The Backwards Lying Trap

Is he (or she) lying? There are numerous clues that can help you spot a lie. You can learn about body language and how words are used, and even how to trap a liar. But one of the more interesting ways to tell if someone is lying comes from recent research at the University of Portsmouth. It has to do with our difficulty telling a story backwards.

Researchers started with the general theory that it is harder to invent a story than to tell a true one. This makes sense. If someone asked you what you did last night, you would be able to remember and recount the events quickly, right? It might take you a little more time to invent a story.

Starting from this, they decided to test to see what happens when people try to relate events in reverse order after first doing so in chronological order. Naturally it is harder, but most of us have no problem doing this: "I came home. Just before that I was at the convenience store, and before that at the bar on fifth street." However, would it be more difficult to do this if the story was invented? Would you make more mistakes and change your story?

This is exactly what the testing indicated. It included 290 police officers, and 255 students. The police officers were supposed to determine whether the student in each interview was lying or telling the truth (students were prepped beforehand to do one or the other). Regular police interview methods were used, and then "cognitive load interviews" were tried, in which the "suspects" were asked to recall the most recent events and work backwards.

The results? Officers were much more likely to determine who was lying when these "reverse tactics" were used. "Those paying attention to visual cues proved significantly worse at distinguishing liars from those telling the truth than those looking for speech-related cues," said researcher Aldert Vrij. "Certain visual behaviors are associated with lying, but this doesn't always work. Nor is comparing a suspect's responses during small talk, and then in a formal interview, likely to be much help."

Vrij also noted that unlike those telling the truth, "...liars tend to tell their stories in a strict chronological time order..." That's another little clue we can use to tell if someone is lying. But the primary lesson here is that liars have a harder time keeping their stories straight when they have to tell them backwards.