The Science of Romance: Why We Flirt

That smile! That glance! That rapt attention! We flirt even when we don't need to. And that can be good

Laura Kleinhenz for TIME

Open Body Position: This come-and-get-me stance suggests the man is neither about to flee nor fight

Contrary to widespread belief, only two very specific types of people flirt: those who are single and those who are married. Single people flirt because, well, they're single and therefore nobody is really contractually obliged to talk to them, sleep with them or scratch that difficult-to-reach part of the back. But married people, they're a tougher puzzle. They've found themselves a suitable--maybe even superior--mate, had a bit of productive fun with the old gametes and ensured that at least some of their genes are carried into the next generation. They've done their duty, evolutionarily speaking. Their genome will survive. Yay them....