Social disruption of performance on a DRL schedule

Four rats were trained to stable performance on a schedule which reinforced only bar presses exceeding an inter-response time of ten sec. (DRL 10 sec). The trained animals, when performing in the presence of other animals, emitted responses having shorter inter-response times than when alone, and as a consequence received fewer reinforcements than when alone. These results are consistent with the theory that being in the presence of other organisms increases arousal, which in turn increases the probability that the dominant response will be emitted.