7 ways your body betrays you when you're nervous

The problem with trying to conceal anxiety - in any situation - is that we've evolved to do exactly the opposite.

According to Joe Navarro, a former FBI agent and the author of "What Every BODY is saying," we're hardwired to display anxiety and to recognize it in others as well. Back in our caveman days, this was a means of quickly recognizing danger.

Here are some of the most common universal, nonverbal expressions of nervousness that are pretty hard to control.