How do you spot a liar – no, it’s not body language

Lying is part of life: we all lie several times a day, and probably neither our society nor we ourselves would stand it if everyone always told the truth. There are more innocent lies, such as to avoid hurting someone else, but some lies are serious and can have serious consequences. Anyway, lying has a bad reputation. And no one wants to be lied to. The question is therefore probably as old as humanity: how do you find out if someone is lying?

There are several approaches to answering this question: Some swear by meaningful body language. Thus, it is considered an indication that someone is lying if this person often touches their nose. Then there are technical procedures such as the lie detector, which can detect signals such as an accelerated heartbeat or muscle spasms.

Of course, you rarely have a lie detector handy and this device cannot determine whether bodily signals really occur from lying or for some other reason, such as stress. Recognizing and correctly interpreting the many physical signs of lying is anything but easy, says Bruno Verschuere, associate professor of forensic psychology at the University of Amsterdam (UvA). The same goes for people whose job it is to spot liars: since the attacks of September 11, 2001, security personnel in the US have been trained to recognize up to 92 different signals.

“It’s nonsensical, because it’s an impossible task. People can’t evaluate all those signals in a short time, let alone integrate multiple signals into an accurate, truthful judgment,” explains Verschuere in a press release from the university. The behavioral researcher , who leads the LieLab at the UvA, has developed a new approach to expose lies together with scientists from Maastricht and Tilburg.The corresponding study was published in the scientific journal “Nature”.

Verbal lie tests, that is, the analysis of what was actually said, usually try to combine a wide variety of signals — such as the consistency, immediacy, and credibility of the story, says Verschuere. But these signals almost never all point in the same direction, and trying to take them all into account in a conversation with a would-be liar is bound to lose perspective. Verschuere and his team, on the other hand, focus on one signal that serves as a criterion for assessing the veracity of a story: the level of detail.

So as a listener, you should only focus on the amount of detail in the would-be liar’s story. That takes some getting used to, admits Verschuere, but it works very well. “It feels very counterintuitive to just listen to what people are saying and not pay attention to all sorts of other clues, like how convincing or emotional someone is telling their story. But people who tell the truth can give a detailed description because they actually experienced the event. Liars can make up details, but that increases the chance of being caught,” he explains.

While crafty liars can easily fake emotions and control body language, it is much more difficult for them to go into detail in their untrue story.

The LieLab team conducted a series of experiments to test their hypothesis. First, the students were divided into a group of “guilty” and a group of “innocent”. The perpetrators were instructed to steal an exam from a locker. The innocent, on the other hand, have to stay on campus, go to the library, have a coffee and call a friend. Then both groups had to say that they had been on campus for half an hour.

The subjects, totaling 1445 participants, were asked in a total of nine studies to rate the veracity of the handwritten statements, video transcripts, video interviews or live interviews. The subjects were also divided into two groups: one was instructed to pay only attention to the amount of detail (place, person, time, place) in the speaker’s narration, while the control group was free to use any cues possible, like body language. , Use nervousness or emotionality for the assessment.

The result: While the control group achieved a success rate barely above chance level, the group that only pays attention to the details performed significantly better. So if you don’t quite trust a story presented to you, you should pay attention to the details that are there – or rather, the lack of them.

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