Abstract
The layout of an environment must be learned from experience with particular routes. One possibility is that path integration serves to link environmental locations together into a metric “cognitive map,” which enables new short-cuts. However, Dyer (1991) found this was not the case in honeybees, who depend on salient visual landmarks to find a shortcut to a known location. We investigate (a) whether humans integrate learned routes into metric spatial knowledge, and (b) if so, whether this ability depends on proprioceptive or visual information for path integration. Participants were tested in a 40 × 40 ft virtual environment consisting of a field of colored posts that were only visible for a few meters, providing minimal local landmark information. They wore a head-mounted display (40 deg H × 60 deg V), and head position was measured with a hybrid sonic/inertial tracking system (50 ms latency). During training, they learned two legs of a triangle: the path from “home” to location A, the path from home to location B, and the angle between them. In the active condition, they walked these paths and angles (proprioception and vision); in the passive condition, they were moved through them in a wheelchair (vision); and in the blind condition, they were randomly rotated through the angle with eyes closed. During testing, participants tried to walk a short cut from A to B and from B to A. Errors in final position, path length, and path angle were measured. Results indicate large errors in short cut performance in the blind condition, compared with relatively accurate performance in the active condition. This suggests that people can derive reasonably good spatial knowledge from proprioceptive path integration, whereas highly local landmark information may not be sufficient to integrate across paths.
Supported by NSF LIS IRI-9720327.