Abstract
To perform a movement in a sophisticated and flexible manner, inputs from different sensory modalities needs to be gathered inside and outside the body. Such multisensory integration has been shown to occur in the peripersonal space, which immediately surrounds the body. Recent studies have reported improved visual processing in the peripersonal space. It was also shown that the peripersonal space can be extended when an agent uses a tool to explore the environment. Less is known, however, whether motor capability or tool-use affects visual representations of space distant from the body. Thus, the present study investigated the effect of extended motor capability on visual analysis in the extrapersonal space. Using a keyboard, participants manipulated a ball on the screen at a distance they could not reach by the hand. Their contrast threshold was measured before and after the manipulation task. As results, a group of participants who were able to control the ball showed improved visual sensitivity relative to those who passively watched the ball moving (Experiment 1). Furthermore, when participants could move the ball in a certain area of the screen but not in the other, improved visual sensitivity was observed only in the area where motor capability was experienced (Experiment 2A). The beneficial effect of motor capability, however, was not significant in the peripersonal space (Experiment 2B). Overall, the present study demonstrates that visual analysis of distant space can be improved by motor capability temporarily induced by tool-use. It further suggests that the sense of agency affects the representation of the extrapersonal space even without a physical connection between the body and the space.
Meeting abstract presented at VSS 2012