Credibility is a fraught issue these days. Playing out in one courtroom is the debacle of the discredited accuser in the Dominique Strauss-Kahn case. In another is the Casey Anthony trial with its holiday parade of potential liars. Maybe you are confident that you are a terrific lie detector -- you are sure you can separate the trustworthy from the slime. Surprise! More than a dozen studies have shown that there is no link between confidence and skill. If you think you are a great human lie detector, you are no more or less likely to actually be great than if you think you are a terrible lie detector.
In my decades of doing research on deception and studying the work of others, I've found a whole raft of ways our judgments of credibility can go astray. Here's a sampling.
- Looks can kill -- your better judgment. Some people have a certain "look" or manner about them. The lucky ones just seem honest and trustworthy all the time, even when they are lying. The less fortunate ones characteristically come across as untrustworthy, even when they are telling the truth. If you truly are a discerning lie detector, you should not be fooled by a person's characteristic look. Instead, you should be able to tell in any particular instance whether that person is lying or telling the truth. So can you? If you are an ordinary person, with no special experience or training in the detection of deception, the answer is no. Faced with a person whose typical look is inconsistent with their actual truthfulness, you are more likely to go with the look. But what if you work in a government security and intelligence agency, you have had formal training in the detection of deception and you have more than 14 years of on-the-job experience trying to detect lies? If a person's characteristic look is consistent with their truthfulness, you will be unbeatable. But if the look is inconsistent, you will do worse than college students and worse than fellow agents with far less experience. Check out the stunningly-poor accuracy scores and read more about the studies by Tim Levine, in this post.)
- Love can blind you. The romantically involved like to think that they, more so than anyone else, know when their partner is lying. And why not? Many couples do spend a tremendous amount of time with each other. Well here's why not: You don't want to think that your partner is lying, especially not to you! In a clever dissertation described briefly here, Eric Anderson asked one member of each of 100 couples the dreaded question, "Do you think that person over there is attractive?" Who was best at recognizing when the person was lying -- the person's partner or a complete stranger? Okay, I set you up for that. The answer is a complete stranger.
- Imitation may be flattering, but it doesn't make you a better lie detector. Have you noticed how two people sometimes seem totally in sync as they interact with each other? One person is tilting her head, and the other seems to be mirroring that movement. Facial expressions, speech rates and patterns and even accents are also subject to this sort of mimicking, which most of the time is probably unconscious. In many ways, mimicking is a good thing -- people who mirror each other's movements often feel closer and more understood. But they are actually worse at knowing whether the other person is lying or telling the truth. The research by Marielle Stel and her colleagues is here.
- Be happy, get duped. It is nice to be in a good mood. Who wants to be a crank or a Debbie Downer? When it comes to ferreting out liars, though, Debbie rules. People who are in a bad mood are more skeptical of others. In some ways, they are also more accurate at separating the liars from the truth-tellers. The research by Joseph Forgas and Rebekah East is here.
- For years, my colleagues and I collected people's stories of the most serious lies in their lives, described here. Our sense was that they did not fully appreciate the extent to which their own qualities tempted other people to lie to them. Often, those qualities that attracted lies were very positive ones. People who are beautiful, graceful, charming and sexy are often the targets of lies told by others who are trying to impress them. People with power and authority elicit lies, too. That may seem obvious in the abstract, but when you are the person hearing how wonderful you are, you may find it more comforting to believe that your flatterers are truthful and wise, than to realize that they are just shameless sycophants.