Abstract
Ambiguous structure-from-motion stimuli have been used by vision scientists for many years in studying conscious visual awareness. We have recently developed an ambiguous, rotating, biological figure; the ‘rotating walker’ appears to randomly alternate between walking in clockwise and counter-clockwise directions (Jackson et al., 2007, Perception, 36, 74). As with other ambiguous figures, observers experience high rates of percept-reversal when the figure is viewed over long periods, and this ‘multistability’ disappears when blank intervals interrupt the trial period; observers consistently stabilise to one or other percept. What may be unique to the rotating walker is the fact that it represents a ‘biological’ form - when the walker is presented at right angles to the viewer at onset, the initial direction of rotation is often interpreted as that which is compatible with an ‘approaching’ or ‘forward-moving’ figure. Such an effect is consistent with perceptual biases previously found with standard biological motion stimuli (Vanrie et al., 2004), and may reflect the working of a fast-acting perceptual “life-detector” mechanism suggested to exist in the human visual system (Troje & Westhoff, 2006).
SJ is supported by the Irish Research Council for Science, Engineering & Technology (IRCSET), funded by the NDP.