Catching Liars.

Abstract

While trying to think of an interesting way to introduce this major review of the field of lie detection, I did what lots of people do these days. I typed ‘‘catching liars’’ into the Google search bar and up came 305,000 results in .17 seconds. The first page was ‘‘10 ways to catch a liar’’ from WebMD. The essay featured J.J. Newberry, a trained federal agent purported to be skilled at detecting deception in people he interviewed. One of his success stories was the lie he spotted when a witness to a shooting tried to tell him that she heard gunshots and, without looking, just ran away. Newberry was suspicious: For him, this was inconsistent with how people respond to situations like this. And to prove his point, he banged on the table and the witness instantly looked right at him. This story helped motivate the tip at the top of the list for catching liars. The number-1 tip, Newberry said, is to look for inconsistencies in what witnesses are saying. Number 2: Ask the unexpected. Newberry’s professional experience and notions about liars would find some support in the following Psychological Science in the Public Interest article on lie detection. But I expect that he would also find out some new things that might surprise him. The focus of the article is on behaviors, both nonverbal and speech behaviors, that can be used by someone who wants to try to detect deception in another person. Basically, we’re not particularly good at detecting deception, for a number of reasons. First, we often don’t want to catch lies: We’d rather be happily in the dark about some matters. Second, detecting lies is not that easy to do. We make mistakes because we rely on behaviors that aren’t helpful and that can even lead us astray. We expect liars to behave in certain ways, but they don’t. We think that liars look away (gaze aversion) and that they fidget (grooming gestures). These popular cues that people use to detect lies are not reliable cues. How do we know this? Researchers on lie detection have devised some very clever ways of trying to figure out what liars actually do. For years, experimental subjects have been instructed to lie or to tell the truth about some matter. For example, they lie about a film they recently saw or about whether they had a particular object in their pocket. Or, more complexly, they go to a restaurant to have lunch (the truth) or they commit a mock crime and pretend they were at the restaurant having lunch (the lie). Or they are passengers at an airport who either tell the truth about an upcoming trip or tell a lie. Liars don’t look away, and they don’t fidget more than truth tellers do. Using gaze aversion to decide that someone is lying can be dangerous for that someone’s health and happiness. And— what was news to me—some cultural or ethnic groups are more likely to show gaze aversion. For example, Blacks are particularly likely to show gaze aversion. So imagine now the problem that might arise when a White police officer interviews a Black suspect and interprets the gaze aversion as evidence of lying. This material needs to be put in the hands of interviewers to prevent this kind of cross-racial misinterpretation. But all is not hopeless for catching liars, since happily some speech cues are more diagnostic of deception than nonverbal cues are. The authors recommend an ‘‘information gathering’’ approach to interviewing (rather than an accusatory approach). This type of interview will result in more information being gathered than can later be checked for inconsistencies against other available evidence. The authors also recommend asking unanticipated questions. A witness who claims to have been eating lunch at a restaurant might be asked, ‘‘Who finished their meal first?’’ Liars are apparently less likely to say ‘‘I don’t know’’ to unanticipated questions and to offer some answer, possibly because they are afraid that to do otherwise would look suspicious. One challenge for the lie detection field is only hinted at in the current article. The authors argue that people with a powerful imagination and the ability to believe in their own lies will not experience guilt or fear or emotions that might be associated with lying. Some people can develop a false belief in their original lies—and so, in essence, are not lying at all. This problem is nicely illustrated in some recent work from Maastricht University in the Netherlands on ‘‘self-fulfilling fakery’’ (Merckelbach et al., 2010). In this research, some people were instructed to malinger (to lie about their symptoms—for example, to claim they had more trouble concentrating than they actually did). Later, these people had to report their symptoms