April 15, 2013
Chin Preference Changes Across Several Populations
Lee Rannals for redOrbit.com — Your Universe Online
A new study published in PLOS One suggests facial preferences across different populations vary.
Northwestern University researchers tested the assumption that the presence of chin shape in picking a mate is consistent across human populations. However, they found when tested, this theory didn't hold true.
"This suggests that either sexual selection hasn't been important in shaping chin shape in humans or that facial preferences differ between populations," said Zaneta Thayer, a doctoral student in anthropology at Northwestern University and lead author of the study.
This is the first study to examine the universal facial attractiveness theory not using data that considers facial preference, but instead using actual patterns of variation in shape of traits themselves.
One theory behind universal facial attractiveness is that some facial features are universally preferred because they may be perceived as a reliable sign for picking a quality mate. However, the team also found choosing a mate isn't just about judging a book by its cover, concluding how we choose a mate is based on more than attractiveness.
"We hope that our study will encourage evolutionary psychologists to consider how their research on facial attractiveness actually influences 'evolutionary successes as measured through number of offspring produced," Thayer said. "By evaluating patterns of variation in actual trait distribution within and between populations, we can get a better sense of what previous selection has actually looked like in these populations."
In 2010, Thayer and colleagues evaluated competing theories for the adaptive significance of the human chin. She said humans are the only primates with a chin, which is one of the unique characteristics that define our species.
"We found that the indigenous Australian population had the most unique chin shape pattern relative to other populations," Thayer said. "That said, even after removing this population from the analysis, significant differences remained between other populations."
She said scientists should think more critically about whether facial preferences inform us about actual mate success in humans.
"Since humans have evolved to be such socially complex individuals, it is not surprising that their mate decisions are based on more than just attractiveness," she said.
A few years ago, another study argued it wasn't physical attraction, but competition that helped our ancestors come together. Researchers from this study hypothesized that men have thicker jawbones because men would hit each other, and the thickest-boned men were the ones who survived. They also said men have more robust skulls and brow ridges than women due to competition.