Abstract
The ability to represent one's orientation (i.e. heading) relative to a fixed reference frame is an essential component of spatial cognition. In a previous study (Marchette et al., 2014), we found that subjects use local environmental boundaries (i.e. walls) to anchor their sense of direction when they re-instantiate spatial views from a newly-learned environment. Here we investigate the role of egocentric experience in shaping this anchoring process. In three experiments, subjects learned virtual environments containing several target objects. On test trials, they re-instantiated views from the environment and reported the locations of target objects. To assess heading codes, we analyzed priming for repetition of imagined heading across successive trials. Exp. 1 tested whether egocentric experience could “break” geometric symmetry by training subjects in a symmetric (rectangular) room but beginning every learning trial with the subject facing the same direction. Priming was observed for views facing the same direction but not for views facing geometrically identical corners, indicating that the egocentric orientation during learning had an effect. In Exp. 2, geometry and egocentric experience were put into conflict using a “hairpin” maze consisting of rectangular corridors linked together to form a single path. Once again, egocentric experience broke the geometric symmetry: priming was obtained between views facing the same direction along the path of travel during learning but not between views facing the same absolute direction. Exp. 3 tested whether egocentric experience alone sufficed to anchor heading codes even in the absence of geometric boundaries by using an environment in which travel was constrained by "moats" rather than by walls. In this case, we observed no heading priming. Taken together, these results suggest that environmental boundaries are essential for anchoring one sense of direction, but that egocentric experience plays an important role in distinguishing between headings when geometry is ambiguous.
Meeting abstract presented at VSS 2015