HOW TO TEACH A PIGEON TO MAXIMIZE OVERALL REINFORCEMENT RATE

In two experiments deviations from matching earned higher overall rein forcement rates than did matching. In Experiment 1 response proportion s were calculated over a 360-response moving average, updated with eac h response. Response proportions that differed from the nominal reinfo rcement proportions, by a criterion that was gradually increased, were eligible for reinforcement. Response proportions that did not differ from matching were not eligible for reinforcement. When the deviation requirement was relatively small, the contingency proved to be effecti ve. However, there was a limit as to how far response proportions coul d be pushed from matching. Consequently, when the deviation requiremen t was large, overall reinforcement rate decreased and pecking was even tually extinguished. In Experiment 2 a discriminative stimulus was add ed to the procedure. The houselight was correlated with the relationsh ip between response proportions and the nominal (programmed) reinforce ment proportions. When the difference between response and reinforceme nt proportions met the deviation requirement, the light was white and responses were eligible for reinforcement. When the difference between response and reinforcement proportions failed to exceed the deviation requirement, the light was blue and responses were not eligible for r einforcement. With the addition of the light, it proved to be possible to shape deviations from matching without any apparent limit. Thus, i n Experiment 2 overall reinforcement rate predicted choice proportions and relative reinforcement rate did not. In contrast, in previous exp eriments on the relationship between matching and overall reinforcemen t maximization, relative reinforcement rate was usually the better pre dictor of responding. The results show that whether overall or relativ e reinforcement rate better predicts choice proportions may in part be determined by stimulus conditions.