondifferential stimulus conditions.