DISCRIMINATIVE CONTROL BY THE SAMPLE STIMULUS AND RETENTION INTERVAL IN A DELAYED-RESPONSE TASK

Pigeons were trained on a three-key delayed discrimination task in whi ch one sample was followed by a 1-s delay and a response to the left k ey was reinforced. The other sample was followed by a 3-s delay and a response to the right key was reinforced. Upon acquisition subjects ex perienced a reversal of the reinforced choice responses, the delays, o r both reinforced responses and delays relative to samples. Subjects t hat experienced the dual reversal of reinforced choice responses and d elays acquired the reverse discrimination more rapidly than either gro up for which just one of these parameters had been reversed. In a seco nd experiment the same training procedure and reversals were used, how ever, a 2-s delay to reinforcement was added to 1-s retention delay tr ials. Results are discussed in terms of compound stimulus control by t he sample and the retention delay.