Dependence of illusory motion on directional consistency in oblique components

Pinna and Brelstaff (2000 Vision Research 40 2091-2096) reported a motion illusion on viewing two concentric circles consisting of quadrangular components with black and white sides on a grey background. Our results suggest that the illusion is based on the integration of motion signals derived from oblique components, and on the consistency in the direction among those components. Furthermore, arrays of these oblique components can elicit the perception of motion not only for the oblique components themselves, but also for other objects in the picture. We propose that the motion illusion depends not only upon detection of the illusory motion signal at each local oblique component, but also upon the accumulation of the signal all over the stimulus configuration.