The role of geographical slant in virtual environment navigation

We investigated the role of geographical slant in simple navigation and spatial memory tasks, using an outdoor virtual environment. The whole environment could be slanted by an angle of 4degrees. Subjects could interact with the virtual environment by pedaling with force-feedback on a bicycle simulator (translation) or by hitting buttons (discrete rotations in 60degrees steps). After memory acquisition, spatial knowledge was accessed by three tasks: (i) pointing from various positions to the learned goals; (ii) choosing the more elevated of two landmarks from memory; (iii) drawing a sketch map of the environment. The number of navigation errors (wrong motion decisions with respect to the goal) was significantly reduced in the slanted conditions. Furthermore, we found that subjects were able to point to currently invisible targets in virtual environments. Adding a geographical slant improves this performance. We conclude that geographical slant plays a role either in the construction of a spatial memory, or in its readout, or in both.