Grouping of places to regions does influence human route planning

It is widely accepted that spatial memory is hierarchically structured. However, little is known about the consequences of hierarchical organization on route-planning and navigation. Here we demonstrate the influence of grouping places into regions on active navigation in virtual environments. Subjects had to learn a spatial layout of 12 interconnected places which could be grouped into three regions according to the object types found at each place. In subsequent navigation tasks subjects were asked to find the shortest routes connecting 3 of those places. When there were two alternative solutions of equal length, subjects preferred the route that led through fewer regions. We conclude that regions exist within spatial memory and that route-planning is based on region, not place connectivity