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The Only Way to Really Detect When Someone Is Lying

Most attempts to detect liars fail because people look for entirely wrong cues.

Ame Otoko/ Creative Commons
Source: Ame Otoko/ Creative Commons

How can you tell when someone is lying? If you Google this question, you will find that there are mountains of books, an endless supply of youtube videos, and thousands of blogs and articles ready to provide the answers. Sadly, a quick perusal of these sources reveals that they are loaded with claims that have little or no basis in reality. They suggest that the direction of a person’s gaze, avoiding eye contact, fidgeting, microexpressions, voice pitch, and many other cues can tell you whether a person is being honest or is trying to deceive you. The authors of these pieces offer to help you become an expert lie detector, sometimes for a modest fee.

There is one important fact that these sources seem to ignore. There simply are no behavioral cues that reliably indicate when someone is lying. Researchers like myself have searched high and low for such cues for decades. The best anyone has come up with is a small number of behavioral cues that are extremely unreliable. The simple truth that is ignored by the many purveyors of lie detection tips is that there just aren’t any solid cues to deception such as a nose that grows longer when someone is lying.

When provided with extensive training in detecting deceit, people typically do improve and become more effective lie detectors. The problem is that most people start off performing only slightly better than chance. That is, they are not really much better than random guessing. What that means is that the “improvement” that training confers in lie detection brings people from near chance levels of detection to a bit better than chance- a far cry from the expert lie detectors we are promised we can become.

How Liars Lie

Why can’t we easily detect liars? It turns out that people are just very good at concealing their lies. As children, we all learn that it is quite easy to simply look normal when telling an untruth. We just look people in the eye, and with a warm smile on our face, just lie. And just like that, we easily deceive people. Nobody has any idea.

How to Really Detect Liars

But don’t abandon all hope just yet! There actually are some fairly effective ways to really detect liars. The trick is to abstain from useless attempts to read body language and facial cues. We must look for something else. Something more dependable. We much search for the real evidence. The trick, as it turns out, is to listen and pay attention. Lying is nothing more than communicating false information. Listen to that information. Does it make sense? Does it align with other information we already have? If not, it might be time to move on to the next stage of lie detection- probing. If someone’s story sounds a little off, start asking questions. Test the story. Does it stand up to scrutiny? Are the answers evasive? Does the story begin to shift as if constructed on a foundation of quicksand? These are valid cues that the story may be a lie. The last step is to verify. If the story involves claims about who, where, what, and when, they can often be corroborated if true. If a lover says they were at a family event, family members should be able to readily verify the alibi. If an employee claims to have been hospitalized, they should be able to easily supply documentation. The last key is to ask the person to come clean. Surprisingly, when many liars are politely and sympathetically asked to tell the truth, they comply and offer their confession.

One study examined how people actually caught liars in their day-to-day lives. It turned out that only about 2 percent of people said that verbal or non-verbal cues help them root out the liars. Instead, the most frequently reported methods were information from third parties (e.g., an alibi that just doesn’t come through), physical evidence (e.g., receipts, phone records, and credit card bills), and solicited confessions.

P. Valdevieso/ Creative Commons
Source: P. Valdevieso/ Creative Commons

How can you really detect liars? Stop searching for useless cues such as body language and start paying careful attention to what is said. Like a detective, investigate those claims to see if they actually align with evidence in the world. Turn the screws. Liars do often give themselves away, but they do it with their words, not their body language.

Facebook image: CREATISTA/Shutterstock


Park, H.S., Levine, T., McCornack, S., Morrison, K., & Ferrara, M. (2002) How people really detect lies. Communication Mongraphs, 69(2), 144-157.

Levine, T. R. (2019). Duped: Truth-default theory and the social science of lying and deception. University of Alabama Press.

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