As a Police Officer, detecting when someone was lying could be a matter of life and death.

If I get it wrong, a dangerous criminal could go free, or an innocent person might get locked up.

The stakes couldn’t be higher.

Everyone gives off clues about their real opinions, motives, and behaviors if you know how to look.

You don’t have to be a cop to benefit from using body language to detect dishonesty. These skills will help at work, at home, and with friends.

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Is body language accurate?

The rule is never to read individual body language cues in isolation. The same mannerisms and rules mean different things depending on the circumstances.

You may have heard someone with folded arms is being defensive. But maybe they’re just cold.

Does someone with their legs crossed in your direction fancy you, or are they getting comfortable?

You must understand body language in clusters and pay attention to a person. The better you know them, the more accurate you’ll be.

One of my strangest encounters was sitting with a man who had murdered his mother with a hammer.

Usually, violent criminals are manic after the crime, but this guy just stared into space for hours.

The highlight of our conversation was his asking to pee. He stood over the toilet for 15 minutes, rocking back and forth.

These bizarre behaviors were his baseline. If I were interviewing him, I would look for deviations from his quiet, calm demeanor — signs of agitation or discomfort.

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The basic principles of body language.

My basic principles are:

• Your body says more than the words you speak.
• Context is everything.
• Never interpret a single signal — look for clusters.
• First, create the baseline, then look for deviation.
• Sudden changes are important.
• Beware of contamination — your body language can affect others.
• Don’t put your emotions and beliefs onto someone else.
• Beware of cultural differences — a firm handshake is valued in the West but seen as aggressive in the Far East.

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Verbal cues of lying.

1. Using a question to answer a question

When a liar is caught with a surprise question, they need more time to think and construct a story. Any sign of stalling might indicate deception.

A significant indicator of buying time is when someone pretends not to hear or understand the question. They might ask you to repeat what you said to buy themselves a few more seconds to think.

2. They ramble.

This includes offering too much information, giving too many details, and stuttering.

When someone lies, they overcompensate to make sure you believe what they’re saying. People think liars are short on detail, so if they remember they ate cornflakes at 6:10 am last Wednesday, they think it makes them sound credible.

3. They use filler words.

Filler words are things like “uh” and “erm.” An increase in these from the baseline might mean you are being told a lie.

Again, the speaker is buying more time to think. When someone’s telling the truth, their speech is direct and specific because they understand what they’re saying.

Telling the truth is easy. Lying requires real effort.

4. They speak fast and loudly.

People who lie tend to get louder and talk faster to get their story out without giving you a chance to get feedback or questions into their narrative.

They blitz you in the hope you don’t notice the inconsistencies in their story.

5. They present an inconsistent story.

Try asking the same question multiple ways to see if their story holds up. If they’re lying, they will need mental gymnastics to keep up.

When you notice a lie or exaggeration, lean into it and start digging. Get used to asking follow-up questions.

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Nonverbal cues of lying.

1. They overcompensate with eye contact.

Liars often overcompensate with eye contact because they have read that shifty people look at the floor and their eyes dart around the room.

Typically, we look into someone’s eyes for 3–5 seconds. We look longer if we have a connection, such as a romantic partner or friend.

2. They blink more.

People blink more when being deceptive by two or three times the average rate.

3. They create physical barriers.

Maybe they use their hand or an object like a cup as a barrier. Perhaps they turn away slightly to subconsciously protect themselves from possible conflict if their lies are revealed.

4. They turn pale.

Even a seasoned liar feels under pressure, and their face is a giveaway, especially the lips and ears.

This area may go pale because the body is getting into fight or flight, and blood is needed elsewhere. Stressful situations make us pale.

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Putting it all together.

First, you must get to know someone as much as possible to establish the baseline.

Sometimes I had an hour or two to get to know my interviewee, so you must work with what you’ve got. But the longer you have, the better.

Next, look for inconsistencies between the baseline and the person’s current words and gestures.

If you notice a friend always seems to clear their throat when nervous, be careful if he asks for a change in an arrangement while doing this. Whether or not it’s suspicious will need further investigation.

The single throat clear might alert you, but you need confirmation signals to make any judgment. If, while clearing his throat, he scratches his head and shuffles his feet, you may be on to something.

I’ve interviewed suspects who started the interrogation slouched on their chairs, smiling and engaging in smug conversation.

When the questions got more brutal, some would tense up, some had rage written across their face, and they would suddenly become less smug and chatty.

Once, I was investigating a missing person. I met her boyfriend, and he was the perfect host. He was pleasant and polite, and he even gave me cookies.

But his calm demeanor struck me as odd. This is what he thought we expected to see from an innocent man. He was putting on a show.

I was right — he’d murdered her.

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Look for consistency.

Now you have your baseline, have found inconsistencies, and are looking at clusters, there’s one more thing you have to do.

Does the person you’re observing repeat the same suspicious mannerisms with others? Observe how they interact with others and see if their body language is consistent with your observations.

If someone’s attracted to someone in your group, their behavior will be very different from how they are with you.

Perhaps their eyebrows arch more, their facial muscles relax, and blood flows to their lips.

The more time you have, the more accurate you’ll be in evaluating these patterns.

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Conclusion.

You have to avoid overreliance on body language cues. I’ve never arrested or charged someone with a crime based on a cluster of signals.

I use body language to guide me — it shows me where to explore, how to handle my approach, and the correct amount of pressure to exert on a suspect.

So don’t live your life according to the body language cues you receive from others. Use them to enhance your relationships.

You have to fall in love with people-watching. Take your laptop to a cafe and hang out when you have spare time.

Observe people and try to work out as much as possible about them as the world passes. You won’t have the luxury of getting to know them first, but some cues will start to stand out.

Gain an overview of someone’s personality and then narrow the clues down to get more specific. You won’t master this overnight, but with practice, you can improve all of your daily interactions.

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This post was previously published on Publishous.

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