After watching lots of movies and TV shows, many people believe they have the skills to catch a liar in the act. At least, that’s what they would like to think.
Research shows that the average person’s accuracy in detecting deception from a conversation is about 54 percent. (Source: Bond and DePaulo, 2006.) That being the case, if you rely on your human lie detection skills, you’ll get it right about half of the time. That’s about as good a coin toss.
Incidentally, the same research shows that training does not tend to increase the accuracy of a human lie detector.
Is there such thing as typical liar behavior?
Let’s divide this into two categories:
- Non-verbal: body and eye movements, vocal behavior and facial expressions
- Verbal behavior: speech patterns such as word choice, grammar, errors, rate and voice pitch
Do liars exhibit typical non-verbal behaviors that can be monitored?
Do liars avoid eye contact, tap a foot or finger, use their hands more to express themselves, shift their body, or blink more? One study showed that most people share the belief that liars exhibit these non-verbal behaviors and probably because they are nervous. (Source: Vrij, 2008)
Well, the same study showed that liars tend to maintain normal eye contact, hold their feet and fingers still, do not shift their bodies more than normal, and blink normally. Also, liars and truth tellers tend to move their heads and smile about the same amount.
In fact, because of the increase in cognitive load required to tell a good fib, liars tend to hold their arms, hands and feet very still. They hold still because their cognitive effort is focused on spinning a good tale.
Do liars exhibit typical verbal behaviors that can be observed?
Do liars hesitate more, make more speech errors, increase their voice pitch and pause more? You might think so because, again, the common belief is that liars are nervous and nervousness causes these verbal ‘errors.’
Contrary to these assumptions, the study showed that liars do not hesitate more or make more speech errors or pause more frequently. Their voice pitch can increase slightly, but most of the time that change is so minute, the human ear cannot detect the change. Liars tend to increase the duration of their pauses and they do tend to increase latency (speak more slowly).
Also, contrary to common belief, liars do not necessarily look nervous. Some skilled liars can even appear to be very calm and collected. Sociopaths may also not appear anxious. So, you should not rely on nervous ticks as lie signs. Truthful people get nervous too.
What can you do to detect a liar?
There is not a one-size-fits-all response to this question, but there are some common behaviors that most liars exhibit in verbal content. In other words, it’s not how they say it or how they act, but what they say.
The same study by Vrij showed that when fabricating a story, liars tend to make more negative statements—such as speaking negatively about other people involved, or the situation at hand, or to deflect the questions from the interrogator.
Liars tend to distance themselves from the story or from others. Remember the famous line, “I…did…not …have…sex…with…that…woman?” We know that this famous person knew the name of “that woman” but chose to distance himself from her.
Liars tend to give shorter responses to questions. This may be due in part to the fact that liars tend to memorize the ‘story’ in bullet points or short sequences. They may not consider a lot of detail when coming up with a fib. But because the story is memorized, it may be easier to repeat the story in the same way, over and over.
One good way to trip up a liar is to ask them to repeat their narrative in reverse order. Most liars don’t plan out and memorize their story from Z to A.
Also, when spinning a yarn, liars tend to give contradictory details or say things that are not plausible in terms of time lines and event sequences.
So now what?
In short, when interacting with others and you believe you’re being sold a bill of goods, don’t watch for body, head, or eye movements. Don’t look for finger or foot tapping or fidgeting. Don’t listen for speech errors, pitch changes, or hesitations. The best thing to do is to listen to what is said. This is a good exercise and can help uncover lies. If anything, it can improve your interrogation skills.
But remember, research shows that the average person’s accuracy in detecting deception from a conversation is about 54 percent.
Note: This article and the opinions expressed here are from Russ Warner, VP of Marketing at Converus, makers of EyeDetect, an innovative, new lie detection solution.