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Can You Spot a Lie?

How good are we really at detecting lies?

Key points

  • Research shows that people are no better than 50-50 at detecting lies. 
  • People often make an assumption of truth with those they care about.
  • It is best to assume that our body language-reading skills are only average, and instead ask questions designed to get the person to admit a lie.

How good are you at spotting a liar? Most people think they are above average, but the research clearly shows that we are no better than 50-50—a flip of the coin, pure chance—at detecting lies. We may be better at spotting the lies of someone we know well, at least we’d like to be, but again there’s no evidence to support this, just a pious wish.

There’s an assumption in my question that the way you spot a liar is to detect something in the non-verbal behavior that gives away the lie. The words say one thing, the body language another. And when those two "conversations" are at variance, we always believe the body language. When you ask your partner if she’s upset about something, you don’t spend a lot of time parsing the words “I’m fine”; rather, you listen for the tone of voice, look for the folded arms, and so on, to see what the non-verbal conversation is telling you. If all of that is negative, you assume she’s not fine.

There’s nothing particularly remarkable about this behavior. We all spend a fair amount of time detecting how people around us feel by the clues they send us through body language, and quickly determine what we think their real intent is.

Source: Thirdman/Pexels

And given how important intent is to human conversations and connections, you’d think we’d be better at determining it in general. That there is a practically foolproof way to detect a lie in particular, then, comes as a bit of a surprise. And it has nothing to do with body language.

It’s known as the Reid Technique, after the former Chicago police officer and psychologist who developed it. His first famous conviction was overturned when the man that Reid got to confess turned out to be innocent (another person confessed), but the technique was established and it is still in use.

The technique doesn’t use body language at all. Rather, it involves assuming that the person under suspicion is guilty and asks a series of questions designed to lull the apparent perpetrator into feeling that the questioner is on his or her side. “Did you plan this or did it just happen?”

Not a good technique to use on those near and dear to us, because its greatest weakness is that it leads to false confessions, and presumably asking a long series of questions about the incident that your loved one is denying would not feel like a relational way to act. The real reason that we are not very good at determining lies and liars is that we make an assumption of truth with the people we love, most of the time—and that’s a good thing. Most of us do tell the truth most of the time about the stuff that matters in our lives, and that’s how human intimacy and trust are supposed to work. Little white lies (“no, that doesn’t make you look fat!”) are the roadkill on the highway of truth, the road we all want to be on.

That does make us vulnerable to lies, but it is still a better way to operate than to assume everyone is lying to us all the time. That would cause way too much friction in our relationships.

Is there anything that we can take away from the Reid Technique that is useful in our everyday lives, and that would increase our ability to spot lies when it matters? Just this: assume that our body language-reading skills are only average, and instead ask a question or two designed to allow the party in question more easily to admit to the lie. The questions should assume guilt and then ask how it felt. “Was it fun to hide the empty brownie pan?” Listen hard to the answer and what it may tell you. And don’t expect very much. We’re better off being occasionally fooled than eternally suspicious.