Have you ever been sure someone was lying to you? You may have been picking up on subconscious clues from their body language using lessons learned from social media.
It’s easy to find an authority on anything online, but among the many self-proclaimed body language experts there are also more recognised professionals – including psychologists and former FBI interrogators – eager and willing to explain how to spot the subtler, non-verbal signs of a lie.
Whoever the guidance comes from, if you’re trying to spot a lie in something other than a person’s words, you’re advised to watch for all sorts of signs: eye contact, posture, unconscious motions, microexpressions and other giveaways of a falsehood. But is it really that simple?
“Researchers have spent decades trying to identify … a behavioural cue that can help you to separate liars from truth tellers,” says Leanne ten Brinke, an associate professor and director of the Truth and Trust Lab at the University of British Columbia-Okanagan, in Canada. “The short answer to that question is really no. There’s no ‘Pinocchio’s nose’.”
That said, there may be some hope for learning to read body language better. Some research shows correlations between certain behaviours and deception, which might theoretically allow us to train ourselves to sense lies. But take heed: you’ll likely never become an infallible human lie detector.
Hidden signals
As a human being, it’s almost impossible to not communicate with your body.
“Body language is just any movements from the body that people try to interpret,” says Geoff Beattie, a psychology professor at Edge Hill University, in the north-west of England, who studies nonverbal communication. “Some body signals are sent out intentionally and some are sent out unintentionally.”
That includes using your hands to punctuate your words, raising your eyebrows, crossing your arms across your chest, smiling, frowning, smizing (conveying warmth with your eyes) and more subtle movements like a slightly curled lip or narrowed eyes.
Body language is hugely important to human communication – just think how much richer an interaction feels in person versus over the phone. It’s no stretch to think we can uncover hidden information by paying attention to the way someone moves their hands or squints their eyes.
Beattie has begun to explore that idea by more rigorously tracking how people’s movements align with the content of their speech, for example by lining up hand movements with words. In studies of people in the lab he says he’s found evidence for a kind of separation of information between the two.
“They put part of the message in the speech and part of the message in the accompanying nonverbal behaviour,” he says.
Further, body movements seem to be more unconscious than speech, potentially making them harder to fake. In one study, Beattie and his colleagues asked participants to narrate a story twice, introducing false details in one of the versions.
They found people used fewer hand movements when they were lying and their hand movements even sometimes contradicted their words. The takeaway is that gestures that don’t align with speech could potentially give away a liar.
“It’s just too much to think about,” Beattie explains. “You’re focusing on getting the speech right. And the gestural movement, which is the unconscious [part], is still communicating the actual state of affairs.”
These subtle tells may also show up in our faces. Ten Brinke has studied videos of real people appearing on TV to plead for information about a missing relative. About half of the people in her dataset turned out to be lying (they were later convicted of killing the missing relative), while the rest were likely telling the truth.
She found similar, subtle facial tells on the guilty subjects, including masking smiles and incomplete expressions of grief. A follow-up study using different videos of relatives asking for information found those same facial tells in the liars, too.
But while it may be true that our bodies betray us when we’re lying, whether anyone can pick up those signals is another question entirely.
Face the facts
Social media is filled with bold claims about body language. On TikTok, the psychologist Dr Julie (full name Julia Smith) lists a few signs someone might be lying, including avoiding eye contact, fidgeting and signs of self-soothing like pulling on the ears.
Similarly, self-described hypnotist and brain hacker Keith Barry urges his viewers to watch for people who scratch their noses, and argues we can train our brains to look for tiny facial expressions that pinpoint lies.
These kinds of simple signs aren’t likely to be all that much help, experts say. Eye contact, in particular, has never been shown by reputable studies to reveal lies. Other ‘signs’, like fidgeting or specific movements, might be connected to any number of other behaviours and aren’t a reliable sign of lying, either.
“What has been shown, for quite a long time now, is that in face-to-face interaction nonverbal behaviour is a very poor indicator that someone is a liar,” says Vincent Denault, a professor at the University of Montreal’s School of Criminology, in Canada, and co-founder of the Center for Studies in Nonverbal Communication Sciences.
“There is no gesture or facial expression that’s always there when someone’s lying and never there when someone’s telling the truth.”
Relying on individual gestures, whether it’s eye, hand or mouth movements, or other behaviours, will almost never work, according to the most rigorous studies. What’s more, a single behaviour, like eye contact, could be quite easy to fake even if it were a tell.
Body language can differ between cultures, too. It can be considered impolite in many Asian countries to maintain eye contact while talking with someone, for example, while smiling can mean different things depending on the cultural context.
Some social media creators urge their viewers to establish a baseline of behaviour first, and then look for deviations that might indicate a lie. That could be helpful, but, Beattie argues, it’s probably far harder than most people realise.
Personal bias concerning someone’s truthfulness can easily sway judgements, he says, and suspicious behaviour has a range of different explanations that go beyond lies only.
“There’s a whole set of behaviours that are influenced by other behaviours. And I think as human beings and lie detectors, we’re not very sensitive to them,” he says.
Ten Brinke adds that people often establish baselines by asking questions on topics that are vastly different from the one they’re trying to detect deception in. Asking someone their name is quite different from asking them whether they stole a car, for example.
“I would be surprised if you didn’t see behavioural differences, but they could be just due to the nature of the questions,” she says.
Another concept that might help detect lies is micro-expressions: quick, subtle and typically unconscious facial movements. This might include a wrinkled nose to indicate disgust, or a fleeting smile, usually visible for just tenths of a second.
Some researchers argue they represent the ‘leakage’ of genuine emotions, and that we may be able to learn to recognise them and use that knowledge to discern someone’s true emotional state.
While micro-expressions are likely present when people lie, Beattie says, it’s unlikely that they’ll be of much use to most people. “You have to train yourself to be much more sensitive to the features of the human face,” he says.
Ten Brinke found as much in a 2008 study that asked participants to mask their true emotions.
High-speed video cameras found evidence of fleeting, inconsistent expressions that aligned with emotional masking, but when participants were asked to guess who was lying, they did little better than chance. “I think there’s a lot of room for humility and doubt when it comes to our ability to detect deception,” she says.
It doesn’t help matters that studying lies in the psychology laboratory is a difficult task to begin with. Study participants are usually told upfront that they’re being asked to lie. Further, the stakes simply aren’t the same as in the real world, where some lies carry significant consequences.
That means the associations found in labs between body language and lies may not carry through to real life.
That’s almost certainly true for one of the most popularly cited statistics about body language. A 1967 study by psychologist Prof Albert Mehrabian claimed that vocal tone and facial expression accounted for 93 per cent of communication, while the words themselves made up just seven per cent.
That study had participants listen to single words delivered by a single person, while the tone of voice and facial expressions that accompanied them varied. But this doesn’t match the range and variety of normal human communication, argues Beattie, who says he’s replicated similar studies and found that the results didn’t hold.
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Gesture and justice
Despite the difficulty of detecting lies, and the relative paucity of good science behind the concept, there has never been a shortage of those claiming they can pinpoint a liar. While spotting lies could be relatively harmless in day-to-day life, there are some places, like the justice system, where the consequences can be far more serious.
Erroneous beliefs about body language have indeed shown up in court cases, where they can make the difference between freedom and incarceration for a defendant. If a judge or jury decides a witness isn’t credible, it can taint their testimony and, similarly, ‘guilty’ behaviour can bias decisions.
In a 2024 paper, Denault looked at 602 cases from the Australian court system, and found body language was directly referenced in 45 of these to establish the credibility of a witness. In a different study, ten Brinke asked participants to evaluate a fictional legal case after being shown a photo of the suspect.
The participants needed less evidence to decide suspects they’d previously identified as ‘untrustworthy-looking’ were guilty, and were more confident in their decisions, she found.
That implicit trust in body language is contradicted by the scientific evidence, according to Denault: humans’ ability to make inferences about a person’s thoughts or character may be weaker than we typically think.
Some courts agree. One Colorado judge reversed a court sentence that hinged, in part, on how a defendant’s body language changed during questioning by a police officer, after noting previous cases that found body language to be inadmissible as evidence of guilt.
But body language continues to be used to imply a party’s guilt.
For example, the criminal complaint against Luigi Mangione, who is accused of killing the United Healthcare CEO in New York City on 4 December 2024, explicitly mentions his body language. When asked by a police officer if he’d been to New York recently, Mangione “became quiet and started to shake,” the complaint notes.
The fact that it’s mentioned in official documentation suggests the authorities thought body language said something important about Mangione, Denault says. “The problem is what would have happened if someone innocent also shook and became quiet,” he says.
“And I can tell you a million circumstances where someone honest could start to shake and be quiet.”
Mangione has pleaded not guilty to all charges brought against him in connection with the incident, and the matter is yet to come to trial. The significance of, and weight given to, the references to his body language is therefore, as yet, unknown.
Between the lines
If there is one clear takeaway from the research on using body language to detect lies, it is to exercise a healthy amount of caution.
“You have to be really, really cautious about this,” Beattie says. “It’s one of those areas of psychology where I think there’s just so much more work to be done.”
Factors like personal bias, the diversity of human behaviour and a tendency to focus on the wrong signals make it exceedingly challenging to accurately detect lies based on someone’s behaviour.
One potential avenue is to look at hand gestures and see whether they correlate with speech, Beattie says, based on his research. Smiles that fade too quickly are another potential clue, he adds.
Still, Beattie advises caution for those setting out to hunt down lies.
Cultural differences can play into behaviours (for example, whether eye contact is considered appropriate or not), and not everyone might act the same way when they’re lying. Some people actually enjoy lying, meaning they might react differently when telling a lie.
“I think it’s complicated, it’s difficult,” he says. “There might be cues there, but most people will miss them.”
Ten Brinke says it might actually be better to avoid body language altogether. Studies show that verbal cues, like how detailed someone’s response is, or how confidently they state things, might be a more reliable lie detector. She says her research has shown that basic training on verbal cues helped people get better at detecting lies.
“We’re not great at holding all kinds of different cues in our mind and then trying to do some sort of complex algorithm to come up with a judgment at the end,” she says. “You would be better off just focusing on one thing, like ‘how detailed was that response?’”
Even so, it’s doubtful anyone will ever be able to pinpoint a lie every time, or even most of the time. We may believe we can spot a liar – but we may simply be lying to ourselves.
About our experts
Leanne ten Brinke is an associate professor and director of the Truth and Trust Lab at the University of British Columbia-Okanagan, in Canada. She is published in various journals such as Personal and Social Psychology Bulletin, Personality and Individual Differences and Applied Cognitive Psychology.
Geoff Beattie is a psychology professor at Edge Hill University and researches nonverbal behaviour. He has been published in many different journals including Nature, Journal of Experimental Psychology and Semiotica.
Vincent Denault is a professor at the University of Montreal’s School of Criminology, in Canada, and co-founder of the Center for Studies in Nonverbal Communication Sciences. His work is published in Body Language Communication, Journal of Forensic Psychology Research and Practice and Journal of Nonverbal Behavior to name a few journals.
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