Last year, I was assisting a trial lawyer with jury selection. After the voir dire, we caucused to discuss our strikes. This lawyer vehemently insisted that one of the jurors was lying and had to be struck. He knew in his gut that the juror had lied and there was no way he was going to keep her on the jury. She went, and we will never know whether or not she was telling the truth.

Is it possible to tell if a juror is lying? Over the years, a great deal of psychological research has been conducted to see if there are behaviors that correlate with lying. To very briefly summarize this research, the following behaviors have been found to be associated with deception: – Vocal behaviors: A raise in the pitch of the speaker's voice, decrease in rate of articulation, hesitation in speaking, and brief responses. – Micro expressions: Brief head shaking, decreased or increased eye contact, breaking eye contact by interfering body movements (like adjusting one's glasses), the covering of one's mouth, or briefly covering one's face. – Body posture: A rigid and generally frozen posture and/or a defensive posture (backward lean, arm crossing, and leg crossing).

This would make it appear relatively easy to detect deception, but the evidence from a number of studies points in exactly the opposite direction. In 1999, Paul Ekman and Maureen O'Sullivan published the results of one seminal study, "Who Can Catch a Liar", in the American Psychologist (Vol. 46, No. 9, 913-920). They recruited 509 people and tested their ability to detect people lying. Among their subjects were members of the CIA, FBI, DEA, NSA, and the Secret Service as well as professional polygraphists, judges and psychiatrists. The sample did not include jury consultants. One might expect that these people more than anyone would be able to figure out who was lying (for as the authors describe them, they are "professional lie catchers"). They were each shown videotapes of ten people in which half the people were lying and half were telling the truth. Only the Secret Service agents performed significantly better than chance in pointing who the liars. Even these agents classified some liars as truth tellers and vice versa. All the other subject groups performed no better or worse than chance. Ekman and O'Sullivan hypothesize that the Secret Service agents were trained to pay more attention to subtle facial expressions—that, in fact, there are some special people who may be better at detecting deception than others. However, Ekman, O'Sullivan and other researchers have found additional "buts":

There is no relationship between a person's confidence in her ability to detect lying and her actual ability. – There is some evidence that those who are more experienced are less able to detect lying than novices. – Many of the behavioral traits associated with lying are also associated with anxiety; a feeling many honest jurors have during voir dire. – It is easier to detect deception over time in a controlled setting (not in a courtroom). – And, some people are better at lying than others. After all, people are more practiced at deceiving than in detecting deception.

So where does this leave the trial attorney? Beware consultants who tell you they can pick out jurors who are lying (however confident they are); question your gut instincts; stick with the profiles you have developed; and, most importantly, stick with the evidential story you will tell. Or, you could hire a Secret Service agent.