The 1980s Hollywood film When Harry Met Sally posed the age-old question: "Can Men and Women Be Friends?" The dynamic of opposite-sex friendships has been explored in TV, film, and science; the pendulum has swung back and forth on whether guy-girl friendships work, or whether friends really do make the best lovers. Researchers at the University of Wisconsin-Eau Claire suggest it all depends on who you ask in the friendship.

”We conclude that men’s and women’s everyday experiences with opposite-sex friends differ from their mental conceptions of opposite-sex friends" wrote the researchers.

The study, published in Evolutionary Psychological Science, found men and women view opposite-sex friends differently. In particular, men were more likely than women to report being attracted to their opposite-sex friends, but the difference is not substantial. So, why does this discrepancy exist?

Lead author April Bleske-Rechek and her colleagues conducted a series of studies to evaluate if men report much more physical attraction to their friend than women by recruiting undergrads.

In the first experiment, researchers looked at 40 pairs of opposite-sex friends who were approached while they were eating or sitting together at a university student union during lunch to participate in the study. The students separately answered a few questions, including ratings of their own and their opposite-sex friend’s attractiveness and personality using a seven-point scale (not at all to moderately to extremely). At the end of the questionnaire, students reported their relationship status: “We are just friends,” “We are in a romantic relationship,” or “Other.” The researchers found the average level of physical attraction for both genders was low to moderate, not indicating men were strongly more attracted to their opposite-sex friend than women.

Bleske-Rechek and her colleagues wondered what would happen if they asked participants to tell them about an opposite-sex friend versus approaching two opposite-sex friends in their natural habitat.

“Are the members of the opposite sex with whom young adults pass their time in an everyday context different from the members of the opposite sex that they visualize when researchers ask about their friends?”

Before testing the new hypothesis, the researchers did another round of questions with 32 friend pairs at the university, but once again the results were the same as the previous study.

In the third experiment, a total of 114 men and 192 women were recruited through research pools and online social networks. They were asked to fill in the name of an opposite-sex friend, so the researchers knew the specific person they were thinking of via a computer program. The participants were asked: “Which of the following describes the person who has come to mind?” and had to check one or both of the following answers: “A person of the opposite sex who is a friend” and “A person of the opposite sex who I am physically attracted to.” At the end, participants reported their sex, current romantic relationship status, age, and sexual orientation.

The findings revealed men were less likely to say that person was a friend, and more likely to say that person was someone they were attracted to, or a friend that they were also attracted to. Among those involved in a romantic relationship, fewer men than women characterized the person as both a friend and someone they were attracted to, however, none of the participants in romantic relationships said they were just friends because they were attracted to them.

The researchers concluded both sexes varied widely in their level of attraction toward the friend they were approached compared to when asked to think about a friend of the opposite sex.

“When looking for friends of any gender, we tend to gravitate towards others with similar characteristics and interests of our own. Commonality and chemistry between individuals is important when developing friendships,” Dr. Ildiko Tabori, a clinical psychologist in Los Angeles, previously told Medical Daily.

A 2000 study published in the Journal of Social and Personal Relationships found friendship attraction, or connection devoid of lust, does exist. Bonds between men and women are changing, with both men and women in cross-sex friendships more often seeing each other as friends or confidants rather than romantic interests. Participants who reported no physical or sexual attraction to their friend were in significantly longer friendships compared to those who felt an attraction.

Research on the dynamic of opposite-sex friendships suggests the definition of friendship is subjective. Men may be more likely than women to think of their opposite-sex friend as physically attractive and sexually desirable, but this could just be an evolutionary trait. Researchers believe our hardwired mating instincts have an effect on whether we can truly be just friends with anyone of the opposite sex. Instinctually, men tend to report more attraction to their female friends than women to males because men faced the risk of being shut out, genetically, if they didn’t take “advantage of various reproductive opportunities,” according to lead researcher April Bleske-Rechek.

If you’re feeling sexual tension between you and your friend, you need to set limits and maintain appropriate boundaries.

It’s all about whether you value your friendship over a night of lusty sex.

Source: Bleske-Rechek A, Joseph WE, Williquette H et al. Sex Differences in Young Adults’ Attraction to Opposite-Sex Friends: Natural Sampling versus Mental Concepts. Evolutionary Psychological Science. 2016.