How to Tell If Someone Is Lying to You, According to Body Language Experts (2024)

All human beings possess the ability to lie. And many of us do — multiple studies have suggested that, on average, Americans tell one or two lies a day. Fortunately, experts say there are ways to spot signs of untruthfulness.

To identify a fib, you first have to have a baseline for how someone acts when they’re being honest, says Traci Brown, body language expert and author of How to Detect Lies, Fraud and Identity Theft: Field Guide. For example, watch how someone responds to a basic question such as, “Where are you from?” Where do their eyes go? How does their voice sound?

Once you’ve established that baseline, look for shifts in behavior in four different categories: bodily movements, facial expressions, tone of voice and content of speech, says Dr. Lillian Glass, author of The Body Language of Liars. “Those are the codes of communication,” she says.

The signs however, aren’t foolproof — if someone is uncomfortable in their seat, they may fidget; if someone is nervous, their voice may crack.

“There is debate within the healthcare community, and certainly in the area of mental health, about what are reliable body language tips that can possibly indicate that someone is lying,” says Dr. Gary Brown, a licensed family and marriage therapist based in Los Angeles. Our own perceptions can impede our ability to correctly interpret the signs, adds Dr. Jenny Taitz, a Los Angeles-based clinical psychologist. “It can be tough to accurately interpret someone through their body language since someone may feel tense or look uneasy for so many reasons,” she says. “For example, it’s easy to imagine shirking eye contact, as people often associate with lying, for any number of reasons from feeling socially anxious to bored to ashamed because you know you’re lying. We’re not always as adept at reading others as we assume.”

Still, there are signals that vetted body language experts suggest keeping an eye out for.

Body Cues

The hands: Liars tend to use gestures with their hands after they speak as opposed to during or before a conversation, says Traci Brown, who has participated in a deception training program with members of the FBI and occasionally helps work on investigations. “The mind is doing too many things including making up the story, figuring out if they’re being believed and adding to the story accordingly,” she says. “So normal gesturing that might normally happen just before a statement happens after the statement.”

A 2015 study conducted by the University of Michigan looked at 120 media clips of high-stakes court cases in order to understand how people behave when lying versus when they’re being truthful. The study found that those who lie are more likely to gesture with both of their hands than those who are telling the truth — people gestured with both of their hands in 40% of the lying clips, compared to 25% of the truthful clips.

When people are being dishonest, they also tend to face their palms away from you, says Traci Brown, who regularly gives keynote speeches at financial institutions to help them detect and prevent fraud. It’s an unconscious signal that they’re holding back information, emotions or even lying, she says. “They may put them in their pockets or even slide them under the table.”

Itching and fidgeting: Rocking the body back and forth, co*cking the head to the side or shuffling the feet can also be signs of deception, says Glass, who completed a post-doctoral fellowship at UCLA focusing on Psychology and Verbal and Non-Verbal Communication. Fluctuations in the autonomic nervous system, which regulates bodily functions, can also have an effect, she says. When people are nervous, these fluctuations in the nervous system can prompt people to feel itches or tingles in their body, which in turn can cause more fidgeting, she explains.

Research conducted by UCLA psychology professor R. Edward Geiselman drew a similar conclusion, finding that people tend to display “grooming behaviors,” such as playing with their hair, when being dishonest.

Facial Cues

The eyes: Someone who is lying might stare or look away at a crucial moment, says Glass — a possible sign they’re moving their eyes around as they try to think about what to say next.

The research conducted by Geiselman at UCLA corroborated this, finding that people sometimes look away briefly when lying. The 2015 study conducted by the University of Michigan also found that those who lied were more likely to stare than those who were truthful — so much so that 70% of the clips of people lying showed them staring directly at the people they were lying to.

There is still some debate over this, however. A 2012 study published in Plos One debunked the concept that people look in a specific direction when they are dishonest. And while there is a possibility of reading too much into someone’s mannerisms, Glass maintains that there is some truth to be gleamed from the eyes.

The mouth: Rolling the lips back to the point where they almost disappear could be a sign someone is lying by omission, according to Traci Brown. “It’s been my experience that, when people do that, they’re holding back emotions or facts,” she says.

The research conducted at UCLA found that people who lie are more likely to purse their lips when asked sensitive questions. Pursing the lips could also mean someone doesn’t want to engage in the conversation at hand, says Glass. “It’s an instinctive reflex meaning you don’t want to speak,” she says.

Change in complexion: Ever notice someone go white as a ghost when speaking? That could be a sign of untruthfulness, says Glass, who says this signals blood rushing out of the face.

Sweating or dryness: Autonomic nervous system changes can trigger liars to sweat in the T-area of the face (upper lip, forehead, chin and around the mouth) or have dryness in the mouth and eyes — the person might excessively blink or squint, lick or bite their lips or swallow hard, according to Glass.

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Tone of Voice

A high-pitched voice: When people are nervous, the muscles in the vocal cords might tighten up (an instinctive response to stress), leading the voice to sound very high-pitched, says Glass. You might also notice a creak in someone’s voice. Clearing the throat, a means of coping with the discomfort of the tightened muscles, can also at times signal dishonesty, she says.

A sudden change of volume: People who fib also tend to raise their voices, says Glass. “Sometimes you’ll get louder because you’ll get defensive,” she adds.

Content of Speech

Phrases such as ‘I want to be honest with you,’ ‘honestly’ or ‘let me tell you the truth’: These can be signs someone may be trying a little too hard to convince you of their honesty, according to Glass.

Using words such as, ‘uh,’ ‘like’ and ‘um’: The research conducted at the University of Michigan found “speaking with more vocal fill” to be a common indicator of deception. Glass says that people tend to use these words more when they’re trying to buy time to figure out what they’re going to say next.

Slip-ups: Most of us are not natural-born liars, Glass notes. So sometimes, we let the truth slip out. Notice someone saying things like, “I was fired — no, wait, I mean I quit” or “I was out to dinner with So-and-So — wait actually, I was working late.” You might have a liar on your hands, she says.