We are interested in behavioral "plasticity" of individuals who have been deprived of vision from birth. More specifically, we have studied the manner in which the individual mentally represents the space around them, and the way in which the inidividual benefits from information coming from other senses. The aim of the study consists in understanding if the essential stages for the construction of the mental representations are in operation from an early age, and up to what point behavioral/cerebral plasticity could mitigate this early visual deprivation. Three series of experiments were proposed with participants who were categorized as blind from birth, late blind, sighted and blindfolded, or sighted with eyes open. The first two experiments consisted of a task of mental exploration and of mental comparison of distances. In these two experiments, the participants learned the configuration of a small spatial environment through verbal description or tactile exploration. The third series of experiments was aimed at examining whether the immersion of the individual in the environment would improve their performance. We designed an immersive Virtual Reality system for "3D sound", which allows for the generation of a human scale environment consisting of a spatial distribution of virtual sound sources in which the individual has the capacity to move about. The results suggest that the size of the initial configuration does not have an effect on the treatment of the spatial relations, even though blind from birth participants made more erros with regards to distance evaluation with the smaller sized configuration.
