Are Police Officers Human Lie Detectors?

Posted by Stone River Criminal Defense Team

Last Updated: November 29, 2024

Science shows police officers are no better at detecting lies than the average person. Their judgments often rely on biases rather than facts, which can lead to wrongful assumptions.
attorney meeting with client at desk

Human Lie Detectors, Like Magic, are not Real

It’s a common belief: police officers claim they can spot a lie just by observing someone. They say signs like avoiding eye contact, staring too much, speaking quickly, or pausing too long reveal dishonesty. But is this true? Can officers really tell when someone is lying?

What the Science Says

Many officers believe their training helps them spot lies. To test this, researchers asked police officers to watch people tell the truth and lie. Then, they asked ordinary people to do the same. The results were clear: officers were no better than average people at detecting lies.

In fact, their accuracy was no better than flipping a coin. Heads, you’re lying. Tails, you’re truthful.

Yet, despite these findings, many judges and prosecutors still trust officers’ instincts. When an officer says, “Based on my training and experience,” it carries weight—even though science says otherwise.

There is No Such Thing as Magic

The idea that police officers can “magically” detect lies is a myth. If this skill were real, imagine what we could do:

  • Catch politicians lying in real time.
  • Confirm if a spouse is cheating without any doubt.
  • Solve crimes instantly.

But magic isn’t real. Police officers aren’t wizards, and they don’t have superhuman powers.

Even more concerning, Utah trains “Drug Recognition Experts” (DREs) to decide whether someone is experiencing a medical emergency or drug impairment—just by interacting with them. If this worked, hospitals could skip blood tests and rely on DREs to save lives. But it doesn’t work that way. Science matters. Magic isn’t real.

What’s Really Going On?

So, what’s happening when an officer thinks they can spot a lie? It’s all about bias.

We all have biases—preconceived notions about what’s true or false. Police officers are no different. The problem is that many officers use their biases to judge suspects, not facts.

Here’s how it works:

  • If a suspect’s words support the officer’s bias, they believe it.
  • If a suspect’s words challenge the officer’s bias, they call it a lie.

This flawed approach gets worse because of how officers are rewarded. They don’t win awards for proving suspects innocent. They’re praised for making arrests and getting convictions. This creates a bias toward guilt—even before the first question is asked.

Remember to Remain Silent

This is why you should always remain silent and not talk to the police. Too often, the police don’t want the truth, they want their biases supported. Remember, never talk to the police, ask for a lawyer, especially if you are innocent.

The Truth About Lie Detection

Police officers aren’t human lie detectors. Science proves that their methods are no more accurate than chance. While officers are an important part of the justice system, they’re not immune to bias.

Knowing your rights and staying silent can make all the difference. If you need help navigating a legal situation, Stone River Law is here for you. Contact us today to schedule a consultation.

Originally Published: November 29, 2024

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