Men in long-term relationships tend to underestimate their female partners’ sex drive, new data from two Canadian universities show. A study published last month in the Journal of Personality and Social Psychology indicates that the conventional wisdom eternally exploited in sitcom riffs and stand-up routines—that wives are incapable of satisfying their husbands’ gargantuan libidos—may be a figment of the male imagination.

Psychologists from the University of Toronto and the University of Western Ontario studied 229 North American couples, most of which were heterosexual partnerships. (A few same-gender couples participated, but not enough to produce any statistically significant data.) Research subjects were aged 18 to 68 and had been in their current relationships for an average of six years; they reported having sex about one to two times per week. The members of the couples either visited the lab once to report on their general sexual desire, their perception of their partner’s sexual desire, and their satisfaction with their relationship, or kept a daily three-week diary on those same three factors. Some also reported on their daily level of motivation to evade sexual rejection.

The researchers found that, on a regular basis, men significantly underperceived the degree of their female partners’ sexual desire, while women consistently made accurate judgments about how much their male partners wanted sex. Among diary-keeping couples, on days when men underestimated their female partners’ libido, the women showed higher levels of relationship satisfaction.

This suggests that, whether consciously or not, men might be better partners when they think they have to work for it—in other words, a man will try harder to please his female partner if he thinks she’s not responding to his advances, which keeps him from taking the relationship for granted and getting lazy. Another likely explanation for male sexual underperception: fear of rejection. On days when men reported in their diaries a high level of motivation to avoid sexual rejection, they were more likely to underestimate their partners’ desire for sex, perhaps as a precaution against making advances that could go unreturned.

Socialized beliefs and behaviors could contribute to the perception gap, too. Women may make fewer or subtler sexual overtures that their partners, or, Elizabeth Bernstein suggests at the Wall Street Journal, if a woman knows she has a higher sex drive than her husband in general or on a particular occasion, she may refrain from making a move to avoid embarrassing or emasculating him if he wants to say no.

But there’s a larger, more amorphous barrier to accurate male sex predictions out there: The prevailing notion that women just aren’t that concerned with sex. As Taryn Hillin writes at Fusion:

These framings ignore the fact that women also read news reports and probably already know that all those sitcom gags about sexually uninterested wives don’t match up with the reality of their experiences. As a lump demographic, men report higher sex drives than women, but women’s reports cover a much larger range that varies based on geography and other environmental factors, suggesting that the concept of sex drive is molded by sociocultural forces. Kristen Mark’s June 2015 paper in Current Sexual Health Reports analyzed 31 studies on sexual desire and sex-drive discrepancy in relationships; she found that, in long-term heterosexual partnerships, women and men are equally likely to be the lower-libido member of their couple.

Still, the findings of this new Canadian study were somewhat surprising, because the only previous research on men’s sex-drive perception focused on the situation of a man meeting a woman for the first time or evaluating the sexual interest of a fictional or unknown woman. These studies have reliably shown that men tend to overestimate the sexual interest demonstrated by these women’s behaviors. That explains the circumstances of most overaggressive late-night bar encounters. Taken together, these contradicting trends suggest that when many men try to gauge a partner or potential partner’s desire, they perceive what they want to believe.