Compatibility of basic social perceptions determines perceived attractiveness.

The human body's shape and motion afford social judgments. The body's shape, specifically the waist-to-hip ratio, has been related to perceived attractiveness. Early reports interpreted this effect to be evidence for adaptation, a theory known generally as the waist-to-hip ratio hypothesis. Many of the predictions derived from this perspective have been empirically disconfirmed, leaving the issue of natural selection unresolved. Knowing the cognitive mechanisms undergirding the relationship between judgments of attractiveness and body cues is essential to understanding its evolution. Here we show that perceived attractiveness covaries with body shape and motion because they cospecify social percepts that are either compatible or incompatible. The body's shape and motion provoke basic social perceptions, biological sex and gender (i.e., masculinity/femininity), respectively. The compatibility of these basic percepts predicts perceived attractiveness. We report evidence for the importance of cue compatibility in five studies that used diverse stimuli (animations, static line-drawings, and dynamic line-drawings). Our results demonstrate how a proximal cognitive mechanism, itself likely the product of selection pressures, helps to reconcile previous contradictory findings.