How to Spot a Liar: Psychologists Say Forget Body Language Entirely

How to spot a liar isn’t about watching their hands. Forget the nose-scratch. Forget the shifty eyes. Psychologists say we’ve been looking in the wrong place for decades. The real tell isn’t in their body. It’s in their words.

Quick Facts

• Researchers say verbal cues detect lies far more reliably than body language
• Liars often become more still, not more fidgety, under pressure
• A technique called the Strategic Use of Evidence can expose lies without revealing what you already know
• Asking someone to recall events backwards tends to trip up liars far more than truth-tellers

How to Spot a Liar: Why Body Language Doesn’t Work

For years, popular wisdom said liars fidget. They touch their face. They avoid eye contact. None of that holds up, according to Dr Sharon Leal, a psychologist at the University of Portsmouth who studies deception.

“There’s nothing in it scientifically to show looking for non-verbal signs actually works,” Leal says. “Forget all the extraneous movements, fidgeting, blinking, gaze aversion, it’s not there. If anything, it’s the opposite. Liars tend to be more still.”

That stillness makes sense once you understand what’s actually happening in a liar’s brain. Lying takes real mental effort. You have to invent a story, remember it, and watch your own behavior at the same time, all while reading the person you’re lying to. “You’re monitoring your own behaviour and trying not to look nervous,” Leal explains. “We know from MRI scans that the truth pops up first, and that has to be suppressed, so all of these things add to cognitive load.” Managing that load leaves less mental bandwidth left over for fidgeting.

How to Spot a Liar: It’s All About the Words

If body language is a dead end, what actually works? Psychologists have shifted almost entirely toward analyzing what people say, not how they move while saying it. A handful of interview techniques have emerged that reliably separate truth-tellers from liars.

The Strategic Use of Evidence

One method, called Strategic Use of Evidence, works by asking questions about an event without revealing what the questioner already knows. Someone with nothing to hide tends to talk freely and volunteer detail. Someone lying tends to deny being there at all, or dodge specifics whenever possible.

It’s a subtle trap. The liar doesn’t know exactly what the questioner already knows, so every vague answer risks contradicting evidence that’s already sitting on the table.

The Verifiability Approach

A related technique, the Verifiability Approach, asks people to offer details that could actually be checked. Think names of other people who were present, or specific, confirmable facts. Research shows truth-tellers volunteer this kind of checkable detail far more readily than liars do.

Liars tend to avoid naming witnesses or offering anything a questioner could later verify. It’s not always a conscious choice. It’s simply safer to stay vague.

Tell It Again, Backwards

Another approach, called cognitive credibility assessment, asks someone to tell their story multiple times. Truth-tellers tend to add new, consistent details with each retelling. Liars tend to stick rigidly to the same simplified script, since deviating risks creating a contradiction they’ll have to explain.

Asking someone to recount events in reverse order makes this even harder to fake. People telling the truth can lean on real memory, even scrambled out of order. Liars, working from a rehearsed script, often stumble badly when forced to reconstruct it backwards.

The Devil’s Advocate Trick

A newer study led by Leal and Professor Aldert Vrij tested something called the devil’s advocate protocol. Interviewees were asked to explain why they held a certain opinion, and then asked to argue the opposite side.

Truth-tellers showed a clear difference. They spoke with far more passion and eloquence defending their real opinion than arguing against it. Liars showed something strange instead: roughly equal enthusiasm for both sides. Ironically, that consistency is itself a red flag. Liars tend to believe that appearing inconsistent will make them look suspicious, so they oversmooth their answers instead, and that oversmoothing becomes the tell.

Lying by Leaving Things Out

Not every lie is a flat-out fabrication. Sometimes people lie by omission, technically telling the truth while hiding the one detail that matters. Someone asked where they were might honestly say “at a friend’s house,” while conveniently leaving out a twenty-minute detour somewhere they shouldn’t have been.

Leal’s team has found that the same verbal cues that catch outright lies also catch omissions: vague answers, reluctance to volunteer detail, inconsistency under follow-up questioning. “A lot of people think when they lie by omission, it’s not a lie,” Leal says. “But it is still a lie, and the verbal cues are still there.”

Why the Body Language Myth Won’t Die

If the science is this clear, why does the ear-tug, nose-scratch myth refuse to go away? Leal has a theory involving simple confirmation bias. Picture two customs officers. One searches anyone who touches their ear. The other searches anyone who makes intense eye contact. Both will occasionally catch someone. Both will walk away convinced their method works, without ever checking how many people they missed, or how many innocent people they wrongly flagged.

Once you understand how much mental effort lying actually takes, it’s easier to see why the words matter more than the fidgeting, something that ties back to how much cognitive load the brain can realistically handle at once, a topic we explore further in our guide to everyday habits that keep your brain sharp under pressure.

Putting It Into Practice

Learning how to spot a liar in everyday life doesn’t require formal interrogation training. A few habits borrowed from these techniques go a long way. Ask open questions instead of yes-or-no ones. Let people talk. Truth-tellers tend to fill silence with detail, while liars often wait for you to lead.

If something feels off, ask the person to explain it again later, in a different order. Small inconsistencies that show up between two honest retellings are usually harmless. Larger contradictions, especially around specific, checkable details, are worth paying closer attention to.

Above all, resist the urge to read too much into crossed arms or a wandering gaze. The evidence just isn’t there. Save your attention for the words instead.

Frequently Asked Questions

How can you tell if someone is lying?
Psychologists say verbal cues work far better than body language. Vague answers, reluctance to offer checkable details, and inconsistency under follow-up questions are stronger indicators than fidgeting or eye contact.

Do liars avoid eye contact?
Not reliably. Research has found no solid scientific support for eye contact, fidgeting, or other body language cues as accurate signs of lying. Liars often appear calmer and more still than truth-tellers, not less.

What is the Strategic Use of Evidence technique?
It’s an interview method where the questioner asks about an event without revealing what evidence they already have. Truth-tellers tend to speak freely, while liars often deny involvement or avoid specifics.

Can lies of omission be detected the same way as outright lies?
Yes. Research suggests the same verbal cues, vague answers, reluctance to volunteer detail, and inconsistency under questioning, are just as effective at exposing lies of omission as they are at catching direct lies.

Final Thoughts

Learning how to spot a liar means unlearning almost everything popular culture taught us. It’s not about a twitchy eye or a scratched nose. It’s about listening closely to what someone says, how freely they say it, and whether their story holds up when you ask them to tell it a different way. The next time you’re trying to figure out if someone’s telling the truth, close your eyes and just listen.

Once you know how to spot a liar through words instead of gestures, it’s hard to unsee.

Source: BBC Science Focus, “The simple questions that can expose any liar, according to psychologists”