Doing the opposite to what another person is doing.

The three studies presented here aim to contribute to a better understanding of the role of the coordinate system of a person's body and of the environment in spatial organization underlying the recognition and production of gestures. The paper introduces a new approach by investigating what people consider to be opposite gestures in addition to identical gestures. It also suggests a new point of view setting the issue in the framework of egocentric versus allocentric spatial encoding as compared to the anatomical versus non-anatomical matching which is usually adopted in the literature. The results showed that the role of the allocentric system as a key player was much more evident when participants were asked to "do the opposite" as compared to when they imitated which indicates that the two tasks really are different from each other. Response times were also quicker when people "did the opposite" indicating that this is an immediate response and not the result of "reversing an imitation". These findings suggest that the issue of how the oppositional structure of space impacts on human perception and the performance of gestures has probably been underestimated in an area of research which traditionally focuses exclusively on imitation.