RVESC · The Role of Visual Experience in Spatial Cognition

The Role of Visual Experience in Spatial Cognition

This project originally involved the investigation of the role of visual experience (i.e. experience with visual input) in the development of spatial cognition; in particular, it wanted to better assess whether visual experience determines the type of spatial information used to remember the position of objects arranged in a room-sized environment. Aside finding results corroborating this hypothesis on the role of visual experience, the original project was expanded by investigating how visual experience affects semantic memory, spatial representation of numbers, and brain organisation. More in detail, the results showed that, in order to 'store' spatial information, people without visual experience (i.e. congenitally blind individuals) used an entirely different type of spatial information than participants with visual experience (i.e. 'late' blind and blindfolded sighted participants). Nevertheless, the overall performance across the three groups did not differ. In other words, visual experience determines a preference for a given type of spatial information (i.e. 'egocentric' spatial information for congenitally blind people) to store spatial knowledge. Aside its theoretical relevance, this finding is important for the training techniques directed to the visually impaired population, because it suggests that training should be 'tailored' for the spatial preferences of a given blind group. Additionally, we found that, when asked to remember semantically related material (i.e. lists of related words) congenitally blind participants were able to report more words and were less prone to 'false memories' (i.e. reporting words related to those of the list but not present on the list) than participants with visual experience. This suggests that the absence of visual input triggers the 'recruitment' of the ex-visual areas for carrying out semantic tasks. In other words, the strong performance of congenitally blind participants may be supported by 'extra neural' capacity. These results suggest also that congenitally blind individuals may be more reliable auditory witnesses. Another project, investigated whether visual experience affects the spatial representation of numbers; several studies reported that numbers are spatially represented along a 'number-line' extending from-left-to-right. The result of a this study employing blind and sighted participants showed that the lack of visual experience affects the spatial representation of numbers, which are egocentrically organised starting from the right hand side - all our participants were right-handed. This result supports neuro-imaging studies reporting that spatial and numerical representations share the same cortical area in the parietal lobe. A sub-area of the parietal lobe is known for mapping tactile locations of the face (namely, the VIP area). The idea of this study was to investigate whether this tactile map of the face is genetically pre-disposed or whether it is visually driven. Therefore, an fMRI study was carried out to investigate this issue. It was used an apparatus delivering tactile stimulation on the face under the form of 'air-puffs'. In-progress results, suggest that congenitally blind participants did not show the tactile map of the face in the VIP area, while late blind individuals showed 'regular' maps. In sum, starting from spatial cognition, it was investigated the role of visual experience in other domains as far as semantic memory, and the results always suggested that the experience with visual input plays a crucial role.

Data: CORDIS, © European Union