The Subjective Direction of Gaze Shifts Long Before the Saccade
Subjects in eye movement experiments sometimes report that they have moved their eyes to some location before their eyes have actually moved (Deubel and Schneider, 1996). We investigated this by presenting a brief test stimulus at various points in time after directing subjects to make a saccadic eye movement to a peripheral cue. The subjects had to report where they were looking when the test stimulus was presented. We found that visual stimuli presented at the saccade target location as early as 250 ms before sac-cade onset were reported as occurring after the saccade. In a second experiment subjects performed, intentionally, a saccade to a static cue. Also under this condition, subjects reported to look at the future saccade target location long before the saccade actually occurred. The data show that subjects are unaware of the time when they make even a large saccade, and that they have no explicit knowledge of the retinal position of stimuli. Rather, they mistake movements of visual attention for movements of the eyes.
KeywordsTest Stimulus Visual Attention Saccade Target Test Circle Saccade Onset
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