It turns out the best looking thing on a man may be a good-looking woman.

Researchers report that women find a man they see with an attractive woman more desirable than unattached men. That’s according to a study in the journal Evolutionary Psychology. [Christopher D. Rodeheffer, Randi P. Proffitt Leyva and Sarah E. Hill, Attractive Female Romantic Partners Provide a Proxy for Unobservable Male Qualities: The When and Why Behind Human Female Mate Choice Copying]

Researchers had two groups of female college students rate photos of men—all of whom had first been rated as being of average attractiveness. The first group of 148 women was shown pictures of those men with an attractive female. The subjects were told that the women in the photos were either a girlfriend, ex-girlfriend, cousin or adopted sister. And the subjects rated the men with the girlfriends as more desirable than the men shown with partners described as being exes or relatives.

The second study group of 97 students were shown average looking men with an attractive woman who was described as definitely a girlfriend. And again the women rated the men with the good-looking gals as more desirable than the single guys. Plus, the attached men were thought more likely to be more intelligent, trustworthy, humorous, wealthy and attentive.

Researchers deduced that the women probably assume partnered-up men must have those qualities of smarts and personality to be an appropriate match for a good-looking mate.

So, turns out that what many of us always suspected may be true—men look better when they’re a proven commodity.