SSS 2008-06-16（在线收听）

This is Scientific American's 60-Second Science, I'm Karen Hopkin. This'll just take a minute.

You've landed a small role in a low-budget horror movie.To get ready,you need to practice your reaction shot, you know, that look you will get when your boss peels off his face to reveal the slime-oozing alien he really is. So look in the mirror and give us some terror.If you're doing it right,your eyes are wide-open and your eyebrows are raised,but why is that? I mean how come people when they're scared all make a similar face.Darwin thought there was a reason that all expressions evolved because they offer some benefit,and scientist from Ontario think Darwin was right.They asked volunteers to try to look frightened and then they measured the physiological effects.They found that making a fraidy face allows people to see further,locate targets faster and take in more air when they breathe. The findings appear in the current online issue of Nature NeuroScience.Those reactions make sense because if you see something startling or out of the ordinary, you can use your fear-enhanced vision to assess the situation and if need be,take a deep, fear-boosted breath and run.

Thanks for the minute for Scientific American's 60-Second Science, I'm Karen Hopkin.