Visual experience and the haptic horizontal-vertical illusion

An experiment was conducted with blind individuals to examine the effect of visual experlence on the horizontal-vertical illusion In touch. Groups of early blind, late blind, and low vision subjects examined tangible raised-line drawings of L and Inverted T figures. A tangible sliding ruler was used for size estimates. The results showed that the horizontal-vertical illusion was not dependent upon visual experience or visual imagery, since similar illusory overestimation of the verticals occurred with early blind, late blind and low vision subjects