Spatial Displacement, but not Temporal Asynchrony, Destroys Figural Binding

Manfred Fahle and Christof Koch

What are the elementary features that the brain uses to bind spatially distinct parts in a visual scene into an unitary percept of an "object"? The Gestalt psychologists emphasized the extent to which motion, colour, luminance or spatial arrangement contribute towards object formation. Little is known about the role of time per se, rather than motion, in constituting an object. In particular, does the visibility or saliency of an object change if the various parts making up the object are not presented simultaneously? Using a simple experimental design, we show that very small spatial displacements can significantly influence the saliency of an object while large temporal asynchrony has no significant effect.