The causal role of vision in the development of spatial coordinates: Evidence from visually impaired children

Many findings suggest that visual deprivation in early life negatively affects the development of spatial competence and that sighted and visually impaired individuals use different strategies to encode spatial positions. This study aims to assess the role of vision in developing spatial coordinates by running three studies in a sample of children and adolescents with and without visual impairments (n = 42, 16 female, 8-18 years old, 100% European), using visual and auditory versions of Simon task with uncrossed and crossed hands posture. The first study assessed that visual and auditory external coordinates mature in parallel in sighted children. The second showed that if vision is available but degraded, it is sufficient to calibrate spatial performance in the auditory system, even if the visual performance remains impaired. The third experiment showed that the total lack of visual experience results in an impaired spatial performance also in the other spared modalities. Our results suggest that vision impairments have different consequences on developing spatial competence. They also highlighted the necessity of early assessment and interventions in visually impaired children that take into account different residual abilities.