Motion parallax, relative size, and Benussi effect.

Abstract

Many observers perceive depth when a configuration of nonconcentric circles is rotated on a disc. While it has been suggested by a number of investigators that motion parallax has a role in generating this phenomenon, the supporting data are equivocal. The current study proposed that the ambiguity regarding the role of motion parallax may have arisen because there are contradictions between relative size cues and motion parallax cues in the configuration of rotating circles. However, with 17 undergraduate observers, apparent depth was no more reliably reported with consistent cues of motion parallax and relative size than when these cues were contradictory.