RESPONSE STRENGTH IN OPEN AND CLOSED ECONOMIES

Response strength was measured in open and closed economies using tests of resistance to change. In Experiment 1, responses were reinforced under fixed ratio schedules of reinforcement that ranged from 40 to 240. Rats in the open economy responded during a 45-min session and were immediately fed supplemental food in their home cage. Rats in the closed economy received all of their food by responding in an extended session. At each fixed ratio value, responding was disrupted by response-independent food and extinction, and response strength was indexed by the degree of response suppression relative to baseline. Response rate in the closed economy was higher than in the open economy, but no consistent difference in response strength was found. Experiment 2 was a replication of Experiment 1 using two open economy groups. One group was maintained at 80% free-feeding body weight for the entire experiment, and the other group was maintained at 90% under fixed ratio 40, 85% under fixed ratio 80, 75% under fixed ratio 160, and 70% under fixed ratio 240. Response suppression from free food and extinction was the same for both groups, suggesting that increased food deprivation under larger fixed ratios observed in Experiment 1 did not contribute to the results of that experiment. The data suggest that the ability to respond at relatively high rates under very large fixed ratio schedules of reinforcement in a closed economy does not reflect greater response strength as measured by the resistance-to-change paradigm. © 1990.