Family resemblance. Women and men tend to choose spouses who look like their parents.

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Finding a Guy Who Looks Like Dear Old Dad

"You have such full lips, just like my mom." That pickup line probably won't get a guy many dates--but it's likely to be true. A new study of facial features adds to mounting evidence that a man tends to choose a girlfriend who resembles his mother, and a woman picks a boyfriend who looks like her father.

Researchers are on to something, says Randy Thornhill, an evolutionary psychologist at the University of New Mexico in Albuquerque: "It's more than just a little fluke."

The findings have their roots in studies of geese carried out in the 1930s. Ethologist Konrad Lorenz found that when he raised the birds, they followed him around like a mother. He could even convince goslings that a ball was mom if the ball "led" the flock of tiny birds within days of hatching. Since then, the behavior, known as imprinting, has also been linked to mate choice. Male lambs raised by goats, for example, grow up as rams that battle for the affection of goats, not sheep.

Imprinting seems to exist in humans too. Studies show that men and women born to older parents find older faces more attractive, and women will favor photographs of men whose faces resemble their fathers. People have also judged photos of men and their fathers-in-law as looking similar, further suggesting that women marry men who look like their dads.

Hoping to quantify this effect in both men and women, Tamás Bereczkei, an evolutionary psychologist at the University of Pécs in Hungary, measured 14 facial proportions, such as lip fullness, nose length, and jaw width, of 312 people from 52 families in Hungary. The team found that men and their partners' fathers looked more similar to each other than to random men in the study: The men shared significant correlations for seven areas of the face, mainly in features around the eyes and nose. Women and their partners' mothers also resembled each other, with significant correlations for five of the facial features, mostly around the jaw.

Bereczkei says the results, published online today in the Proceedings of the Royal Society B, indicate that people are probably not simply relying on familiarity as a cue when picking dates, because children seem to use only their opposite-sex parents as a model for the perfect spouse.

Using mom or dad as a mating guide may be evolutionary insurance against mating with the wrong species, a possible throwback to a time when multiple hominids lived together, says Lisa DeBruine, an evolutionary psychologist at the University of Aberdeen in the U.K. Or, she says, it could be a way to balance the benefits of finding a similar mate, who is likely to share some beneficial genes and adaptations with you, against the pitfalls of incest.

Boguslaw Pawlowski, an anthropologist at the University of Wrocław in Poland, says that it's still unclear what role imprinting plays relative to other factors that influence mate choice. For example, people often find symmetrical faces and bodies attractive because they are thought to signal good health (ScienceNOW, 18 August), he notes. So what's a girl to do when she has an asymmetrical dad: Will the influence of imprinting overrule her desire for a sexy, symmetrical man? That's a good topic for future research, says Bereczkei.