"Don't rely on 1 thing," says Phil Houston, CEO of QVerity, which provides behavioral analysis and screening services to its clients. "The more behaviors you can see, the more likely they're not being candid," he says. Houston is also a former CIA agent and co-author of "Spy the Lie."
How often do we lie?
- Study found 60% of people lied at least once during 10-minute conversation.
- Average number of lies told during that conversation? 2 to 3.
Source: 2002 research by University of Massachusetts psychologist Robert Feldman.
2. Watch the feet
If you ask a pointed question and notice foot shuffling, pay attention.
"Even if they're trying to maintain composure, the feet don't lie," says Lillian Glass, author of "The Body Language of Liars." "The truth leaks out through their feet."
Feet are the "anchor points" when someone is standing, says Houston. If the person is sitting, he may swivel in his chair or fidget.
3. Look for 'grooming'
"Notice whether they're grooming themselves or their surroundings," Houston says. "The significance is it may indicate a discomfort with what they're about to tell you."
"They're dressing themselves up to look more presentable, so you'll buy into what they're saying."
4. Beware of verbal loopholes
Listen for "something we call 'exclusionary qualifiers,'" says Houston. Words such as "fundamentally" or "I think" before an answer give the speaker more latitude, he says.
Even when you "recognize exclusionary qualifiers, they seem harmless," he says. "But sometimes whatever they carve out is a big deal."
5. Listen to the way numbers are presented
"The first time a number's put on the table, listen very carefully to how they present that number," Houston says.
Do they just put it right out there, or do they keep promoting it and trying to convince you that it's a good number?
"The more they try to sell, the more indication to you that there is some wiggle room in that number," he says.
6. Study stress reactions that are tougher to control
Many times, if people lick their lips, "That means they have cotton mouth," Glass says. "It's because the autonomic nervous system takes over." (The autonomic nervous system regulates our internal organs -- think heart rate -- and functions involuntarily.)
Other tells: You may see someone swallow hard, she says. And many people blink rapidly when they're "not being forthright," she says.
One reaction that's likely impossible to control is pupil size, Morgan says.
The challenge is deciphering what it means. Those widening pupils could signal the salesman likes you and is offering a great deal, he says. Or it could mean that he's gleefully moving in for the kill.