Cite as:
Tse  P U, Caplovitz G P, 2006, "The bar – cross – ellipse illusion: Alternating percepts of rigid and nonrigid motion based on contour ownership and trackable feature assignment" Perception 35(7) 993 – 997
Download citation data in RIS format

Last but not least
The bar – cross – ellipse illusion: Alternating percepts of rigid and nonrigid motion based on contour ownership and trackable feature assignment

Peter U Tse , Gideon P Caplovitz

Abstract. We present a new multistable stimulus generated by continuously rotating an ellipse behind four fixed occluders. Despite the stimulus remaining constant, observers can alternate between one of four percepts: (1) a continuously morphing cross; (2) two independent perpen- dicular bars oscillating in depth; (3) a rigidly rotating ellipse observed behind the occluders; (4) a fixed cross observed through a continuously rotating, elliptical aperture. Interestingly, the initial percept naive observers tend to see is percept 1, which is the only nonrigid motion percept. This appears to be a violation of the hypothesized `rigidity heuristic' in which rigid motion percepts tend to be perceived over retinally equivalent nonrigid ones. Here, we describe the relationships between each of the percepts and the assignment of contour ownership and figure/ground segmentation.

This article has supplementary online material: colour figure and movie

 Full-text PDF size: 202 Kb

 References  14 references, 6 with DOI links ()