Gestural and Verbal Evidence of Conceptual Representation Differences in Blind and Sighted Individuals

This preregistered study examined whether visual experience influences conceptual representations by examining both gestural expression and feature listing. Gestures-mostly driven by analog mappings of visuospatial and motoric experiences onto the body-offer a unique window into conceptual representations and provide complementary information not offered by language-based features, which have been the focus of previous work. Thirty congenitally or early blind and 30 sighted Turkish speakers produced silent gestures and features for concepts from semantic categories that differentially rely on experience in visual (non-manipulable objects and animals) and motor (manipulable objects) information. Blind individuals were less likely than sighted individuals to produce gestures for non-manipulable objects and animals, but not for manipulable objects. Overall, the tendency to use a particular gesture strategy for specific semantic categories was similar across groups. However, blind participants relied less on drawing and personification strategies depicting visuospatial aspects of concepts than sighted participants. Feature-listing revealed that blind participants share considerable conceptual knowledge with sighted participants, but their understanding differs in fine-grained details, particularly for animals. Thus, while concepts appear broadly similar in blind and sighted individuals, this study reveals nuanced differences, too, highlighting the intricate role of visual experience in conceptual representations.