The Horizontal–Vertical Curvature Illusion in Touch Is Present in Three-Dimensional Objects and Raised Lines (original) (raw)

The horizontal-vertical curvature illusion, prevalent in both vision and touch, leads to the overestimation of vertical extents compared to horizontal ones. This study investigates whether utilizing three-dimensional (3-D) objects and free exploration methods can reduce or eliminate this illusion, revealing that it remains strong even in the presence of such stimuli. Results indicate that the illusion is influenced by the configuration and mode of exploration, with particular emphasis on the role of radial and tangential motions in the perception of these dimensions.