Remote haptic perception of slanted surfaces shows the same scale expansion as visual perception.

Previous work has shown that overestimates of geographic slant depend on the modality used (verbal or haptic). Recently, that line of reasoning has come into question for many reasons, not the least of which is that the typical method used for measuring "action" has been the use of a palm board, which is not well calibrated to any type of action toward slanted surfaces. In the present work, we investigated how a remote haptic task that has been well calibrated to action in previous work is related to verbal overestimates of slanted surfaces that are out of reach. The results show that haptic estimates are perceptually equivalent to the verbal overestimates that have been found in numerous previous studies. This work shows that the haptic perceptual system is scaled in the same way as the visual perceptual system for estimating the orientation of slanted surfaces that are out of reach.