EFFECTS OF CONCURRENT SCHEDULES ON HUMAN FIXED‐INTERVAL PERFORMANCE 1

Abstract

Young adults performed a lever‐pressing task for money on two schedules of reinforcement: concurrent fixed‐interval 1 min—differential‐reinforcement‐of‐low‐rate 20‐sec, and concurrent fixed‐interval 1‐min—fixed ratio 100 responses. All subjects were trained on both schedules. Fixed‐interval performance concurrent with the differential reinforcement procedure was characterized by high constant rates with no post‐reinforcement pauses. Fixed‐interval performance concurrent with fixed ratio was characterized by low rates and lengthy post‐reinforcement pauses. These results differ from those obtained in prior studies on the effects of conditioning history upon subsequent fixed‐interval performance. The prior work, using non‐concurrent procedures, had shown that fixed‐interval performance following differential reinforcement of low rates was characterized by post‐reinforcement pauses and low rates, while fixed‐interval performance following fixed ratio exhibited high constant rates and no post‐reinforcement pause. The present results suggest that alternative concurrent contingencies are another major determinant of human fixed‐interval performance.