The perception of shrinking in apparent motion.
Apparent motion was produced using two triangular patterns of different sizes, each exposed for 100 msec, with a 50-msec interstimulus interval and 200-msec recycle interval. The triangles were aligned either on center or on the midpoints of the bases. In Experiment 1, filled, outline, and three-dot triangles were viewed over four backgrounds: a blank illuminated field, and texture gradients constructed from horizontal lines, perspective lines, or a combination of these (full texture). In Experiment 2, outline and dot triangles were presented in one of three orientations: base down, base right, and base up over a blank background. Subjects made two forced-choice responses: apparent size was categorized as shrinking or not shrinking, and apparent motion was categorized as motion in depth or motion in a fixed frontal plane. The type of alignment was the major determiner of responses. When the midpoints of the base were aligned, the predominant response described a shrinking object in a fixed position in depth. When the centers were aligned, the predominant response described an object of constant size moving in depth.
Hershenson
M
M
Department of Psychology, Brandeis University, Waltham, MA 02254-9110.
D000328:Adult; D001288:Attention; D003867:Depth Perception; D004193:Discrimination Learning; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception; D009903:Optical Illusions; D009949:Orientation; D010364:Pattern Recognition, Visual; D011601:Psychophysics; D012858:Size Perception