When Joe Navarro began his career as an FBI agent, he discovered a need to study people's body language and started a nonverbal communication program within the agency. For 25 years, Joe used this behavioral information to catch spies. Jean talks with Joe, who's now retired, about his book What Every Body Is Saying: An Ex-FBI Agent's Guide to Speed-Reading People. Joe talks about what body language to look for in job interviews and business negotiations, and how to know if you're being scammed.

When reading someone else's behavior, Joe says to look for physical signs of comfort or discomfort, such as someone moving his forehead, squinting his eyes, touching his neck or making his lips disappear. "When you begin to see signs of discomfort on the part of the person you're talking to, they begin to shut down," Joe says. On the other hand, smiling and head tilts are good indicators of comfort. "A head tilt is the most powerful display of comfort because we only show our necks when we're truly comfortable," Joe says.

Joe also offers advice on how to tell if someone is trying to scam you:

• The person becomes too friendly too fast. Joe says the average person merely presents his case, but someone trying to scam you will try to convince you over and over that it's a good deal.
• The person violates your personal space. "When someone violates our space, we feel uncomfortable," Joe says. "To relieve that stress, we end up signing the papers just to get them away from us. This is especially a problem for the elderly."
• The person gives you too much information to fluster you. "They machine gun you with so many facts and figures that they leave you dizzy," Joe says. "An honest business person will actually slow things down, take the time to make sure that you make an informed decision."