External Cue Effects on Memory for Spatial Location within a Rotated Task Field

Fitting, Wedell and Allen (2007) demonstrated that although memory for location within a small two-dimensional task field is largely independent of cues when orientation is fixed, it is highly dependent on cues when orientation varies by rotating the task field on a majority of trials. Their analysis focused only on 0 rotation trials. The current investigation aimed to understand the spatial estimation process under conditions of actual rotation and thereby analyzed the cue effects for the 30, 90, and 160 rotation trials of that experiment. Results indicated strong cue-based angular bias effects, which were modeled as resulting from use of cues as category prototypes. Unique to rotation trials, the number of inferred protypes did not generally correspond to the number of cues. In the one-cue condition, there was evidence that an additional prototype was generated at a location opposite the single cue, representing a “phantom” prototype. In the three-cues condition, there was evidence that only two cues served as prototypes biasing estimation. Absolute error in spatial memory was also strongly reduced as a function of proximity to cues, implicating the role of cues in anchoring fine-grain memory. In contrast to the bias measure, effects on absolute error were more directly tied to actual cue locations.