Spatiotemporal relationships in a dynamic scene: stereomotion induction and suppression.

We establish the existence of purely stereoscopic motion induction, i.e., perceived depth motion induced into a fixed-disparity target by disparity changes in a surround region. The stimuli were dynamic autostereograms consisting of a target and a surround, both consisting of horizontal lines of discs. We explored the stereomotion induction process by (i) direct estimation of the perceived distance moved, (ii) a cancellation technique with compensatory target motion, and (iii) extension of the compensatory motion into the zone beyond the null point. Adding compensatory stereomotion to the target reduced the induced motion experience to a null point. Beyond the cancellation point, two surprising results were obtained; perceived motion in the target increased, while the surround stereomotion perception was almost suppressed over a wide range of disparity changes (reciprocal stereomotion suppression). A model of the target/surround interactions was developed in the context of dynamic organization principles operating in stereomotion perception and misperception.