Abstract
In the visuomotor mental rotation (VMR) task, participants point to a location that deviates from a visual cue by a predetermined angle. This task elicits slower reaction times (RT) than standard tasks wherein the visual cue is spatially compatible with the movement goal. RTs are reduced when the standard and VMR responses elicit a degree of dimensional overlap (i.e., 0° and 5°) or when the transformation involves a perceptually familiar angle (i.e., 90° or 180°; Neely & Heath, submitted). One caveat to this finding, however, is that past work examined standard and VMR responses in separate blocks of trials. Thus, RT differences between tasks not only reflect the computational demands of the transformations, but also the temporal cost of visuomotor inhibition. The present work used a randomized task design to isolate the magnitude of the RT difference between standard and VMR tasks across a range of equally spaced angles. Between-task difference scores were least for small (i.e., 30°) and perceptually familiar (i.e., 90 and 180°) angles relative to large and less familiar angles (i.e., 60, 120, 150, and 210°). This finding suggests RTs reflect the time required to prepare and inhibit an automatic motor response to the visual cue and then compute the requisite transformations for the response. Moreover, the rate at which the response is prepared is influenced by the angular disparity between standard and VMR responses and the perceptual familiarity of the transformation angle.Acknowledgments: This research was supported by NSERC as well a Graduate Thesis Award from The University of Western Ontario.