There is no single sexy chin, study shows Apr. 9, 2013 - There is no single sexy chin. That's the conclusion of a new Dartmouth College global study of male and female preferences for facial characteristics of the opposite sex. The results, which contradict the notion that human beauty is universal, are published in the journal PLOS ONE. The researchers studied chin shapes among 180 male and female skeletons in nine areas in Australia, Africa, Asia, and Europe to test the universal facial attractiveness hypothesis. The hypothesis proposes that some facial features are universally preferred by the opposite sex because they are reliable signals of mate quality. But the researchers found significant geographic differences in the chin shapes. The results challenge Darwin's theory, at least with regard to chin shape, that sexual selection results in the proliferation of physical characteristics that provide a competitive advantage in the struggle to find mates. "If preferences for particular chin shapes are universal in the strict sense, and these preferences influence the evolution of the chin, then chin shapes should not differ significantly between geographic regions," the authors wrote. But our results suggest that chin shape is geographically variable in both sexes, challenging the notion of universal sexual selection on chin shape. Zaneta M. Thayer, Seth D. Dobson. Geographic Variation in Chin Shape Challenges the Universal Facial Attractiveness Hypothesis. PLoS ONE, 2013; 8 (4): e60681 DOI: 10.1371/journal.pone.0060681