Scientists at the University of Delaware focused on sexual jealousy. They rounded up heterosexual couples, and asked the man to rate the attractiveness of women while their female partners were instructed to point out targets amid a series of sometimes-disturbing images. The women who felt the most jealous about their boyfriends rating other women were the worst in identifying targets, suggesting they suffered from "emotion-induced blindness." The researchers haven't yet tried to make men jealous — I'd predict similar results — but their findings are no surprise. It's a lucky person — or an extremely evolved one — who hasn't at one point or another felt jealousy taking over all other cognition. And it's not always jealousy over a partner's wandering eye, either.

Some of the most potent jealousy I felt in my life has had nothing to do with sex. I've felt jealous of other women who seemed like they had it all together, like they never worried about anything, or like they were effortlessly cool. And while I'm not sure this jealousy would have blinded me to actual visual stimuli, it did prevent me from seeing something perhaps more important: that few people lead the kind of anxiety-free lives I imagine for people I've envied. Jealousy can blind you to your own strengths but also to other people's difficulties, making you a less empathetic person — which is one reason I'm trying to eliminate it from my life, even if it doesn't make me any better at target practice.