Perceptual-binding in a rotating Necker cube: The effect of context motion and position.

Previous studies have shown that spatial context influences the perceptual interpretation of ambiguous figures such as the Necker cube; however, the properties that mediate the influences of an unambiguous spatial context have yet to be investigated. Here we consider the effect of the motion and position of an unambiguous rotating skeleton cube on the perceived motion direction of an ambiguous rotating Necker cube. We aimed to determine whether the motion of the two figures could be perceptually bound, and if it could, to determine the properties of the binding. We employed a novel procedure analogous to reverse correlation to establish the correlation between the rotation directions of the context and the perceived rotation directions of the target, across 32s trial presentations. Our results showed that changes in the rotation direction of the context triggered above-chance changes in the perceived rotation direction of the target. However, the relative speeds of rotation of the context and target had little effect on the correlations. Position on the other hand had a significant effect: correlations were higher when the context was below compared to when above the target. Our results reveal that change-synchrony not common fate is the factor mediating perceptual motion binding between the context and Necker cube. We also suggest that prior knowledge of friction forces could underlie the position dependency of the context and Necker-cube correlation.