Haptic Compensation in Blind People's Conceptual Representations.

Vision is typically dominant in our perception of the world. Such asymmetry is also observed in conceptual representations. This could be driven by perceptual experience or learned from other input, such as language. In this study we tested the role of direct perceptual experience in conceptual representation by investigating the sensory underpinnings of word meanings in blind and sighted individuals. Seventeen early-blind and 17 matched sighted Dutch native speakers rated 100 Dutch nouns for their sensory associations across six modalities (vision, audition, haptic, interoception, gustation, and olfaction) on a 0 (not at all) to 5 (very much) scale. To cover a range of concepts we used five semantic categories thought to be strongly associated with different sensory modalities: animals (vision), instruments (audition), tactile objects (haptics), food (gustation), and odor objects (olfaction). We found no difference between blind and sighted individuals in their ratings of visual associations, suggesting that conceptual associations with vision can be learned indirectly via means beyond direct visual perception. However, blind participants did associate concepts more strongly with haptics than sighted participants for all semantic categories except animals. This is evidence for crossmodal compensation in conceptual representation, in line with enhanced tactile acuity reported elsewhere for blind individuals. Overall, the results point to a role for perceptual experience in conceptual representation, but suggest there are other strategies that can be recruited to learn about perception, supporting hybrid models of semantic representation.