To spot a liar, ignore everything except the level of detail in a person’s story, new research suggests.
If a person provides rich descriptions of who, what, when, how, and why, it is likely that he is telling the truth. If they overlook these details, they are probably lying.
Using this very simple test and nothing else, people can separate truth from lies with nearly 80 percent 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 you anxious? Why are you restless?
After the 9/11 terrorist attacks, for example, US airport security personnel were trained to look for 92 behavioral clues that a person was cheating. Polygraphs, commonly called lie detectors, combine different physiological data such as blood pressure, heart rate, and respiratory rate to detect possible lies.
However, research shows that even trained professionals do little better than chance when trying to separate the truth from the falsehoods.
Part of the problem is that integrating many conflicting data points on the fly and turning them into a binary decision about whether someone is lying is extremely difficult.
Bruno Verschuere, forensic psychologist and lead author of the study said:
“It’s an impossible task.”
“People can’t evaluate all those signals in a short time, let alone integrate multiple signals into an accurate and truthful judgement.”
Another problem is that people have stereotypes about what innocent and guilty people look like, which are not very predictive of telling the truth or lying.
To overcome these problems, Verschuere and his colleagues at the University of Amsterdam decided to try a “radical alternative”. They instructed study participants to focus on a single clue, the level of detail in a person’s story, and ignore everything else. The researchers say:
“We reason that truth can be found in simplicity and we propose to rule out rather than add clues when trying to detect deception.”
In a series of nine studies, 1,445 people were instructed to guess 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 had staged a mock test theft for a locker and lied about it, or innocently wandered 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 any better than chance.
But those instructed to focus solely on the level of detail in the accounts could accurately separate the truth from the lies with 59 to 79 percent accuracy.
These participants were asked to examine the “extent to which the message included details such as descriptions of people, places, actions, objects, events, and the timing of events” and “the degree to which the message seemed complete, concrete, shocking”. , or rich in detail.” The researchers say:
“Our data shows that relying on one good signal can be more beneficial than using many signals.”
The researchers’ rule of thumb to ‘use the best (and ignore the rest)’ was a superior lie detection method, regardless of whether the participants knew the purpose of the activity was to detect lies or not.
This suggests that pre-existing stereotypes about guilt and innocence did not get in the way of using level of detail as a lie detection tool.
In high-stakes situations, people are likely to enrich lies with details to increase their credibility, so it’s possible that general lie detection rules depend on context, the researchers say.
However, they argue that using more and more clues, or even big data and machine learning, will not necessarily improve lie detection accuracy.
In an earlier study that used 11 different criteria to detect lies, people correctly rated the level of detail, but the other useless information clouded their overall judgment. The researchers say:
“A counterintuitive way to deal with information overload is to simply ignore most of the available information… Sometimes less is more.”
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