The role of visual experience in knowledge of spatial layout

Adventitiously blinded, congenitally blind, and sighted adults made relative distance judgments in a familiar environment under three sets of instructions—neutral with respect to the metric of comparison, euclidean (straight-line distance between landmarks), and functional (walking distance between landmarks). Analysis of error scores and multidimensional scaling procedures indicated that, although there were no significant differences among groups under functional instructions, all three groups differed from one another under euclidean instructions. Specifically, the sighted group performed best and the congenitally blind group worst, with the adventitiously blind group in between. The results are discussed in the context of the role of visual experience in spatial representation and the application of these methods for evaluating orientation and mobility training for the blind.