Describing perceptual information about human growth in terms of geometric invariants

Abstract

Three experiments are reported that examine the perceptual information by which growth of a human head is distinguished from other possible styles of change. The results demonstrate that the perception of growth may be based on a specific set of invariant geometric relations described previously by Mark, Todd, and Shaw (1981). When observers are asked to judge which of two facial profiles looks older, they are surprisingly accurate if the profiles are related by an appropriate transformation, but their performance is no better than chance if the profiles are related by an inappropriate transformation. If, on the other hand, they are instructed to judge whether a pair of profiles is the same or different, the differences produced by the appropriate and inappropriate transformations are equally discriminable. © 1985 Psychonomic Society, Inc.