University of Aberdeen? I'm surprised they weren't studying sheep......
It's not really surprising; sexual selection dictates that men compete for female approval, so it's natural that we'd (well, men) be built to look negatively upon competition. On the other hand, females excercise mate choice, so they'll judge the best male through things such as a 'social' standing; it's also perhaps linked to the mildly polygamous nature of humanity (males with some - not many - female mates, as evidenced by sexual dimorphism).
(EDIT; I'd suspect the mechanics of attraction are deep wired enough not to be affected, but I can't help but wonder if they did a similar experiment with homosexual attraction)