Abstract
Measures of perceived size, perceived distance, and perceived stimulus speed of rotating spirals were obtained in addition to the duration of the spiral aftereffect. Two major conditions were used: Size Constant—a 4-in. spiral was positioned to subtend visual angles of 1/2°, 1°, 2°, 4°, or 8° with 7 rates of retinal speed (10-100 minarcs/sec.) used at each angle; Angle Constant —3 sizes of spirals were positioned so that each subtended visual angles of 2°, 4°, and 8° with physical speed held constant (75 rpm) in one case and retinal speed (45 minarcs/sec.) held constant in another. SAE durations were significantly affected by low retinal speeds, by small visual angles and by perceived size per unit of retinal size.
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