SSS 2009-06-23（在线收听）

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

If all you have is a hammer, they say that everything looks like a nail. But when you use that hammer, it looks like you are arm to your brain anyway. A report in the June 23rd issue of the journal Current Biology shows that the brain interprets tools as just an extension of your physical self. To move our bodies around in space, the brain builds what's called a “body schema”, a representation of all of our various parts. And this so-called schema is frequently updated to keep up with our ever-changing bodies. Otherwise you will think you were still a bitty baby. Now scientists have taken this body image overhaul a step further. They've shown that when we use a tool, even for a few minutes, the brain sees it as a temporary body part. Subjects were asked to pick up a block. They then used a long mechanical grabber to pick up the same block. Then they tried to snag the block bare-handed again. And it took longer than their initial grab. That's because they were briefly behaving like their arms were still augmented. So next time you feel like a total tool, you might just be hitting the nail on the head.

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