Lying takes mental effort. It’s harder to remember made up facts than real ones. According to University of Texas researchers that can give you four clues to tell if someone is lying.

  • Faulty memory. When Bill Clinton was asked about his relationship with Monica Lewinsky he frequently mentioned not being able to remember. Now we know that had nothing to do with early on set dementia, it’s a common defence to prevent a liar from being caught out.
  • Contradictions and corrections. Making up a plausible story is not always as easy as it seems. Subtle or not so subtle contradictions and modifications will often creep in.
  • If they’re struggling to communicate it may mean they’re being over loaded by the mental effort of fabricating a believable story.
  • The fear of getting caught out is likely to raise their stress levels – unless they’re a psychopath. (More on those in a future episode.)

So if they claim amnesia, trip over their words, sweat bricks and the story keeps changing, that might be because … it’s just a story.