ARI SHAPIRO, HOST:
How did facial hair, specifically beards, evolve? Turns out actual scientific research on beards is patchy. Earlier this year, researchers got to know how beards are perceived by children. And since it's the time of year for big family gatherings, we thought we would revisit this report by NPR's Nell Greenfieldboyce.
NELL GREENFIELDBOYCE, BYLINE: For most of human evolution, dudes had beards.
NICOLE NELSON: Until very recent history, beards were a very prominent element of men's faces. And so we must have expectations related to those. And it turns out that adults do.
GREENFIELDBOYCE: Nicole Nelson studies face perception at the University of Queensland in Australia. She says past work by her colleague Barnaby Dixson has shown that beards make men look older, stronger and more masculine, at least to adults.
NELSON: And so we were wondering whether or not all of those expectations emerge in adulthood or if they're there throughout our lives.
GREENFIELDBOYCE: Her team tested this in over 400 kids, from toddlers to teenagers. Researchers would show kids two photos side by side; a man with a beard and the same man clean-shaven.
NELSON: And then we just ask kids, so which man looks stronger? Which man looks older? Which man looks best?
GREENFIELDBOYCE: It turns out that even little kids associated beards with being older and stronger. But when asked which face was best, young kids were strongly anti-beard.
NELSON: As early as you know, 1 year, 9 months, they dislike beards. And kids, as they got older, up to about 13 years, continued to dislike beards even more.
GREENFIELDBOYCE: Interestingly, around the age of puberty, young people changed. They started to like beards more and judged them more like adults do. And experience seems to count too. Kids whose fathers had beards felt more warmly towards facial hair. The study appears in the journal Evolution and Human Behavior. Nelson says for men, beards offer certain advantages.
NELSON: I think it's a good move if you want to kind of boost your manliness, right? - if you want to look a little more dominant, you want to look a little bit older.
GREENFIELDBOYCE: The downside is that children may be slightly afraid of you.
Nell Greenfieldboyce, NPR News.
(SOUNDBITE OF MR. SCRUFF'S "KALIMBA") Transcript provided by NPR, Copyright NPR.