How Avatar Appearance Reshapes Internal Representation of Hand Geometry

Avatars whose appearance deviates from that of the physical body are widely used in virtual reality to enable experiences that go beyond biological limitations. To extend prior avatar research beyond subjective and performance-based measures, we systematically examined how variations in hand avatar appearance influence the internal representation of hand geometry. Using a structured set of 26 hand avatars, participants adapted to each avatar and subsequently reported their hand geometry. Results show that internal hand geometry does not change in direct correspondence with avatar geometry and exhibits a higher-dimensional structure than the avatar designs themselves. Furthermore, changes in hand geometry were organized along multiple interpretable dimensions rather than reflecting unsystematic variability. These findings suggest that avatar appearance is reinterpreted through internal bodily constraints. The proposed framework provides a basis for understanding avatar appearance in relation to body representation, supporting more informed avatar design beyond simple geometric mapping.