Time allocation of responding or not-responding in a contingency degradation procedure

Abstract

Instrumental contingency is the conditional probability of a consequence given a response minus the probability of the same consequence given no response. This work replicated the effects of contingency degradation in rats. Two groups of rats with different reinforcement probabilities in four phases were used. In the first phase, two contingencies were scheduled; in the second phase, the contingency was the same and slightly positive for both groups but the reinforcement probabilities for responding and not responding were different; in the third phase the contingencies were reversed compared to the first phase; and finally in the last phase the contingency was the same, zero, for both groups however reinforcement probabilities for responding and not responding were different. The results replicate previous findings, but a detailed analysis suggests proportional time allocation of responding and not responding to the rate of reinforcement by each strategy. That is, variations in response rates would not be revealing the degree of control of the reinforcer over the behavior established by previous manipulations, but rather the time allocation to each strategy (responding or not) following obtained reinforcement rates.