Abstract

Pairs of dots in apparent motion are strikingly mislocalized in the direction of the motion. If two pairs of dots in horizontal apparent motion, moving in opposite directions are positioned one over the other (forming a tall rectangle), they do not appear vertically aligned. The rightward moving dots appear mislocalized to the right and the leftward moving dots appear mislocalized to the left. We have investigated this illusion focusing on the influence of added perturbing dots presented to reinforce or oppose the apparent motion created by the test dots. The apparent motion of the test dots can be either nulled or enhanced by such perturbing dots.¹ When the test-dot apparent motion is nulled, the mislocation is abolished along with the motion. Likewise, the enhancement of test-dot apparent motion by a third dot on a consistent trajectory increased the mislocation. These observations support the idea that the motion of moving objects is signalled by the motion system rather than by static local signs² and they also indicate that the motion system integrates or recruits information from multiple views (rather than only two views) of the moving stimulus.

© 1991 Optical Society of America