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George S W Chan, Yvonne Chang, Hong-Jin Sun; Encoding of different environmental features with or without spatial updating. Journal of Vision 2007;7(9):1053. doi: 10.1167/7.9.1053.
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© ARVO (1962-2015); The Authors (2016-present)
Wang and Spelke (2000) have shown that certain features of an environment are encoded egocentrically, whereas others are encoded allocentrically. We studied directional judgments of environmental features (objects and corners) from viewpoints that were either aligned or misaligned with the originally learned viewpoint. Further, we explored the role of spatial updating in determining the type of spatial processing.
Subjects were brought to a learning position in a four-sided, irregularly shaped room and learned the locations of four corners and four different objects. They were then blindfolded and led to the centre of the room either along a direct path (providing spatial updating) or along a disorienting path. They were then required to point in the directions of the corners and objects while imagining themselves at one of two testing viewpoints (aligned or misaligned with the learning viewpoint).
The results showed that absolute error for both corners and objects was higher from the misaligned viewpoint compared to the aligned viewpoint regardless of whether subjects were disoriented or not, suggesting a tendency for egocentric processing. However, for configuration error, when subjects were not disoriented, both corners and objects showed no difference between viewpoints. This discrepancy in results between absolute and configuration error when subjects were not disoriented suggests that subjects can maintain the relative layout of the features but not the absolute direction of the features when the testing viewpoint changed. When subjects were disoriented, configuration error was higher from the misaligned viewpoint compared to the aligned viewpoint for corners but not for objects.
The manner by which different features are processed can be conceptualized as falling on different positions along a continuum between pure egocentric and pure allocentric spatial representations. Overall the availability of spatial updating and the type of spatial features can both impact the characteristics of spatial representations.
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