The Mental Maps of the Blind: The Role of Previous Visual Experience

The structure of spatial representation in congenitally and adventitiously blind 11-year-old children was examined by means of pointing, map-drawing, and spatial reasoning on two simple routes over repeated trials. Although all the children learned how to travel each route successfully after only one trial, three out of four of the congenitally blind children showed a complete lack of spatial understanding, as evinced by “egocentric” or “self-referent” spatial coding strategies, whereas all the adventitiously blind subjects exhibited appropriate externally referent spatial strategies compatible with convential two-dimensional maps. The role of previous visual experience in the encoding and decoding of spatial material in memory is discussed.