Effects of the mere presence of conspecifics on the motor performance of rats: Higher speed and lower accuracy.

Many studies on humans and animals have shown that the mere presence of another individual or individuals accelerates the motor performance speed of the subject individual. However, it has not been well investigated whether the mere presence of another individual affects the accuracy of motor performance in animals. In this study, we developed a novel task (run-and-pull task) to simultaneously investigate both the speed and accuracy of motor performance in rats and examined the effect of the mere presence of another rat on the task performance of the subject rat. Rats were first trained in isolation to run a runway and then pull a lever on the terminal end of the runway. After training, the subject rats were required to perform the task in isolation (Single) or in front of a non-competitive confederate rat without direct interaction (Pair). The results showed that the latency to start running and to pull the lever were shorter and the accuracy of the lever-pull movement was lower in the Pair condition than in the Single condition. These findings suggest that the mere presence of another individual increased the speed and decreased the accuracy of the motor performance of rats.