While some women still go for the strong-jawed macho man, many know that he might not be the best choice as a long-term mate.
Instead, women see such features as a prominent jaw and larger nose as signs that a man is less likely to remain committed and faithful, according to new research published in the journal Personality and Individual Differences.
The study adds to a growing body of research probing the underlying psychology of our mating choices and rules of attraction. One goal of such research is to unlock the mysteries of how mate selection affects the evolution of the human species.
"We've a lot to figure out about what's been driving our facial preferences over the millennia," says study co-author Lynda Boothroyd.
In her new study, a joint effort by Durham and St. Andrews universities in the United Kingdom, Dr. Boothroyd and three colleagues asked women to ascribe various personality traits to a series of photographs of men.
The women were asked to pick which faces were the most ambitious, likely to be committed to a long-term partner, faithful to a long-term partner, socially dominant, the better parent, the warmest and the most wealthy.
Men with feminine-looking features - defined as more curved eyebrows and a more arched forehead - were more likely to be perceived as being committed to a partner and to parenting.
Men with masculine features scored higher in only one area: They are socially dominant.
Evolutionary psychologists used to think that women were attracted to masculine-looking men because their features were also markers for a concept called immunocompetence. In this hypothesis, it was believed that, since testosterone places extra strain on the immune system, when a woman encountered a very masculine-looking man she would perceive that he must have a strong immune system in order to have survived.
And because good immunity is partly inherited, even if she knew that the masculine man wouldn't be home much, at least her kids would have a better chance of being healthier and surviving.
This is the trade-off that sounds so familiar to modern women: Pick a hunky guy who is a bit of a rolling stone, or a less hunky man who is a sweet, caring father.
But Dr. Boothroyd's study, calling into question some of the earlier research, found that the ideal man is actually a third option: the healthy-looking man.
Defined as possessing such features as healthy skin and not too much subcutaneous fat, the healthy man is perceived by women as having the positive attributes of both the testosterone man and the man with feminine facial traits.
"Facial health is seen across the board as a good thing," Dr. Boothroyd says.
"They're seen as dominant and ambitious and wealthy, but also as faithful and warm and as good fathers."
Yet, how to explain women choosing those unsuitable, macho, alpha types? Many do.
Ovulating women have an increase in masculine preference, Dr. Boothroyd says, as do women who are already in a committed long-term relationship, "the idea being that they're already in a relationship, so they're not looking for a long-term partner."
Women with high self-esteem also choose more masculine partners, which may be because "they've got more in the bank to negotiate."
But they're not choosing them for their immunocompetence, Dr. Boothroyd says. Instead, they're attracted for reasons more directly related to the man's alpha-male status. Their genes might not technically be better, but since they belong to a socially dominant male, women perceive the men as having other desirable attributes.
So the next step is to take a harder look at what those genetic benefits might be. The "sexy-son" hypothesis, which dates back to the 1920s, is one possibility, Dr. Boothroyd says.
The premise: If a male is reproductively successful, it's advantageous to mate with him because he should produce sons who are also reproductively successful. "Sexy sons actually give their mothers more grandchildren," she says. These women are making a trade-off so their genes "can hijack a ride along with his and spread through the population."
Not that most women can parse out the exact reasons for their attractions - why, for instance, they might choose a dominant, masculine, George Clooney type or a more commitment-worthy pretty boy like Scrubs star Zach Braff. Or a healthy Tiger Woods.
"Humans are very complicated," Dr. Boothroyd says. "They don't always do what their underlying emotional urges are driving them to."