Abstract
Perceptual and motor systems can be faced with ambiguous information and then have to choose between different interpretations or reactions. Often these alternatives involve decisions about directions and anisotropies have been reported for different tasks. Here we measured inter-individual differences and temporal stability of directional preferences in eye movement, motion perception and finger movement tasks. In all tasks, stimuli were created such that observers had to decide between two opposite directions in each trial. Preferences were measured at 12 axes around the circle. In saccade and finger tasks, subjects had to move either their eyes or an analog joystick to one of two stationary stimuli, displayed at opposite locations in the visual field. In a pursuit task, subjects had to pursue one of two overlapping random-dot-kinematograms, moving in opposite directions. In two perceptual tasks, subjects had to indicate the perceived motion direction of ambiguous apparent motion or structure-from-motion stimuli. There were clear directional preferences in all tasks. The strongest effects were observed in tasks that involved motion, like smooth pursuit eye movements, apparent motion and structure-from-motion. The weakest effects were observed in the saccadic eye movement task. Although there were consistent preferences across observers in some of the tasks, there was also considerable variability in preferred directions between observers. These individual preferences were stable over twelve weeks. Observers with strong directional preferences in the saccadic and smooth pursuit eye movement tasks had shorter latency costs for trials with two targets compared to trials with one target. These results show that individually stable directional preferences exist in a range of perceptual and motor tasks. The latency benefits for observers with strong preferences suggest that directional preferences are advantageous for solving target conflicts.
Meeting abstract presented at VSS 2014