So what's going on here? Is intelligence attractive to guys or not? Do smart girls give off some kind of offensive pheromone? Are boys just stupid?
No. Well, yes, they are, but in a way that requires further elaboration.
The big surprise finding here—especially surprising because the researchers didn't bother mentioning it until halfway through the paper—is that the experiments also tracked the guys' self-reported feelings of masculinity, and these took a nosedive when the woman who outperformed them was actually in the room. The guys felt so emasculated by this that they actually moved their chairs further away from the offendingly smart woman. (This only happened when she was physically present; the guys' masculinity ratings actually went up, for reasons passing understanding, when they were outperformed by a hypothetical or absent woman.)
So the real takeaway here, if you're a smart girl, is not that guys will forever be scooching their chairs further and further way from you as though you smell like a foot. The takeaway is just that guys don't like feeling inferior in front of you, which probably is something you already knew. If you don't believe me, go get a basketball and dunk on a guy and then showboat around and make fun of his mom. He won't go on any dates with you at all.