The sum of induced and real motion is not a straight path

Abstract

The apparent motion path of a stimulus undergoing simultaneous real motion and orthogonal induced motion (1M) was measured by having subjects draw the perceived path. The average path was not a straight line, but was curved away from the direction of inducer motion. This result is consistent with a previous finding that 1M magnitude increases with stimulus duration, and with a theory that attributes 1Mto the suppression of reflexive eye movements. Implications are discussed for research in which the apparent slope of the motion path of a stimulus undergoing simultaneous 1M and real motion is used as a measure of 1M. © 1988 Psychonomic Society, Inc.