How To Scientifically Tell When Someone Is Lying

35 How To Scientifically Tell When Someone Is Lying
Men tend to find it more difficult to decipher sarcasm than women. Syda Productions/Shutterstock

Frequently in conversation, people will joke with sarcasm and tell small “white” lies with one another. Normally, most people will find it easy to distinguish when someone is telling the truth, and when someone is simply having a jest, but sometimes the distinction can be fine. People with Alzheimer’s and Parkinson’s, or neurodevelopmental conditions such as autism spectrum disorder, can find this especially difficult. But researchers at McGill University have developed a video inventory to help researchers understand why these difficulties occur, and found out that men tend to have greater problems identifying sarcasm than women.

“We tend to believe that people tell the truth most of the time,” explains Kathrin Rothermich, from McGill's School of Communication Disorders, who co-authored the paper published in PLOS ONE. “So sarcasm and white lies seem to go against a basic understanding of what ‘should’ be happening in conversation. This may be part of what makes them so difficult to recognize for some.”


To discern why people find true intentions during social interactions difficult to understand, Rothermich and her colleague Marc Pell spent two years creating and compiling an inventory of short, scripted (and occasionally awkward) scenes showing two people in various relationships interacting. They then showed these to a group of healthy participants to see if they could ascertain when the characters in the videos were being sincere, when they were joking, and what vocal and facial cues gave it all away.

What they found was that people were usually able to tell when the characters were teasing each other, or when they were telling the truth, but things got a bit trickier when it came to sarcasm. Interestingly, the researchers found that compared with women, men had a harder time understanding when sarcasm was being used. It was only when the characters in the short films were pretending to be two friends that the researchers found that men were better able to pick up on the use of sarcasm.

The videos helped to highlight that it wasn’t simply the tone in which comments were made, but also a mixture of physical cues, such as facial expressions, and even the relationships between the two characters that can give an idea as to whether certain comments are sincere or sarcastic. For example, you’re going to make comments in a different way depending on whether the person you’re talking to is a close friend, a partner, or your boss. Previously, most other studies looking into these forms of social interaction tended to focus solely on the vocal cues.

The researchers hope that this new library of videos, numbering at close to 1,000, will be a useful tool for future researchers looking into social cognition, interpersonal communication and the interpretation of a speaker’s intentions.  


  • tag
  • cognition,

  • social interaction,

  • lying,

  • Autism Spectrum Disorder. sarcasm