The psychology research indicates that women are more like men regarding sexuality and attraction than people previously thought.
We explore some of the major similarities — and differences — between the sexes, and how men can use them to appear more attractive.
Rutgers University anthropologist and bestselling author Helen E. Fisher says that from the depth of the Amazons to the cafés of Paris, women signal interest with a remarkably similar sequence of expressions.
As she shared on Psychology Today, it goes like this:
First the woman smiles at her admirer and lifts her eyebrows in a swift, jerky motion as she opens her eyes wide to gaze at him. Then she drops her eyelids, tilts her head down and to the side, and looks away. Frequently she also covers her face with her hands, giggling nervously as she retreats behind her palms.
This sequential flirting gesture is so distinctive that (German ethologist Irenaus) Eibl-Eibesfeldt was convinced it is innate, a human female courtship ploy that evolved eons ago to signal sexual interest.
Men -- and women -- are attracted to people who are as attractive as they are.
'If you go for someone roughly equally to you in attractiveness, it avoids two things,' Nottingham Trent University psychologist Dr. Mark Sergeant tells the Telegraph.
'If they are much better-looking than you, you are worried about them going off and having affairs,' he says. 'If they are much less attractive, you are worried that you could do better.'
In 1969, University of North Carolina sociologist Glen Elder found that looks and wealth tend to find one another -- namely, good-looking women tended to settle down with less attractive, but wealthier, men.
Since then, it's become a multiple-times confirmed finding in the social sciences.
Most recently, a 2010 study found that men pictured with a Silver Bentley Continental GT were way more attractive than those pictures with a Red Ford Fiesta ST, and a 2014 study found that men pictured in luxury apartment were more attractive than those in a control group.
Why the attraction to resources? Evolutionary psychologists say it's because women want a mate who can provide for them.
Psychologists call it the 'George Clooney Effect.'
As a 2010 study of 3,770 people showed, women often prefer older men. As they become more financially independent, they like older guys even more.
'We think this suggests greater financial independence gives women more confidence in partner choices, and attracts them to powerful, attractive older men,' lead author and University of Dundee psychologist Fhionna Moore said in a statement.
Evolutionary psychologists say that younger women and older men often pair up because while fertility only lasts from puberty to menopause in women, it starts at puberty and can extend long into midlife for many men -- and they have a greater opportunity to accumulate status and resources.
While some claim that the beard trend is over, the research says it's not.
According to a 2013 Australian study, the most attractive beard length is 'heavy stubble,' which comes after about 10 days of growth.
'Facial hair correlates not only with maturity and masculinity, but also with dominance and aggression,' write authors Barnaby J. Dixson and Robert C. Brooks.
'An intermediate level of beardedness is most attractive,' they added.
It only takes a bit of maintenance to keep that 10-day beard all the time.
A 2007 University of California -- Los Angeles study found that women are more likely to have short-term relationships with guys who have big muscles.
The evolutionary signal at work here?
Sexual characteristics like muscularity are 'cues of genes that increase offspring viability or reproductive success,' say authors David A. Frederick and Martie G. Haselton.
But Frederick and Haselton took away another telling finding: less-muscular men were thought to be a better fit for long-term relationships.
One of the most robust findings in psychology is the halo effect, a bias where you unconsciously take one aspect of somebody as a proxy for their overall character. It's why we think beautiful people are good at their jobs, even when they aren't.
But as Scott Barry Kaufman notes at Greater Good, the halo effect works in other ways, too.
A 2014 Chinese study found that people who had positive personality traits -- like kindness and honesty -- were rated as more attractive than those with negative personality traits -- like being evil or mean.
'Even though beauty is an assessment of fitness value, there is no reason why assessment of fitness needs to be purely physical,' Kaufman writes, meaning that being kind makes you look like you'd be a stable, worthwhile mate.
Contrary to the 1950s ideal of the aloof breadwinner, women are into men who can talk about their feelings.
'When men are vulnerable women find them more desirable both emotionally and sexually,' says psychologist and life coach Lisa Kaplin.
'Being vulnerable will not hurt men's masculinity: just the opposite,' she continues. 'Emotionally well-rounded men are more desirable to more women and are ultimately likely to be emotionally stable and better long-term partners than men who are closed up and unwilling to share intimate parts of their lives.'
A 2010 cross cultural study -- with participants from China, England, Germany, and the US -- found that women are most attracted to men wearing red.
It's been a symbol of status since at least the Roman times, when the most powerful men were called coccinati, the ones who wear red.
Red works for women, too.