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To our knowledge, no study has examined the effect of mere presence on accuracy of performance in animals. Therefore, we developed an experimental task to measure rats' motor performance (speed and accuracy) in a social condition. Rats were trained to run on a runway and pull down a lever at the end of the runway. In testing, rats performed the task solitarily (single) or in the presence of a confederate rat beyond the lever (pair or a social condition). As indices of the performance speed, we measured the time needed to start running, run through the runway, and pull down the lever. As the index of performance accuracy, we counted the number of trials in which rats could pull down the lever during their first attempt. One-way and two-way repeated-measure analyses of variance were used to analyze the data. This run-and-pull task enabled us to examine the effect of the presence of another conspecific on both speed and accuracy of motor performance in one experiment. The results showed that rats performed the task faster but less accurately in pair sessions than in single sessions. This protocol would be a valid animal model to examine the effect of mere presence on speed and accuracy of motor performance in rats.

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., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)