The interactions between haptics and vision in active shape perception

The sense of touch, or rather haptic perception, can be considered an inherently active sense: In order to explore an object through the sense of touch we need to make physical contact and very often move our hands to create the relevant touch sensations and form a haptic understanding of the object. In their now “classical” study, Lederman and Klatzky investigated the role of such active hand movements in perceiving different object properties, and they identified several different exploration modes that we tend to use (Lederman & Klatzky, 1987, Cognitive Psychology). In recent work, we have dived a bit deeper into two specific explorations modes for shape perception: static touch and dynamic exploration. We have found that each of these modes adapts to object shape individually and furthermore cannot be mixed when combining redundant estimates from vision and touch. That is, when combining redundant information across the senses for determining global object shape, the perceptual system gets the most benefit when the separate senses also use the same or very similar exploration modes. This research has illuminated a key role for proprioception in both haptic perception of object shape as well as for combining visual and haptic information.