SPATIAL INTERACTIONS IN PERCEIVED SPEED

Previous research has shown that the perception of motion within a loc al region is influenced by other motions within neighboring areas (eg induced motion). Here, a study is reported of the perceived speed of d ots moving within a circular target region, which was surrounded by ot her motions within a larger surrounding area. The perceived speed of t he central dots was found to be fastest when the surround was stationa ry; it became slower as the speed of motion in the surround was increa sed. This decrease in the perceived target speed with increases in sur round velocity occurred regardless of whether the direction in which t he surround moved was the same as or opposite to the motion of the tar get region. This result cannot be explained by using simple models of perceived speed that depend only upon such factors as the magnitude of relative motion between center and surround. The spatial area over wh ich these motion interactions occur was also investigated.