How Body Language Lets Us Down

Think you can tell when someone's lying? Think again.

Posted Mar 23, 2014

We love to believe that we can figure out what other people are thinking and feeling without needing to hear a word they say. Those tell-tale eyes that are windows to the soul, that posture that’s a little off, the ever-so-slightly downturned mouth—don’t they all tell us volumes? And if we do listen to words, isn’t the tone just as telling as the content?

Before I became so passionate about the study (and not just the practice) of single life, my area of expertise was the psychology of deceiving and detecting deceit. I even taught a course in nonverbal communication for many years. I know that the idea that nonverbal cues are linked to thoughts and feelings is not entirely bogus—there really can be something there.

The problem is, there's often far less there than we believe.

It is not just ordinary humans who want to believe in the power of body language. The New York Times just posted John Tierney’s article, “At airports, a misplaced faith in body language.” Tierney notes that the federal government poured about $1 billion into training airport personnel to tell if you might be a terrorist just by looking at your nonverbal behaviors as you stand in line waiting to get screened. (I discussed the program here previously.)

The problem with relying on nonverbal behaviors as clues to deception (or as clues to feelings and emotions) is that they are not very strong or very reliable. The always-insightful Maria Hartwig, referring specifically to our pet theories about deception, says that it is a “little more than a cultural fiction” that “liars betray themselves through body language.”

Nicholas Epley, author of Mindwise: How We Understand What Others Think, Believe, Feel, and Want, put it beautifully when he told Tierney, “Body language speaks to us, but only in whispers.”

In the Times article, Tierney discusses the review article I wrote with Charlie Bond, in which we analyzed the deception-detection accuracy of more than 24,000 people who participated in more than 200 studies. The results were bad news for those who would put their faith in humans as lie detectors. On average, people were only correct about determining when people were lying 54 percent of the time. (They'd have been right 50 percent of the time just by guessing.) Ouch.

The impotence of particular clues to deception became glaringly evident when my colleagues and I conducted a similarly comprehensive review of every study ever conducted on particular nonverbal behaviors and whether they might provide evidence that a person is (or is not) lying. In “Cues to Deception,” we did find some cues, but there were very few relative to the number of behaviors we examined, and even those we did find were weak or inconsistent.

Our papers are academic reports, and people reading them who have not spent years in graduate work in the social sciences may not realize something—the results were even more disappointing than they seemed. Consider: When we found that a particular behavior was statistically linked to lying—for example, that liars seem more nervous than truth-tellers—we said that nervousness was a cue to deception. And it was. Across all of the studies that measured nervousness, liars, on average, appeared more nervous than truth-tellers. But here’s the catch: Not all people appear more nervous when they are lying than when they are telling the truth. And not all studies showed that liars appeared more nervous than truth-tellers. The same sobering qualifications are true of other nonverbal cues to deception.

There’s another important way that nonverbal clues let us down: We are unimpressive judges of what our own body language is saying to other people. We sometimes think that when we are feeling sad or annoyed or anxious, that is perfectly obvious to our friends and lovers, when in fact they are clueless. Sometimes—especially with romantic partners—they don’t know how we feel because they don’t want to know. But it is not just their fault. Often our own body language just isn’t that obvious. The signs are not there, even for the people genuinely interested in seeing them.


Want to learn more?

My previous blog posts about nonverbal communication and deception are collected here, including “Why are we so bad at detecting lies,” “Looks can kill—your better judgment,” and “Friends and lovers—is there a ‘knew it all along’ effect?

My review papers on humans’ disappointing ability to know when other people are lying, and on cues to deception, are described in reader-friendly ways in The Hows and Whys of Lies. What we know about serious lies is presented, with lots of real-life stories, in Behind the Door of Deceit: Understanding the Biggest Liars in Our Lives.

If you want the original journal articles, with all the gruesome statistical details, I have put together several collections of those, too. You can find the “Cues to Deception” paper, along with papers on nonverbal behavior and self-presentation, the personalities of liars, and lying in everyday life in The Lies We Tell and the Clues We Miss. The paper on our just-barely-better-than-chance accuracy at detecting deception that Tierney described, as well as the paper showing that federal law enforcement officers are no better than college students at detecting deception (but think they are), and articles on topics such as whether there really are lie-detection “wizards,” can be found in the collection Charlie Bond and I put together, Is Anyone Really Good at Detecting Lies? Professional papers on what friends know and don’t know about us are available in Friendsight: What friends know that others don’t. Happy reading!