Science Says We Like When People Flirt With Our Partner — Up Until This Point

There’s a social phenomenon that psychology professor Gurit Birnbaum often sees play out among people she knows and couples in the wild: Thinking they’re sly, one partner will try to make the other jealous or get a rise out of them by flirting or seeking attention elsewhere.
“It made me wonder: Does this strategy actually work? Does it make the partner feel more desired, or does it prove counterproductive and damage the relationship?” she told HuffPost.
With her interest piqued, she and her research team at Reichman University in Herzliya, Israel, teamed up with researchers at the University of Rochester in New York to explore that very premise. A new study published in the Journal of Sex Research reveals their findings.
“Prior research suggests that seeing someone flirt with our partners is actually a positive thing, up to a certain point.”
The study revealed a surprising twist in the way we respond to others’ interest in our partners: At first we kind of like it, but that enthusiasm is short-lived. Once we’re coupled up and in a relationship, seeing someone flirt with our partner causes a dip in both our desire for them and our desire to invest further in the relationship.
“Both men and women displayed similar defensive behaviors, including decreased desire for their partner, reduced investment in the relationship and increased vigilance towards potential rivals,” Birnbaum said.
Prior research suggests that seeing someone flirt with our partners is actually a positive thing, up to a certain point. That’s because as social animals, we rely on social cues to help us search out a desirable partner. One specific cue, known as mate choice copying, occurs in humans and other animals: Seeing others interested in a potential mate makes that person appear all the more attractive and in-demand. Consider it the “I’ll have what she’s having” approach to dating.
“Or imagine you’re at a party,” Birnbaum said. “You might notice someone who seems attractive, but you’re not sure about their personality or if they’d be a good partner. That’s where mate choice copying comes in.” That outside interest convinces you that the person is worth your time, too.
Another example of mate choice copying, according to Birnbaum? Research has shown that women tend to perceive men as more desirable if they’re photographed in the company of other women (especially smiling women), as opposed to photos of guys alone or in the company of other men. (Do with that information what you will, dudes on dating apps.)
And she said men and women both are more likely to judge a potential mate favorably if they see that the person’s exes were attractive.
We use this to make snap judgments about relationship building because other desirable traits ― how trustworthy a partner is, for instance, or how loyal they are ― aren’t as easily observable.
“By noticing who others are interested in, we get a shortcut to figuring out who might be a good partner, minimizing the time, energy and potential risk involved in finding a compatible partner,” the professor said.
Once we’ve established a relationship, though, mate choice copying gives way to fears of mate poaching: In evolutionary psychology, mate poaching occurs when someone tries to form a romantic or sexual relationship with a person who is already in a romantic relationship with someone else. It could be just a one-time hookup that the poacher’s after, or it may be a long-term relationship.
Every generation seems to have a celebrity example of mate poaching that strikes fear in them: There’s the classic case of Elizabeth Taylor poaching good friend Debbie Reynolds’ husband Eddie Fisher. Or Angelina Jolie allegedly getting together with co-star Brad Pitt on the set of “Mr. and Mrs. Smith” when he was married to Jennifer Aniston.
“What’s interesting is that research on mate poaching reveals that even being the recipient of unwanted flirtation can introduce doubt into a relationship, potentially weakening the bond between partners,” Birnbaum said.
Study methodology is usually a pretty staid business, but this one’s pretty juicy: In three experiments, 244 participants (126 women, 118 men, all heterosexual) were asked to imagine a situation in which another person flirted with their partner (the external attention condition) or had a neutral interaction with another person (control condition).
After each experiment, participants then rated their sexual desire for their partner, their interest in engaging in relationship-maintaining efforts (things like finishing a chore for a partner or deterring rivals who hit on their partner).
The most interesting of the three experiments involved virtual reality: Using VR technology, Birnbaum’s team created a safe environment ― no one was going to get punched for putting the move on someone’s partner on their watch ― to study the all-too-real emotions of jealousy and possessiveness. Using a VR device, participants observed a virtual stranger interacting with their partner at a bustling bar. The virtual stranger either displayed interest in their partner or behaved neutrally.
The VR experiment found that any sort of flirting was bad for the relationships. People reacted to unsolicited attention given to their partner by feeling less desire for their partner, showing reduced interest in investing in the relationship, and becoming more interested in thwarting the flirtatious stranger. (They’d say things to devalue the other woman or man’s attractiveness or otherwise belittle them.)
“By creating emotional distance and withdrawing investment, we found that both men and women aim to minimize potential pain and hurt if their fears of losing their partners to others materialize,” Birnbaum said.
There are a few limitations to the study worth noting: For one, it included only heterosexual, monogamous couples ― no LGBTQ pairs. And it’s possible, Birnbaum said, that the results would vary depending on relationship phase (for example, newly dating versus has been married for years), the rival’s connection to the couple (a stranger or a close friend) and the type of relationship people have (such as open versus monogamous).
For instance, many polyamorous couples in open relationships speak positively of their experiences with compersion: the feeling of joy when they see their partner’s joy, even if it does not involve or directly benefit them. So, instead of feeling jealousy or insecurity when a person flirts with their spouse at a bar, they may feel excited for them.
Given the variety of monogamous-ish and non-monogamous relationships out there these days, “there’s a lot of promising avenues for future research with a subject like this,“ Birnbaum said.
The big takeaway is that generally it’s a bad idea to make your partner jealous by seeking attention elsewhere.
“While it might seem like a way to feel more desired or secure, our research shows this behavior often backfires,” Birnbaum said. “Instead of making your relationship stronger, it can damage the very connection it aims to enhance.”
And if you find yourself in a situation in which someone expresses interest in your partner, recognize that you might get a little self-protective and not be as cool-headed as you’d like to be. If they’re not flirting back, you have nothing to worry about. Just knowing that it might irk you and then quieting those feelings of relationship uncertainty could make a difference.
“This awareness can help prevent escalation, minimize potentially hurtful reactions and promote open communication within the relationship,” Birnbaum said.