You Can't Judge A Liar By His Face

A fundamental proposition of American law, that observing a witness is key to determining if the witness is telling the truth, is empirically wrong:

It is largely a myth, however, that judges, or anyone else, can reliably differentiate between honesty and mendacity simply by picking up visual cues. Studies have consistently shown an extremely high error rate in recognizing deception, even among professionals who pride themselves on the ability to weed out deceit. One set of tests, for example, was given to judges, police officers, trial lawyers, psychotherapists, CIA agents, and customs examiners, and no group was able to identify liars at a rate better than 50 percent. . . .

There is, however, one exception to the rule . . . Successful professional poker players can, and do, accurately read their opponents' intentions, figuring out when they are bluffing, when they are holding winning cards, and exactly what it will take to sucker them into losing bets.

Some of the great poker mavens have revealed their secret techniques for identifying "tells," . . . [but] it is nearly impossible to pick up a reliable tell on the basis of a first impression. . . . it is crucial "in discovering tells . . . for a player to develop a sense of the baseline behavioral repertoire of one's opponents." That simply can't happen in the compressed time frame of a small claims trial.

Moreover, poker games-unlike trials-provide repeated opportunities to validate one's interpretation of tells. If you suspect that an opponent is inadvertently signaling a bluff, well, all you have to do is call the bet to find out. Over a series of hands, therefore, you can pretty much determine whether your intuition is accurate. In contrast, a judge's credibility conclusion is self-fulfilling, a onetime decision with neither a baseline nor a reliable means of external verification. There is no equivalent to showing the actual cards, so suspected liars just lose their cases, and that's that.

Why is this important? Because appellate deferrence given to juries and judges who make determinations of fact at trial, in an age where we have accurate verbatim records of the proceedings, is largely based upon the fig leaf that they are better able to judge the credibility of the witnesses. If this isn't true, the implication is that the law should give appellate judges greater freedom to overrule trial results on the basis that the trial court got the facts wrong.