European Conference on Visual Perception edition:31 location:Utrecht date:24-28 August 2008
In recent experiments [Ekroll et al, in press Journal of Vision 8(4.31) 1 - 22] with two-element apparent motion stimuli it was found that pure phi (also known as shadow motion or omega motion) depends on three temporal variables (stimulus onset asynchrony, temporal duty cycle and local interstimulus interval). Violations of either of these constraints lead to specific competing motion and non-motion percepts. Here, we report the results from experiments investigating how these findings generalise to multiple-element stimuli like those used by Steinman et al (2000 Vision Research 40 2257 - 2264). Using displays with eight instead of just two stimulus elements, a similar pattern of results was found. In particular, the same three variables constrain the occurrence of pure phi but the critical thresholds in terms of stimulus onset asynchrony and local interstimulus interval vary systematically.