The effects of rapid versus controlled actions on perceptual hand maps

Perceiving the location of body parts in external space using position sense requires that proprioceptive signals coming from the body be combined with stored information about the size and shape of body parts. A widely used paradigm to investigate this metric representation of the body involves having participants judge the location of different landmarks on the hand. By comparing the relative location of different landmarks, perceptual maps of the hand can be constructed and compared to actual hand structure. These maps show large distortions that are highly stereotyped, and consistent across people. In this study, we investigated whether judgements in this paradigm are modulated by whether pointing responses are made in a controlled manner versus rapidly. In the controlled condition, participants were asked to make localisation judgements in a precise and deliberate way. In the rapid condition, in contrast, they were asked to make judgements quickly and intuitively. Highly similar distortions were apparent in both conditions. These results provide further evidence that the distortions of perceptual hand maps are not strongly dependent on the manner of response.