Men who financially provide for female friends are more likely to view those friendships as mating opportunities

Men who were more romantically or sexually interested in their female friends tended to pay for more shared expenses, and women read this behavior as a sign of mating interest, according to research published in Evolution & Human Behavior.

Cross-sex friendships are often described as “just friends” relationships, but they can involve attraction, romantic possibility, or sexual interest. Many people report experiencing attraction within cross-sex friendships, and many romantic relationships begin as friendships. This raises an important question: if mating interest sometimes exists within friendships, how is that interest expressed or detected?

Ryan T. Dobson and colleagues examined whether financial provisioning, such as paying for more of a shared bill, might operate as a courtship behavior in cross-sex friendships. Their work was guided by theories suggesting that men, more than women, may use displays of resources or generosity to signal romantic or sexual interest, partly because women have historically placed greater importance on a partner’s willingness and ability to invest resources. The researchers also tested an alternative explanation: perhaps financial provisioning reflects how valuable or high-quality people perceive the friendship to be, rather than mating interest.

This research included 581 undergraduate students from a southwestern university in the United States. Participants completed an anonymous online survey during the spring 2024, fall 2024, and spring 2025 semesters. Participants who failed data-quality checks or reported being asexual or homosexual were excluded from analyses given the study focused on heterosexual cross-sex friendship dynamics. The final sample was mostly female, with an average age of 21.3 years.

Participants answered questions about their closest and second-closest cross-sex friends, excluding current romantic partners and family members. They completed an 11-item measure of their own romantic and sexual interest in each friend, a three-item measure of how much they thought each friend was interested in them, a bill-paying item using a 1-to-7 scale where higher scores meant the participant paid more, and an eight-item friendship-quality measure using a 1-to-7 agreement scale.

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Because participants reported on two friends, the researchers could test both between-person effects, such as whether some men generally pay more across friendships, and within-person effects, such as whether a man pays more for the specific female friend he is more attracted to.

Dobson and colleagues found that men and women both reported a sex-differentiated pattern in bill paying. Men said they paid for more of the bill with female friends, and women said their male friends paid for more of the bill with them. This replicated earlier work suggesting that financial provisioning is more common from men toward women in cross-sex friendships.

The key findings supported the idea that financial provisioning can function as a courtship cue in friendship. Men who reported greater overall mating interest in their female friends also reported paying for more of the bill. This pattern did not appear among women in the same way; women’s mating interest did not predict greater financial provisioning, and women who were more interested in their male friends actually reported paying less.

Friendship quality also did not predict financial provisioning. Participants who viewed a cross-sex friendship as more supportive, enjoyable, emotionally close, valuable, or difficult to replace were not more likely to pay a larger share of expenses, providing no support for the alternative hypothesis.

Women also seemed to interpret men’s financial provisioning as a sign of interest. Women whose male friends paid more of the bill perceived those male friends as more interested in mating with them. Men, however, did not show the same pattern when female friends paid more.

Importantly, the effects were mainly between-person rather than within-person: the findings did not show that the same man pays more for the particular female friend he likes most. Instead, some men were more inclined than others to view cross-sex friendships as mating opportunities and to pay more across those friendships.

Of note is that this study was cross-sectional and relied on self-report, so it cannot prove that men intentionally paid more to signal mating interest or that women inferred interest because of the payment behavior. The sample involved young adults from a university setting, so the findings may not generalize to older adults or to different cultural contexts.

Overall, the findings suggest that cross-sex friendships are not equally platonic for everyone and that financial generosity may be one way mating interest is expressed and perceived within some male-female friendships.

The research, “Courtship in cross-sex friendship: novel tests of male financial provisioning as a signal and cue of mating interest,” was authored by Ryan T. Dobson, William Costello, and David M.G. Lewis.