To spot a liar, ignore everything but the level of detail in a person’s story, according to new research.
If a person provides detailed descriptions of who, what, when, how, and why, they are likely to be telling the truth. If they skim over these details, they’re probably lying.
Using this very simple test and nothing else, people can separate truth from lies with nearly 80% accuracy, researchers at the University of Amsterdam have found.
When it comes to catching liars, we generally try to use as many telltale signs as possible in our assessment. Do they look sneaky? Are they anxious? Why are they fidgeting?
After the September 11 attacks, for example, US airport security personnel were trained to look for 92 behavioral cues that a person was deceiving. Polygraphscommonly known as lie detectors, combine different physiological inputs such as blood pressure, heart rate and respiratory rate to detect possible lies.
However, Studies show that even trained professionals do little better than chance when trying to separate truth from falsehood.
Part of the problem is that it’s extremely difficult to integrate many conflicting data points on the fly and convert them into a binary decision as to whether someone is telling a lie.
“It’s an impossible task” said Bruno Verschuere, forensic psychologist and lead author of the study.
“People cannot evaluate all of these signals in a short time, let alone integrate multiple signals into an accurate and truthful judgment.”
Another problem is that people have stereotypes about how innocent and guilty people look, which aren’t very predictive of truth or lies.
To overcome these problems, Verschuere and his colleagues at the University of Amsterdam decided to try a “radical alternativeThey asked study participants to focus on a single clue – the level of detail in a person’s story – and ignore everything else.
“We believed that truth could be found in simplicity, and we propose removing rather than adding clues when trying to detect deception,” the researchers said. say.
In a series of nine studies, 1,445 people were tasked with guessing whether handwritten statements, video transcripts, video interviews, or live interviews about a student’s activities on campus were true or false.
These accounts came from students who either faked stealing an exam for a locker and lied about it, or innocently wandered around campus and told the truth about their activities.
Study participants who relied on intuition to detect lies, or who used many factors to make the decision, did not perform better than chance.
But those instructed to focus only on the level of detail of accounts could accurately separate truth and lies with 59-79% accuracy.
These participants were said to examine the “extent to which the message includes details such as descriptions of people, places, actions, objects, events and the timing of events”, and “the extent to which the message seems complete, concrete, striking or rich in detail”.
“Our data shows that relying on a single good signal may be more beneficial than using many signals,” the researchers said. say.
The researchers’ rule of thumb “use the best (and ignore the rest)” was a superior method of lie detection, whether or not participants knew the purpose of the activity was to detect lies.
This suggests that pre-existing stereotypes about guilt and innocence did not preclude the use of level of detail as a lie detection tool.
In high-stakes situations, people are likely to enrich lies with details to increase credibility, so rules of thumb for detecting lies may be context-dependent, researchers say.
However, by using more and more indices – or even big data and machine learning – will not necessarily improve the accuracy of lie detection, they argue.
In a previous study Using 11 different criteria to detect lies, people correctly rated the level of detail, but the other unnecessary information clouded their overall judgment.
“A counter-intuitive way to deal with information overload is to simply ignore most of the available information…Sometimes less is more,” the researchers say.
This article was published in Nature Human behavior.