SSS 2010-10-20（在线收听）

You're trying to exercise willpower—to avoid eating that second piece of cake or buying an electronic toy you don't really need. Try firming up your muscles. Any muscles. Now you can walk away—as long as walking away is truly in line with your overall goals.

Researchers created various tests of discipline. In one test, participants got a so-called health tonic of diluted, but unpleasant tasting vinegar. Those committed to their long term health who also tensed their calf muscles were more likely to drink more of the vinegar.

In another test, subjects had to choose whether to look at disturbing images of post-earthquake Haiti as part of an effort to solicit donations. Half clenched their fists, half didn't. And a much larger percentage of those who clenched were able to watch the images and pledge to help.

Another test involved snack choices. Subjects who had health as a priority and who tightened their fingers were more likely to choose healthful snacks than non-clenchers. The study is in the Journal of Consumer Research.

So the next time you're faced with a choice that takes self-control, clench your fist or firm that bicep. Your will might firm up, too.

Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.