Automatic spatial updating during locomotion without vision.

People can update their spatial relationships relative to the environment while walking without vision. The hypothesis that such updating is automatic was tested in a locomotor task in which the subjects were asked to refrain from updating their positions. Subjects walked without vision to one of four previously seen targets via a second location. In one condition--the updating condition--the subjects were asked to walk to the real position of the target relative to the second location; in another--the ignoring condition--they were asked to imagine that they had not moved from the starting point and to walk from the second location as if walking to the target from the initial location. When the subjects were asked to start walking to the target as soon as it was named by the experimenter, they performed better in the updating condition than in the ignoring condition. When the subjects were allowed more time to respond, the difference in performance between these two conditions disappeared. The results suggest that the subjects automatically updated their positions as they moved, but that, given enough time, they could override this updating retrospectively using more deliberate cognitive processing.