Barbara Tversky

Within psychology, at least two research communities study spatial cognition. One community studies systematic errors in spatial memory and judgement, accounting for them as a consequence of and clue to normal perceptual and cognitive processing. The other community studies navigation in real space, isolating the contributions of various sensory cues and sensori- motor systems to successful navigation. The former group emphasizes error, the latter, selective mechanisms, environmental or evolutionary, that produce fine-tuned correct responses. How can these approaches be reconciled and integrated? First, by showing why errors are impervious to selective pressures. The schematization that leads to errors is a natural consequence of normal perceptual and cognitive processes; it is inherent to the construction of mental spaces and to using them to make judgments in limited capacity working memory. Selection can act on particular instances of errors, yet it is not clear that selection can act on the general mechanisms that produce them. Next, in the wild, there are a variety of correctives. Finally, closer examination of navigation in the wild shows systematic errors, for example, over-shooting in dead reckoning across species. Here, too, environments may provide correctives, specifically, landmarks. General cognitive mechanisms generate general solutions. The errors inevitably produced may be reduced by local specific sensori-motor couplings as well as local environmental cues. Navigation, and other behaviors as well, are a consequence of both

Although people can take spatial perspectives different from their own, it is widely assumed that egocentric perspectives are natural and have primacy. Two studies asked respondents to describe the spatial relations between two objects on a table in photographed scenes; in some versions, a person sitting behind the objects was either looking at or reaching for one of the objects. The mere presence of another person in a position to act on the objects induced a good proportion of respondents to describe the spatial relations from that person’s point of view. When the query about the spatial relations was phrased in terms of action, more respondents took the other’s perspective than their own. The implication of action elicits spontaneous spatial perspective-taking, seemingly in the service of understanding the other’s actions.