Abstract
Visuospatial reasoning is the ability to generate, retain, retrieve, and transform visual images (Lohman 1993). This visual behavior allows us to understand and navigate our physical environment, and in doing so, use mental rotation, which is the ability to visualize an object at various viewpoints (Shepard & Metzler 1971). While it has been established that eye movement patterns correlate with visuospatial performance (Just & Carpenter 1976; Mast & Kosslyn 2002), this was the first study which examined mental rotation without eye movements. Human subjects (n=48) performed a mental rotation task by viewing paired geometrical shapes (Peters & Battista 2008) oriented at three possible disparity angles (50, 100, 150 deg) from one another, and deciding whether they were identical or not. A total of six blocks of 60 trials each were presented. Participants alternated blocks of free viewing with eye movements, and holding their gaze on a central fixation point. Proportion correct and trial response times were measured. Overall, subjects were consistently more successful, but slower, at the task using eye movements than without. During free viewing, proportion correct decreased across disparity angles, and reaction times were static. Without eye movements, both proportion correct and reaction times peaked at the intermediate disparity angle (100 deg), and decreased for the two extreme disparities. These findings indicated that free viewing is important for mental rotation, but at the expense of time. During covert viewing, reaction times also increased with accuracy except for the greatest disparity angle (150 deg). Resolving large orientation disparities between objects may require the utilization of eye movements, since accuracy was close to chance without them and subject reports were in line with this result. Therefore, fixed gazed viewing was more sensitive to task difficulty. This conclusion has further emphasized the importance of eye movements during mental rotation.
Meeting abstract presented at VSS 2016