By David Robson
7 September 2015
This story is part of BBC Future’s “Best of 2015” list, the greatest hits of the year. Browse the full list.
How does one go about detecting a liar? One approach would be to focus on body language or eye movements, right? It would have been a bad idea. Study after study has found that attempts – even by trained police officers – to read lies from body language and facial expressions are more often little better than chance. You might as well just flip a coin.
According to one study, just 50 out of 20,000 people managed to make a correct judgement with more than 80% accuracy.
There are other more effective ways to identify the fakers in the vast majority of cases. The secret? To throw away many of the accepted cues to deception and start anew with some startlingly straightforward techniques.
When it comes to spotting liars, the eyes don’t have it.
Most previous work had focused on reading a liar’s intentions via their body language or from their face – blushing cheeks, a nervous laugh, darting eyes. Bill Clinton touching his nose when he denied his affair with Monica Lewinsky is a famous example – taken at the time to be a sure sign he was lying. The belief was that the act of lying provokes emotions – nervousness, guilt, perhaps even exhilaration at the challenge – that trigger unavoidable tiny flickers of movement known as “micro-expressions” that might give the game away. The problem is the huge variety of human behaviour – there is no universal dictionary of body language.
Liar vs liar
It takes one to know one.
Although the techniques will primarily help law enforcement, the same principles might just help you hunt out the liars in your own life. Continue reading the article on BBC.com to find out more.