Abstract
We introduce a novel illusion – the Bendy Bars illusion, in which stationary bars (i.e. a vertical sinewave grating) appear to bend when dynamically occluded by translating Gaussian ovals. This effect, however, only becomes visible once specific parameters have been met: The illusion is strongest when there are multiple vertically elongated ovals drifting horizontally back and forth across the bars and the relationship concerning spatial frequency and distance between each oval should be such that would allow visibility of individual bars in-between the moving elements. Furthermore, the effect appears to be strongest at lower speeds, also likely due to visibility issues. Why does the illusion occur? As the occluding Gaussians move back and forth there is ambiguity as to which object: the occluders or the bars, the corresponding motion energy belongs to. Although the exact relationship between the motion signals present in the stimulus and the illusory deformation seen in the background remains to be elucidated, we hypothesize that the illusion arises due to a misbinding of motion signals whereby some of the motion energy from the drifting ovals is misattributed to the bars causing the illusion of a global bending in the direction of motion.
Meeting abstract presented at VSS 2016