Forgetting rate of topographical memory in a virtual environment

It is well admitted that spatial knowledge of large-scale environments is organized into route or survey representations (Thorndyke and Hayes-Roth 1982; Montello 1998; Allen 1999). The route representation consists in the memory trace of the sequence of landmarks encountered along a specific route and of the turns associated with each landmark. The survey representation is considered as being map-like, allowing direct access to the global layout of an environment. While extensive research has been devoted to the retention of verbal knowledge, very little is known about the retention of spatial knowledge. The available data show no systematic decline of performance in topographical memory for a long-term period. However, these data were gathered through a limited set of tasks (mainly tapping survey-type memory) performed in real-world environments, which were not entirely controlled from a methodological point of view. For these reasons, in the present study the forgetting rate of route and survey memory was investigated in a virtual environment.