The recent research article by Rodeheffer et al. (2016) on Evolutionary Psychology begins with a true story of Meredith. Meredith is an attractive lady who worked for $50 an hour for spending time with wealthy men. She is neither a prostitute nor escort, but she works as a wing woman for a New York based company, which provides service for men who want to spend time with wing women. The main goal of hiring an attractive young wing woman is not to spend time with her, but to ultimately make themselves look good to other women, whom men hope to eventually spend the night with.

This human behavior is related to a biological concept called female mate choice copying: females prefer to choose the male as a mate when the male is seen having romantic or sexual access to another female (Pruett-Jones, 1992). I call female mate choice copying “The Girlfriend Effect.” In guppies, the effect is so strong that it can countermand inherent mate preference. For example, female guppies often prefer males with brighter colorations to dingy male guppies, but the same female will give up bright colored males for dingy ones when dingy ones were observed to be mated with other females (Dugatkin, 1992).

Don’t get me wrong, the male mate choice copying also occurs in some species, including humans Place et al. 2010). However, I think that this phenomenon would be attenuated in males because natural selection in many species would select males who are less discriminate in choosing mates and “punish” males who mate-choice-copy (hence weeding them out from population over time). Darwinian sex-roles (males being less discriminate in mates and females being choosier in mates) have been confirmed across the animal kingdom (Janicke et al., 2016).  Plus, if males prefer females that have already mated with other males, the situation would get more complicated. Males have lower paternal assurance; they would also be challenged by other males who might mate guard their mates (i.e. sticking around females and preventing other males against sexual access to females). Therefore, male mate choice copying is more complicated than female mate choice.

Place et al. (2010) study asked participants to rate how attractive, desirable, and interested in dating with the opposite sex target in the photo. They were asked to rate the person for short term and long term relationship context. Then, the participants saw 10 seconds of real-life speed dating interactions in which the opposite sex target was the date. The sessions showed either positive interactions or negative interactions. Participants were told that all videos showed either mutual interest or mutual disinterest. After watching the videos, they rated the opposite sex target again on various traits. The results revealed that mate choice copying was stronger in females. The study analyzed if there were changes in ratings on the target photos before participants saw the dating videos and after they saw the dating sessions.
                                                                                         Figure adapted from Place et al. (2010)


Female participants decreased their ratings on the target for both short-term and long-term relationship after they saw the speed dating interaction with no perceived interest. If the speed-dating is perceived as successful and interesting, female ratings on the male target increased in both short-term and long-term. For male participants, the ratings on female target went up in both short-term and long-term relationships after seeing the speed-dating video. It does not matter if there is no perceived interest in the video. Males still increased their ratings on female target. But the male mate choice copying, which I call it the boyfriend effect, seems to be stronger in long-term relationship. From natural selection view point, males are expected to be less discriminate in mates. Now lets’ get back to Rodeheffer et al. (2016)’s article which examined female mate choice copying.

First things first: so, what evolutionary benefits do mate choice copying confer? Rodeheffer et al. (2016) provided 3 reasons: (1) the preferred males by other females decrease the time and energy to find the mate (These could be focused on other life activities) (2) reduces the predation problems (You could get killed while looking for prince charming) (3) reduces the poor mate choice decisions (You might make a terrible partner choice). Female mate copying is documented in various animal species such as the guppy, the sage grouse, the Japanese quail and in humans (Rodeheffer et al., 2016).

In study 1, Rodeheffer et al. (2016) manipulated the target photos in which men who were of average attractiveness were paired with higher than average attractive females. These target photos were given to female participants who rated the male on desirability as a romantic partner, attractiveness, and romantic appeal. The study also manipulated the relationship condition of the target photos. Female participants were told that the girls next to the man in the target photo is either his girlfriend, adopted sister, cousin or ex-girlfriend.The figure adapted from Rodeheffer et al. (2016)  Screen Shot 2016-07-23 at 9.34.34 AMThe results revealed that guys were rated higher on desirability scores in girlfriend condition, but not in adopted sister, cousin or ex-girlfriend conditions.

Figure adapted from Rodeheffer et al. (2016) 

In study 2, Rodeheffer et al. (2016) showed the male photo in alone picture or in paired picture with the attractive girl (i.e. the same target photos of study 1) to female participants. In both alone and paired conditions, female participants then rated the qualities of the person on various characteristics such as intelligence, trustworthiness, humor, wealth, romance, etc.

As expected, girlfriend effect was still there. The males paired with the attractive females were rated higher on various mate qualities than when the same male was presented alone. The statistical analysis called mediation analysis in study 2 revealed that women’s psychological thoughts on the mate qualities in study 2 mediated between conditions (alone vs. paired) and the ratings of partner desirability in the photo. In other words, the thought is the driving psychological mechanism behind the girlfriend effect. That is the girlfriend effect becomes diminished when women thought men did not have high qualities on aforementioned traits (intelligence, trustworthiness, humor, wealth, romance, etc.)

There are still unanswered questions. If you think about it, the Girlfriend Effect, according to this study, works when the attractive female is paired as the girlfriend, but not as adopted sister, cousin or ex-girlfriend (study 1). So the question you might be asking is how does the New York-based wing woman work? What if the attractive wing-girl is seen as the adopted sister, cousin or ex-girlfriend? It would probably backfire and have unintended consequences. Or maybe a wing woman is seen as a friend. Friend conditions, such as best friends, close friends, colleagues, were not tested in study 1. In real life, the woman could be perceived as friends. And, what if the other women would see the man with the wing woman as already taken? Perhaps, the optimal solution is to have wing women seen by other females as flirting with males.

I think humans, unlike animals, can and do think too much. Perhaps, mate choice copying is less subtle than it is. May be not. Think about how the boyfriend or girlfriend effect applies to these familiar situations. Think about a popular girl or boy at your high school. They keep being popular. Think about a college crush. He or she looks even more appealing and desirable when you find out that your rival was showing interest in your crush. Great, now you are aware of mate choice copying in humans. Make a mindful choice in your partner. Don’t get fooled by the boyfriend effect or the girlfriend effect.


Rodeheffer, C. D., Proffitt Leyva, R. P., & Hill, S. E. (2016). Attractive female romantic partners provide a proxy for unobservable male qualities: The when and why behind human female mate choice copying. Evolutionary Psychology,1-8.

Dugatkin, L. A. (1992). Sexual selection and imitation: Females copy the mate choice of others. American Naturalist, 139, 1384–1389.

Janicke, T., Häderer, I. K., Lajeunesse, M. J., & Anthes, N. Darwinian sex roles confirmed across the animal kingdom. Evolutionary Biology, 2(2).

Place, S. S., Todd, P. M., Penke, L., & Asendorpf, J. B. (2010). Humans show mate copying after observing real mate choices. Evolution and Human Behavior, 31(5), 320-325.doi:10.1016/j.evolhumbehav.2010.02.001

Pruett-Jones, S. (1992). Independent versus non-independent mate- choice: Do females copy each other? American Naturalist, 140, 1000–1009.

Thanks to Leah for helping me with the edit on the article 🙂


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