Cooperative responding in rats maintained by fixed- and variable-ratio schedules.

The present study investigated the effects of fixed-ratio (FR) and variable-ratio (VR) reinforcement schedules on patterns of cooperative responding in pairs of rats. Experiment 1 arranged FR 1, FR 10, and VR 10 schedules to establish cooperative responding (water delivery depended on the joint responding of two rats). Cooperative response rates and proportions were higher under intermittent schedules than under continuous reinforcement.