The more sex a woman has with her partner, the less attracted she is to other men. That’s the upshot of a study by medical psychologists Ursula Hess, Stuart Brody, and their colleagues, who asked female subjects to report the details of their sex lives and rate the facial attractiveness of twenty-four men. Sexually sated women gave hot guys significantly lower ratings than did women who weren’t having as much sex. Simply put: the more sex women recently had with their partners, the less attracted they were to hunky alternatives. It’s as if biology blinds them to other opportunities.

Several factors may be at play here — and hormones are implicated. As I describe in BLONDES, the hormone prolactin, released after orgasm, makes a person feel sated, at least for awhile (two days, according to some studies, and up to a week according to others). The hormone oxytocin — released when touching, caressing, kissing, and orgasming — makes a woman feel more attached to and trusting of her current partner, even if he’s just a fling (the study didn’t measure relationship strength). Naturally, the more attached a woman feels, the less likely she’ll be on the lookout for another beau. Or it just might be love. A separate study led by evolutionary psychologist John Maner also found that women (and men) in love are automatically less likely to pay attention to the faces of good-looking strangers.

(Of course the whole phenomenon could be a virtuous cycle: the more committed, the more sex — and the more sex, the more committed.)

As a separate and interesting side note, researchers in the sex study also found that depressed women — even those with partners — masturbate more, which the researchers think may either be self-soothing or actually exacerbate depressive symptoms. That, or it just might be that these women are down because they haven’t found the right partners. Perhaps they’ve blinded themselves to other opportunities.

I’d like to know if the same is true for men.