Spatial Updating 1 Allocentric and Egocentric Updating of Spatial Memories

Four experiments investigated spatial updating in a familiar environment. Participants learned locations of objects in a rectangular or a round room from a single stationary viewing position, walked to the center of the layout, and turned to appropriate facing directions before making pointing judgments. Locomotion was visually guided. Participants made judgments of relative direction (e.g., "Imagine you are standing at X and facing Y. Point to Z.") or egocentric pointing judgments (e.g., "You are facing Y. Point to Z."). The experiments factorially manipulated (a) the angular difference between the learning heading and the imagined heading and (b) the angular difference between the actual heading and the imagined heading. Pointing performance was best when the imagined heading was parallel to the learning view, even when participants were facing in other directions. Pointing performance was also better when the actual and the imagined headings were the same than when they were different. Room geometry did not affect these results. These findings indicated that spatial reference directions in memory were not updated during locomotion. Results are interpreted in terms of a new theory of human spatial memory and navigation.