Modification of saccade-contingent visual mislocalization by the presence of a visual frame of reference.
The effect of three kinds of background visual field on saccade-contingent mislocalization was compared so as to explore the critical factor responsible for visual stability during saccadic eye movements. A large mislocalization observed in the dark (DARK condition) was substantially decreased when a faint frame pattern was projected against the dark background (FRAME condition) as well as when the background screen being illuminated (LIGHT condition). Large mislocalization in the DARK condition occurred both when targets were presented just before the beginning of a saccade and when they were presented at the end of the saccade, irrespective of the position at which the target was presented. In contrast, in the FRAME and LIGHT conditions, mislocalization appeared to depend on target position. Mislocalization of targets presented immediately before the saccade onset diminished when they were presented near the saccade goal, whereas mislocalization of targets presented at the end of the saccade diminished when they were presented near the original fixation point. It was concluded from these results that the subject made use of the frame and the illuminated background as a visual cue for exocentric localization of the target, and that a saccade-contingent shift of visual attention was involved in producing the selective diminution of mislocalization observed in FRAME and LIGHT conditions.
Honda
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Department of Psychology, Faculty of Humanities, Niigata University, Japan.
D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D012438:Saccades / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors