After my post about people’s fondness for other people’s partners, (“Do Single Women Seek Attached Men?”), more than 300 Lab readers weighed in with their anecdotes and theories. Now here’s some more guidance from the expert who coined the term for this practice: mate poaching.

David Buss, a professor of psychology at the University of Texas at Austin, is the author of many books, including the “Evolution of Desire,” the 1994 book that introduced the term “mate poaching,” and the forthcoming “Why Women Have Sex,” co-written with Cindy Meston. His paper with Dr. Meston about the 237 reasons for having sex inspired a most lively discussion here at the Lab last year.

Dr. Buss told me that he tried to come up with a less pejorative term than “mate poaching” but wasn’t able to find one. Here’s his reaction to the debate that’s been going on at the Lab, along with some findings about men who poach:

John Tierney’s piece on mate poaching clearly struck a powerful chord, evoking an amazing array of excellent insights and personal experiences. As someone who has published on the topic in articles and in books, I thought I’d add my two cents to the discussion. A couple important distinctions are worth introducing. The first is the distinction between poaching for short-term sexual encounters versus poaching for more committed mateships. The first scientific study of mate poaching (Schmitt & Buss, 2001) found that substantially more men (60%) than women (38%) admitted to having attempted to poach an already mated person for a sexual encounter. The sex difference was smaller for long-term mate poaching, but still present—60% of the men and 53% of the women. Similar sex differences have been discovered in the most massive cross-cultural study of mate poaching ever conducted [by my colleague David Schmitt], which involved 16,954 participants from 53 different countries. So although the study reported by Tierney highlighted the interesting finding for single women, available evidence suggests that men are more likely than women to mate poach, or more likely to admit to it, a sex difference especially pronounced for sexual liaisons. Abhorrent though it may be judged, mate poaching is clearly one strategy in the arsenal of human mating strategies. And given the reputational damage a mate poacher can incur, its prevalence is undoubtedly underreported. Many don’t interpret their actions as “mate poaching.” Some just think “we fell in love with each other” or “we were just acting on our mutual sexual attraction” or “he wanted to leave her anyway.” The nature of the human mating system matters. Although we have a presumptively monogamous mating system, it’s not “effectively” monogamous. Rarely do modern humans mate with one and only one person for their entire lifespan. Premarital mateships, mate switching, and divorce are all common, as are affairs. Nor was total monogamy characteristic of most human cultures across the globe. The cross-cultural record reveals that 83% of cultures practiced some form of polygyny (one male with two or more wives). In these cultures, single women are often attracted to mated men, and it’s often not considered mate poaching. Single women in these cultures typically find mated men with high status, resources, and a wife or two more attractive than single men who lack the status or desirability to attract a mate. Women’s sexual psychology evolved in the context of a mating system with some polygyny. Modern women have inherited the sexual psychology of their successful ancestral mothers. They carry with them an attraction for men who have demonstrated an ability to attract other women. Mate poachers use an array of tactics to implement their strategy, ranging from derogating the partner (e.g., “She’s not good enough for you; you deserve someone who treats you better . . . like me”) to showcasing desirable qualities that the current mate lacks. Some mate poachers just want sex. Some want commitment. And some use a “bait-and-switch” tactic of seeming to offer costless sex, and then becoming more emotionally enmeshed until the man wakes up one day and realizes that he can’t live without her. We may not like the tactics, but sometimes they work and sometimes they end up in successful unions. Angelina Jolie and Brad Pitt seem to have a pretty good relationship.

I welcome your reactions to Dr. Buss’s observations. Angelina and Brad are both invited to comment either about the theory of mate poaching or about their own experiences — including the perpetual (and so far baseless) rumors that their relationship is on the rocks.

(One note about the male-female differences in mate poaching. In my previous post, I cited a study at Oklahoma State University that found single women showed special interest in men who were already romantically involved with someone else. Those findings don’t necessarily contradict the results cited by Dr. Buss.

(Like Dr. Buss, the Oklahoma State researchers found that men were more likely than women to be interested in pursuing someone who was already attached. But the men in the Oklahoma State study were also more likely than the women to be interested in pursuing someone who wasn’t attached. The guys were more interested than the women in pursuing any partners. It didn’t make a significant difference to the men in the study, or to the women in the study who were already in relationships, whether a potential partner was already attached to someone else. But the potential partner’s romantic status did make a significant difference to the single women in the study, because they were more likely to be interested in a man if he was attached than if he wasn’t.)