An orientation illusion analog to the rod and frame: Relational effects in the magnitude of the distortion

Abstract

Using a printed configuration of a rod enclosed by a tilted frame, an orientation illusion analog to the classical effect was obtained. In the first experiment it was shown that the distortion obtained in this array varies in direction and magnitude as a function of degree of frame tilt, in a manner that is globally similar to that usually obtained in more traditional methods of measurement. The second experiment indicates that relational factors determine the magnitude of the effect, with increasing rod and frame separation resulting in diminished apparent tilt of the rod. Possible interactions between such an orientation illusion effect and visual-vestibular contributions to the rod and frame are discussed. © 1986 Psychonomic Society, Inc.