Abstract
A navigator who becomes lost must identify her current location and recover her facing direction in order to restore her bearings. We tested the idea that these two tasks—place recognition and heading retrieval—might be mediated by distinct cognitive systems. Previous work has shown that both rodents and young children rely primarily on the geometric shape of navigable space to regain their sense of direction after disorientation, often ignoring non-geometric visual cues even when they are informative (Cheng, 1986; Hermer & Spelke, 1994). Notably, these experiments are almost always performed in single-chamber environments in which there is no ambiguity about place identity. We examined the navigational behavior of disoriented mice presented alternately with two rectangular chambers that were geometrically identical but distinguishable by horizontal or vertical stripes along one wall. Thus, the stripes could be used both to identify the chambers (place recognition) and also to disambiguate directions within the chambers (heading retrieval). In one chamber, mice were rewarded whenever they searched in the left corner nearest the striped wall, and in the other chamber, whenever they searched in the right corner nearest the striped wall. We found that in each chamber mice searched in the correct corner for that chamber or its geometrical equivalent (diagonally opposite) corner with equal frequency, and did so significantly more often than at the other corners. Thus, mice used the stripes to identify the chamber in which they were located, but not to disambiguate between the two geometrically-equivalent facing directions. These results suggest the existence of separate systems for place recognition and heading retrieval in mice that are differentially sensitive to geometric vs. non-geometric visual cues. We speculate that a similar cognitive architecture may underlie human navigational behavior.
Meeting abstract presented at VSS 2014