Object Size Perception in Immersive Virtual Reality: Avatar Realism Affects the Way We Perceive

How does the representation of an embodied avatar influence the way in which a human perceives the scale of a virtual environment? It has been shown that the scale of the external environment is perceived relative to the size of one's body. However, the influence of avatar realism on the perceived scale has not been investigated, despite the fact that it is common to embody avatars of various representations, from iconic to realistic. This study examined how avatar realism would affect perceived graspable object sizes as the size of the avatar hand changes. In the experiment, we manipulated the realism (high, medium, and low) and size (veridical and enlarged) of the avatar hand, and measured the perceived size of a cube. The results showed that the size of the cube was perceived to be smaller when the avatar hand was enlarged for all degrees of realism of the hand. However, the enlargement of the avatar hand had a greater influence on the perceived cube size for the highly realistic avatar than for the medium-level and low-level realism conditions. This study shed new light on the importance of the avatar representation in a three-dimensional user interface field, in how it can affect the manner in which we perceive the scale of a virtual environment.