Visual and Tactile Sensory Systems Share Common Features in Object Recognition.

Although we use our visual and tactile sensory systems interchangeably for object recognition on a daily basis, little is known about the mechanism underlying this ability. This study examined how 3D shape features of objects form two congruent and interchangeable visual and tactile perceptual spaces in healthy male and female participants. Since active exploration plays an important role in shape processing, a virtual reality environment was used to visually explore 3D objects called digital embryos without using the tactile sense. In addition, during the tactile procedure, blindfolded participants actively palpated a 3D-printed version of the same objects with both hands. We first demonstrated that the visual and tactile perceptual spaces were highly similar. We then extracted a series of 3D shape features to investigate how visual and tactile exploration can lead to the correct identification of the relationships between objects. The results indicate that both modalities share the same shape features to form highly similar veridical spaces. This finding suggests that visual and tactile systems might apply similar cognitive processes to sensory inputs that enable humans to rely merely on one modality in the absence of another to recognize surrounding objects.Significance StatementHuman brains are able to precisely and rapidly identify tactile and visual objects, an ability indicating that we use visual and tactile information interchangeably to recognize surrounding objects. This study examined the role of shape features that enable human reliance on visual or tactile sensory modalities for object recognition and provides evidence that the visual and tactile modalities not only generate two highly congruent perceptual spaces but also use the same shape features to recognize a novel object. This finding contributes to explaining why visual and tactile senses are interchangeable.