The truth about lies: what does research tell us about deception?

This post is also available in Dutch.

Without a doubt, lying is an inconvenient, though inevitable, part of human existence. This blog will tell you what we know about lies and how we can spot them.

Is someone lying or telling the truth? There are moments in our lives when we are faced with this question. When the suspicion arises, we wonder even more: How can we decipher truths from lies? A popular belief is that you have to look at a person’s face to see if they are lying. Supposedly, microexpressions (facial movements that last less than a fraction of a second) help in identifying lies. This idea about the utility of microexpressions has been popularized by TV series like Lie to Me, which drew inspiration from the work of American psychologist Paul Ekman. Some of Ekman’s ideas, including those about how facial movements are representative of one’s internal state, have been recently questioned by other scientists. While we often try to read someone’s face to discern what they feel, this “reading” mainly hinges on our interpretations and best guesses based on the context. So what do we actually know about lying?

We lie little, and we are not good at detecting it

The vast majority of people tell lies very seldomly. Most lies, as shown by researchers in the USA and the Netherlands, are told by a very small fraction of the population (i.e., “prolific liars”). As shown in the graph below, 40% of lies were told by only 5% of people.

Illustration from Serota et al. (2010)

We also know that people, including professionals like police officers, judges, or social workers, are bad at spotting lies. Imagine if I showed you a set of 44 videos with an equal number of liars and truth tellers: you would only be able to tell who is lying with 56% accuracy. Such experiments have been conducted by Timothy Levin, who has numerous studies on deception. A meta-analysis that synthesized the results of many studies of people’s abilities to identify lies similarly shows that people are a bit better than chance, with a 54% accuracy, so just 4% better than tossing a coin.

The explanation given by researchers for our poor ability at detecting lies is called the default to truth (or truth bias). In this sense, our communication with others benefits from believing in others rather than being suspicious of them. Communication would be very inefficient if we had to question constantly how believable someone’s story was. Evolutionary psychology claims that deception and communication co-evolved. Yet, at the same time, cultures developed mechanisms to discourage individuals from lying. Think about every major religion that teaches us that lying is a sin, and modern societies wherein providing false information is lawfully punishable.

So how can we be more certain that someone is lying?

Research on deception suggests that there is a more reliable way to spot a liar than looking at the facial expressions celebrated by Paul Ekman: Asking the “hows” of stories we are told, or “paralinguistic cues” as scientists like to say. A meta-analysis shows that someone who lies tends to have a higher pitch in their speech and takes more time than usual to begin a sentence, exceeding the 200 millisecond pause of silence defined by Psycholinguistics research.

While we all are bad at detecting lies, the bright side is that most people tell the truth most of the time. But if you do, after all, get suspicious that someone is not being honest, then listen to how they speak. Chances are that the “hows” of language will be more useful in determining what’s what, rather than other non-verbal cues like microexpressions.

Original language: English
Author: Julija Vaitonyte
Buddy: João Guimarães
Editor: Christienne Gonzales Damatac
Translator: Felix Klaassen
Editor translation: Wessel Hieselaar

Featured image by Republica via Pixabay

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