The Lie About Lie Detection

For decades, police officers have been taught they can spot a liar by watching body language. Gaze aversion, crossed arms, fidgeting, inconsistent speech patterns—these are all presented as telltale signs of deception.

But there’s a problem: science says that’s not true.

Despite widespread belief in “deception detection” techniques, research shows that humans — cops included — are terrible at detecting lies based on nonverbal behavior. These myths not only undermine investigations—they can lead to tragic miscarriages of justice.

It’s time to face the facts and leave behind the pseudoscience.

Myth: You Can Spot a Liar by Their Body Language

Conventional police interrogation training often includes sections on how to detect lies using nonverbal cues. Officers are taught to look for “clusters” of behavior—multiple signs that, together, suggest someone is being deceptive. These include things like:

• Gaze aversion
• Nervous fidgeting
• Inconsistent tone or pacing
• Defensive posture

While instructors usually qualify that “no single behavior proves deception,” they still promote the idea that reading these signs correctly can help identify when someone is lying.

As Dr. Richard Leo (2008) puts it in Police Interrogation and American Justice:

“Although police trainers usually mention that no single non-verbal or verbal behavior is, by itself, indicative of lying or truth telling, they nevertheless teach detectives that they can reliably infer whether a subject is deceptive if they know how to interpret his body language, mannerisms, gestures and style of speech.”

The underlying message is clear: “If you’re trained, you can spot a liar.”

That belief is false.

Fact: There Is No Reliable Nonverbal “Tell” for Lying

Scientific studies consistently show that no body language or behavioral pattern is uniquely linked to deception. People may fidget because they’re nervous, tired, or scared—not because they’re lying. Eye contact can vary wildly depending on culture, personality, or stress—not guilt.

“Numerous controlled studies have shown that people generally are not good intuitive judges of truth and deception.” — Miller & Stiff, 1993

Even professionals with years of experience—detectives, federal agents, and psychologists—perform only slightly better than chance at detecting lies.

• Ekman & O’Sullivan (1991)
• Vrij (1994)
• Ekman, O’Sullivan & Frank (1999)

Most hover around 54% accuracy, barely better than a coin toss.

The Intercept (2020) revealed, via the BlueLeaks archive, that despite the lack of scientific support, some law enforcement agencies continue to rely on discredited deception detection training—even when internal reviews admit the training is pseudoscientific.

The Danger of Overconfidence: Misinterpretation and False Confessions

Believing you can “read people” isn’t just harmless—it’s dangerous.

Officers who are taught to see gaze aversion or fidgeting as signs of deception may wrongly conclude that a truthful person is lying. That belief leads to confirmation bias, escalating interrogations, tunnel vision, and—too often—false confessions.

As Casey Bastian wrote in Criminal Legal News (2023):

“Law enforcement’s continued reliance on discredited deception detection techniques… is a leading cause of miscarriages of justice.”

The problem isn’t just that these methods don’t work—it’s that officers believe they do. That misplaced confidence can ruin lives because once an investigator is convinced a suspect is lying, they may then search out information that seeks to support their theory.

The “Cluster” Theory: Doubling Down on Bad Science

Some trainers try to add nuance by telling officers to look for clusters of behavior instead of single cues. But this is just putting a scientific-sounding frame around an unscientific idea. If each individual cue is unreliable, combining them doesn’t make the result more accurate.

It just adds to the noise and reinforces bias.

And in practice, once an officer suspects someone is lying, their interpretation of the subject’s behavior tends to match that belief. That’s how innocent people get labeled as deceptive based on nothing more than nerves or stress.

What Actually Works: Science-Based Interviewing

So what’s the alternative?

Instead of trying to “spot a lie,” science-based interviewing focuses on gathering accurate, detailed information. It emphasizes:

• Building rapport instead of confrontation
• Open-ended questions that encourage explanation, not yes/no answers
• Avoiding assumptions about guilt based on behavior
• Information-gathering over confession-hunting

These methods are used by professionals in fields like cognitive psychology, military intelligence, and investigative interviewing units in the U.K., where they’ve seen greater accuracy and fewer false confessions.

Time to Move On

We now know what decades of research has confirmed: you can’t spot a liar by watching their body language. And the more confident you are that you can, the more likely you are to get it wrong.

It’s time for law enforcement to move away from the pseudoscience of deception detection—and toward science-based interviewing methods that actually work.

Because justice demands more than just a good gut feeling.