Approximation in Perceptual Completion

Normally, the perception of complete visual shapes given incomplete sensory evidence can be explained by interpolation; i.e., by the smooth monotonic connection of literally represented contour stimuli. However, in limiting conditions (e.g., the Gerbino illusion pattern) such a connection is impossible, forcing the visual system to either violate smoothness and monotonicity constraints or relax the literal representation assumption. I review evidence that figural completion may involve visual approximation rather than interpolation, and discuss the implications of such a view for perceptual theory.