Abstract
The layout of an environment must be learned from experience with particular routes. One possibility is that the process of path integration links environmental locations into a metric “cognitive map,” which would enable novel shortcuts. We have demonstrated that humans are unable to use path integration alone to perform novel shortcuts. Instead they rely on local landmarks over metric knowledge (whether they appear at the beginning, middle, or end of a novel path; Psychonomics, 2002). These previous studies were performed in open environments with small clusters of visible landmarks, which may have increased subject's dependence on landmarks. Therefore we now pursue this question for complex multi-leg routes in a closed, structured environment with restricted views, a virtual hedge maze (Harrison et al., VSS 2001). Participants walked in an immersive virtual environment (12 m × 12 m) while wearing a head mounted display (60 × 40 deg, 50 ms latency). The hedge maze contained eleven places (statue, bird bath, etc.). During training, participants learned the layout of places with a free exploration period, followed by structured practice along specific routes. During testing, the hedges were removed, and subjects were asked to walk the overland shortcuts between learned places. We compare equidistant shortcuts that are linked by more or less circuitous routes. If spatial knowledge is truly metric, then performance should be equal. Implications for theories of human metric navigation will be discussed.