Abstract
Object position and identity has been dissociated using spatial memory tasks involving the reproduction of object layouts. We explored this dissociation through a spatial task involving changes in viewpoint. In two experiments, subjects (Ss) were presented with an array of objects positioned on a circular table that either remained stationary or was rotated. In Exp 1, two sets of objects were used: identical cylindrical objects or different cylindrical objects. Further, the number of objects presented was varied from four to seven. For each trial, following learning, one of the objects was moved to a new position and Ss were required to identify which object had moved. Results showed that for identical objects, Ss' reaction time and error rate were similar regardless of the number of objects presented. However, for different objects, Ss' performance decreased as the number of objects increased. This suggests that Ss tend to take advantage of the global properties of the visual scene if the scene is composed of identical objects. However, if the scene is composed of objects with different identities, Ss tend to focus on local spatial properties. In Exp 2, only different objects were used. In Condition one, a single object was moved to a new position. In Condition two, one of the objects was replaced with a novel one. Subjects were required to identify which object had changed. An interaction effect was observed between spatial properties (position and identity) and sex. This provides further support that position and identity may be differentially processed.
Key Subject Grant, School of Psychology, SouthWest University