Wider IPD Makes People Perceive Their Body to be not so Large when Large Hands are Presented

Abstract

It is known that hand size and the interpupillary distance (IPD), as well as eye height from the ground, are some of the determinants of body size. We investigated the effect of simultaneous changes in hand size and IPD on size perception regarding the body and the external world in virtual reality. We manipulated the hand size and the IPD (normal hand and normal IPD, large hand and normal IPD, large hand and large IPD) while vertically increasing the participants' eye height. Our main results indicated that a wider IPD combined with larger hands made participants perceive their body to be smaller than when the IPD was normal. Thus, the IPD influences the perception of body size when large hands are presented. This is a novel result because it suggests the probability of an interaction effect between the IPD and the hand size, or between the IPD and the presence of hands, on body size perception.