To sharpen your lie detection ability, follow these seven guidelines:

1. Begin with a baseline

The first and most important step in deception detection is observing a person’s baseline behavior under relaxed or generally stress-free conditions so that later you can spot those meaningful deviations that signal stress and possible deception.

While you are chatting informally, notice how people’s bodies look when they are relaxed. (What is their normal amount of eye contact and blink rate? What kind of gestures do they use most frequently? What postures do they assume when comfortable? What is their pace of speech and tone of voice?)

2. Watch for the initial signs of stress

There is no single verbal or nonverbal behavior that automatically means a person is lying. In fact, much of “lie detection” is actually stress detection.

To relieve this nervous tension, liars may use pacifying gestures (rubbing their necks, bouncing their heels, fidgeting with jewelry, etc.) Their feet may even point to the door in a nonverbal signal that they would like to “escape.” But our first response to stress (before we ready ourselves to fight or flee) is to freeze. So also pay attention if your usually animated colleague suddenly stops gesturing, has a forced or frozen smile, holds her breath, or tightly locks her ankles.

By the way: The biggest myth around deception is that liars can’t look you in the eyes. In fact, some don’t (especially small children), but polished liars may actually give too much eye contact. Two eye signals that are more accurate signs of stress and potential dishonesty are pupil dilation and a change in blink rate.

3. Listen carefully to what people are telling you

People may tell you the (literal) truth. If your boss says “I’m thinking of recommending you for the position,” that is exactly what she means. She has not told you she did recommend you. She has not told you she will recommend you. All she said is that she is thinking about doing so. In the same way, if your colleague states, “That’s all I can tell you,” believe him. He can’t or won’t tell you more … but remember, that doesn’t mean this is all he knows.

Because of the mental effort it takes to tell a bald-faced lie, many people prefer to circumvent the truth with selective wording. They may avoid answering your question exactly as asked or they might say something that sounds like a denial, but isn’t. For example: If you accused a liar of spreading malicious gossip about a co-worker, he might respond, “Do I look like someone who would do that?” instead of saying “I didn’t do it.” Liars may even go into attack mode and try to impeach your credibility or competence with statements meant to put you off- track or even to intimidate: “Why are you wasting my time with this stuff?” or “Do you know how long I’ve been doing this job?”

Stay especially alert when people tell you what they are not doing (“I don’t want you to take this the wrong way,” or “It’s not that I have anything to hide”). Most often, that’s a lie. Of course, you’ll have greater success in detecting verbal deceit cues if you and the person you are dealing with are from the same culture and speak the same language.

4. Stay alert for “emotional faking”

There are seven basic emotions that are shared, recognized, and expressed the same way around the world. Discovered and categorized by Paul Ekman and his colleagues at the University of California in San Francisco, the universal emotional expressions are joy, surprise, sadness, anger, fear, disgust, and contempt.

In monitoring emotional reactions, look also for simulated emotions, where people try to convince others that they feel a certain way by simulating the facial expression associated with that feeling. You may even get a gut feeling that your colleague’s “terribly sincere furrowed-brow” or exaggerated display of anger feels somehow excessive. Realize, too, that any expression you see displayed for more than five to ten seconds is almost certainly being faked.

5. Notice incongruence

When thoughts and words are in sync (when people believe what they’re saying) you can see it in their body language as their gestures, facial expressions and body postures fall into natural alignment with their verbal messages. Incongruence occurs when someone’s nonverbal behavior contradicts her words – such as a side-to-side headshake while saying “yes” or a slight shoulder shrug (which is a sign of uncertainty) when assuring you they’re “absolutely positive.” Often, verbal-nonverbal incongruence is a sign of intentional deceit. At the very least, it shows that there is an inner conflict of some sort between what the person is thinking and what she is saying.

6. Look for the “telltale four”

Nonverbal cues often occur in what is called a “gesture cluster” – a group of movements, postures and actions that reinforce a common point. Clusters play a key role in your growing ability to spot lies. A single nonverbal cue can have several meanings or mean nothing at all, but when it is reinforced by at least two other nonverbal signals, the meaning becomes more apparent.

7. Recognize the issues that interfere with your ability to detect falsehoods

As previously stated, the act of lying triggers a heightened and observable stress response most people. But not always and not in everyone:

• Not all people display the same degree of emotion.
• Not all liars (especially if polished or pathological) show any signs of stress or guilt.
• Not all lies trigger a stress reaction. (Social lies, for example, are so much a part of daily life that they hardly ever distress the sender.)
• Not all stress signals indicate a lie. Truthful people may exhibit anxiety for a variety of perfectly innocent reasons — including the fear of not being believed or discomfort speaking about embarrassing or emotionally arousing topics.

And sometimes our own biases get in the way. Research shows that surprisingly small factors – such as where we meet someone, what they wear, what their voices sound like, whether their posture mimics ours, if they mention the names of people we know or admire, if they flatter us, if they are attractive and charming, or if they remind us of ourselves – can enhance their credibility to the extent that it actually nullifies our ability to make sound judgments about them. When we put our trust in a deceptive co-worker or hire someone we haven’t properly investigated, it may not be due to their skill as a liar, but more about our own unconscious biases, vanities, desires, and self-deceptions.

Lies and liars can kill collaboration and innovation, damage teams and organizations — and sometimes even destroy reputations and careers. Sharpening your deception detection skills (while recognizing your own biases) is a savvy resolution.