A Behavioral Adaptation Approach to Identifying Visual Dependence of Haptic Perception

Both haptic and visual senses play a role in how we explore our environment. Previous studies have shown that vision plays a very strong role in perception of object stiffness, yet quantification of the contributions of both haptic and visual feedback remains elusive. This study uses a behavioral adaptation approach in order to better understand how humans perceive stiffness. Namely, subjects make targeted reaches across a virtual surface of varying stiffness, adapting to the new environment. The hand´s cursor position is visually distorted to seem more stiff for one group, less stiff for another, and no distortion for the control group. Area reaching deviation (ARD) and post-adaptation interface forces, used in previous studies, were the two outcome measures used to determine differences between groups. We compare the slopes of the post-adaptation force-stiffness relations to quantify the effect of visual distortion. Our results indicate that making a stiff surface look more compliant has a greater effect on humans than making a compliant surface look more stiff