Does blindness affect egocentric and allocentric frames of reference in small and large scale spaces?

Abstract

There is evidence that early deprivation of vision prompts the use of body-based, egocentric spatial representations in congenitally blind individuals, whereas previous visual experience favors the use of object-based, allocentric representations (e.g. Pasqualotto A, Spiller MJ, Jansari AS, Proulx MJ. Visual experience facilitates allocentric spatial representation. Behav Brain Res 2013;236:175–79). Here we investigated whether the influence of the visual status on the capacity to represent egocentric and allocentric spatial relations is mediated by the scale of space explored: large-scale (where a haptic+locomotor exploration is required) and small-scale space (where haptic exploration is needed). Our results showed that congenitally blind people had more difficulty in representing spatial information allocentrically with respect to late blind and sighted individuals, but this difficulty was stronger with large-scale than small-scale space. Instead, egocentric performance was better than the allocentric one for all groups, particularly in the small scale condition. These results suggest that visual experience is necessary to develop accurate allocentric representations especially of large-scale spaces. This is probably due to its capacity to convey a large amount of spatial information simultaneously and to its role on the setting up of multisensory brain areas underlying spatial cognition. In the absence of any kind of visual experience, egocentric spatial representations are favored, especially in small-scale space, when the body offers a stable anchor point.