Naturalistic Visuomotor Behaviours Reveal Reduced Handedness Lateralization In Autism

Abstract

Autistic individuals often exhibit differences in perceptual and visuomotor functioning, potentially reflecting reduced cortical specialization. The current study investigates how handedness, a robust marker of cerebral lateralization, is modulated in autistic and non-autistic right-handed adults (n=27 per group) using a naturalistic LEGO® model-building task. Participants recreated five models from blocks placed on a standardized tabletop, enabling detailed analysis of real-world visuomotor behaviour. Autistic participants showed a lower proportion of right-hand grasps and more balanced cross-body reaches, indicating reduced lateralization. They also preferred blocks closer to their hands, suggesting larger safety margins in 3D space use. Movement trajectory analyses revealed more idiosyncratic action sequences and slower completion times compared to non-autistic participants, reflecting reduced motor efficiency. These findings demonstrate reduced specialization of hand use in autism, which may contribute to challenges and differences in visuomotor control.