Why You Are Bad At Spotting Liars

Do you consider yourself a good judge of character? Do you believe you can identify when someone is lying to you? And if not, do you think that professionals like law enforcement or psychiatrists are any better? You are mistaken. As it turns out, most humans are terrible at identifying whether someone lies to them. And it is a good thing.

In Talking to Strangers, Malcolm Gladwell discusses a test done by economist Sendhil Mullainathan and his team. They have gathered records of 554,689 defendants brought before New York courts from 2008 to 2013. They have found that judges released 400,000 of them in arraignment hearings. Mullainathan tried to answer whether a computer, an artificial intelligence, could do a better job than human judges in predicting who will not commit crimes and can be therefore released on bail. He fed the computer the same data judges had and compared results with what happened. As it turns out, the computer beat the judges by a considerable margin. The 400,000 people on the list compiled by computer for release were 25% less likely to commit a crime while awaiting the trial than the list of 400,000 released by judges. The conclusion is clear. Human judges don’t do particularly well when trying to assess who is honest and who is lying. As it turns out, most of us are not good at it.

Truth-default theory

Gladwell points to the research by numerous psychologists, including Timothy R. Levin, who coined the term truth-default theory. Experiments have shown that people are terrible at judging whether someone speaks the truth or lies. In Levin’s experiments, the participants were able to spot liars only 54% of the time. It included even those you would expect to be good at it, like police officers, judges, or therapists. As Levin postulates, the culprit seems to be our preference to default to the truth. If someone lies to us, and even if we see some signs that they may not speak the truth, we still prefer to believe them. Deep inside, we are wired to assume that people who talk to us tell the truth.

There are exceptions, though. Certain individuals don’t default to the truth. Throughout history, these people would see the liars and conmen everywhere. They would be paranoid and voice their paranoia. They would be allowed to speak their truth. And others wouldn’t listen. Society needs a couple of people like this to point out what the rest of us don’t see or don’t want to see. However, we can’t all be like this as it would be the end of civilization. As Malcolm Gladwell points out, evolution didn’t give us the ability to detect lies because, in the grand scheme of things, there is no significant advantage in spending time trying to decipher whether someone is lying to us. Better is to assume that people are generally truthful and move on with our lives. It allows us to build relationships, make friends, and keep us together as a group. We may be deceived every now and then, but that is a small price to pay for keeping society together. Efficient communication and collaboration not inhibited by paranoia is much more beneficial.

Facial expressions across cultures

Human evolution gave us one way to find out how others feel—the ability to read facial expressions. You can look at someone, and based on whether they are smiling or frowning, you can deduce how they feel. It is so intuitive. You may not know me, but based on how I look, you can understand what I feel even if you don’t understand my language or culture. Or can you?

Gladwell points to studies of tribes in the Trobriands islands east of Papua New Guinea. It is a completely isolated home of around 40,000 people. Anthropologists who studied the tribes found out something surprising. When shown pictures of smiling or sad faces and asked to identify which showed happiness, sadness, anger, fear, and disgust, they utterly failed. Compared to Spanish participants of the study who could guess correctly in the vast majority of the cases, Trobrianders did significantly worse. For example, 100% of Spanish children in the study identified face showing happiness as happiness. However, only 58% of Trobrianders did the same. What may be the sign of being scared in one culture might be a sign of aggression in another one. We can’t rely on reading someone’s emotional state just by looking at their face.

This has an unfortunate implication for our judges from the beginning of the article. Human judges would in their rulings consider whether someone “shows remorse.” But how do you know what remorse looks like for a particular person? You don’t. Therefore assuming that someone is not remorseful only because they don’t look sad and lower their heads doesn’t work. When judges see the defendants, they can easily misread the body language. Their ruling is less fair and more biased compared to the algorithm. In fact, if the judges wouldn’t see the defendants, they would make better decisions.

We believe that people are transparent and that their thoughts reflect in their body language, facial expressions, and demeanor. If you are confident, well-spoken, you have a firm handshake, and you look me in the eye, I will judge you as honest. If you are nervous, you won’t look me in the eye, and can’t express yourself, I will assume you have something to hide. Unfortunately, that is not how things work. But we behave like it is true anyway.

Torture doesn’t work

Even those who are paid to get the truth out of others run into limits imposed by nature. Most forms of interrogation and torture don’t work. Things like sleep deprivation, putting people through intense stress, and abuse have a significant adverse effect on people’s brains. You may believe that you finally broke the person when they start talking, but the reality is that what you have done is shut down their prefrontal cortex. Their memory gets significantly impaired. You can’t believe anything they are saying. It is not because they would lie on purpose, but because under a considerable level of stress their brains are incapable of providing the correct answers. In a rather controversial set of experiments, Charles A. Morgan ran various tests with special operations soldiers. He would put them through extreme stress and found out that their answers were extremely unreliable even when they did their best and tried to be truthful.

Putting it all together

So how do you know whether someone lies to you? You don’t. And that is okay. Use the truth-default setting that nature programmed you with and learn to trust people. It will help you build stronger relationships faster. Give others the benefit of the doubt.

That being said, learn from your mistakes. If someone lies to you or cheats you, it is unfortunate. Still, it probably couldn’t be prevented without a ton of paranoia and a negative impact on how you approach the world. However, don’t let others keep taking advantage of you. As the saying goes, “fool me once shame on you, fool me twice shame on me.”

Do you agree? What are your thoughts on the topic? Do you believe you can tell whether someone lies to you? Do you consider yourself to be a trusting person? Do you believe it is better to be trusting or paranoid?

Photo: geralt / Pixabay.com

Follow me on Twitter: @GeekyLeader

Categories: Life

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1 reply


  1. Why Emotional Intelligence Doesn’t Always Work – The Geeky Leader

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