Visuospatial experience shapes the form of gestures: Blind speakers gesture with more precise spatial tracking of motion than sighted speakers.

Co-speech gestures emerge from the interaction between visuospatial experience and speech formulation, but what happens when visual experience is absent from birth? Blind individuals gesture in ways consistent with their native language, albeit they gesture less frequently. However, nothing is known about whether their gesture form differs from that of sighted individuals. Using computer vision technologies, this study examines whether gesture kinematics are shaped by visuospatial experience. In an auditory motion-description task, we analyzed spontaneous path-only gestures - depicting motion trajectories - produced by 20 congenitally blind, 21 blindfolded, and 21 sighted Turkish speakers. We assessed the gestures' alignment with actual motion paths, along with duration and size. Blind participants produced gestures that were more precisely aligned with the motion trajectories, as well as larger and longer. These findings show that altered spatial cognition in blindness enhances gesture precision. The study underscores the role of sensorimotor experience in shaping gesture form.