Effect of Unsignaled Delay of Reinforcement on Operant Conditioning in Pigeons

Abstract

Study objective:To investigate effects of an unsignaled delay in reinforcement on operant responses, after controlling reinforcement rates and inter-reinforcement intervals (IRIs). Design: Tandem VI x sec Fl y sec FT t sec schedule was used. This design enables control of reinforcement rates and inter-reinforcement intervals across conditions through adjusting x, y, and t. Setting: One-key operant boxes; hemp seeds were used as reinforcers. Subjects: 5 pigeons. Independent variables: In the tandem schedules, 6 values of reinforcement delay (t = 0, 0.5, 1, 2, 4, and 10 sec), and 2 values of the fixed component (y+t = 10 and 35 sec). The total of x+y+t was always 60 sec. Measures: Response rate, running rate, observed delay, and post-reinforcement pauses (PRPs). Results: (a) Reinforcement rates decreased as a negatively accelerated function of reinforcement delay, (b) Post-reinforcement pauses increased as reinforcement delays increased. (c) Post-reinforcement pauses and running rates tended to correspond to inter-reinforcement intervals even with reinforcement delay. Conclusion: Reinforcement rates decrease as a negatively accelerated function of reinforcement delay even when reinforcement rate and inter-reinforcement interval are controlled. Some suggestions are made regarding dynamic processes in reinforcement delay.