How to Actually Spot a Liar (According to the FBI, Not TikTok)

Forget the nose-touching, the shifty eyes, the crossed arms. Real behavioural experts say the tells you've been taught to look for barely exist.

Short version: Joe Navarro, a former FBI agent and founding member of the Bureau's Behavioral Analysis Unit, has said plainly that there's no single, reliable "tell" that proves someone is lying. What actually works, according to genuine FBI-trained interviewers, is comparing a story against itself, over time and under gentle pressure — including a genuinely clever technique: asking someone to tell their story backward.

A lot of popular "how to spot a liar" advice is built on shaky ground. The people who actually did this professionally, for decades, tend to say something much more modest and much more useful.

What a genuine FBI behavioural expert actually says

Joe Navarro spent 25 years with the FBI, including as a founding member of its elite Behavioral Analysis Unit, and later wrote the bestselling book on reading nonverbal behaviour. Asked directly about the classic "tells" most people believe in, he's been refreshingly honest: there is no single behaviour that reliably proves deception, no equivalent of Pinocchio's nose. What he looks for instead is more subtle — general signs of psychological discomfort or distress, which can just as easily come from an innocent person's nerves as from an actual lie. In other words, even one of the most credentialed behavioural experts alive won't claim there's a magic tell, and neither should anyone else.

If someone with 25 years at the FBI's Behavioral Analysis Unit says there's no reliable single tell, that's worth taking more seriously than a listicle promising to teach you one.

The technique that's actually genuinely clever

LaRae Quy, who spent 23 years as an FBI counterintelligence agent, has shared a practical technique worth knowing: ask someone to tell their story backward, out of order. A rehearsed or fabricated account is typically memorised forward, like a script, and recalling it in reverse tends to disrupt that rehearsal, causing inconsistencies to surface. A genuine memory, by contrast, doesn't rely on a fixed sequence in the same way, and people recalling something real often manage this far more easily than someone reciting a prepared version of events.

How to actually use this

• Drop the myth-hunting. Stop scanning for a nervous tell that credible experts themselves say doesn't reliably exist.
• Ask one genuine follow-up question, gently. Notice whether the detail holds up or contracts.
• Try the backward technique, if it fits the moment. Even casually, asking someone to recall something in a different order than they first told it can be genuinely revealing.
• Compare the story against itself over time. The real evidence was never in a single conversation. It's in whether the account stays consistent across several.

Frequently asked questions

Is there a reliable body language sign that someone is lying?+

According to Joe Navarro, a former FBI Behavioral Analysis Unit agent, there is no single reliable behavioural sign of deception. What can be observed are general signs of psychological discomfort, which may stem from lying or from unrelated stress.

Why does asking someone to tell their story backward help spot a lie?+

Fabricated stories are often rehearsed in a fixed, forward sequence. Recalling events out of order can disrupt this rehearsal and reveal inconsistencies, whereas genuine memories tend to be recalled more flexibly regardless of sequence.

Love, Vikki x