Abstract
Environment-based frames of reference are established by directional cues in the environment. The environment contains many directional cues, which for a given task vary in their proximity to the task-relevant objects. Judging handedness is a task that employs environment-based reference frames. The purpose of the present study was to determine whether more local or more global environment-based frames of reference are selected for use when comparing the handedness of two objects. An object comparison task was employed in which subjects were required to judge, as quickly as possible, if one object matched a hole in a second object. Because of the spatial dimensions of both objects, the task implicitly required a comparison of the objects' handedness. Both objects were embedded in a shared global frame of reference, and each object was individually embedded within its own more local frame of reference. The angular disparity between the orientations of the objects, relative to various viewer- and environment-based frames of reference, was manipulated. Response time was examined as a function of angular disparity. Response times were fastest when the objects were aligned relative to their more local frames of reference. Response time increased as the angular disparity between the objects relative to their local frames of reference increased. When two competing environmental frames of reference were available, the objects were mentally rotated into alignment relative to the most local environment-based frame of reference.