The Seductive Allure of Detecting Lies

The July 2, 2007 New Yorker has an extensive article on the development of new lie detection technology based on MRIs. Throughout time, man has tried to develop techniques, both personal and technological, that will reveal when other people are lying. There is an intrinsic appeal to lie detection technology, especially in the justice system, though the accuracy and efficacy of such devices is dubious.

The author of the article points out that one of the many problems with relying on such technology is what we mean by “lying” itself. Self-deceptions, self-justifications, enhancing one’s stature before others; where does truth end and lying begin? And once we make such a determination (is it arbitrary? is it consistent from one person to the next?), should we be comfortable applying such standards in the criminal justice system?

Crimes, from one perspective, are defined completely by society. While certain charges require a showing of intent, even this determination is made by a jury of our peers – we could never take the defendant at his word alone. Ultimately, it is what other people think about a particular action, not what the actor himself intended when acting. Sometimes the most noble of intent will bring criminal charges upon the actor – he may believe what he did was completely justified, but it is behavior that has certain effects that society simply will not permit.

James Surowiecki (relatively) recently published a book called The Wisdom of Crowds. While a simple explanation can’t do the book credit, it details how groups of lay people consistently make a better collective judgment than individual experts: statistically speaking, the judgment of crowds has a whole greater than the sum of its parts.

The application of statistics to criminal justice may not be a proper analogy, but one can’t help but wonder if there is not a similar phenomenon in the judgment of juries. While the individual juror’s judgment may stem from any number of unrelated factors, perhaps as a group juries make better informed decisions. (Side note: a recent study calling into question the accuracy of juries was itself based on subjective measures, such as how often jury decisions are overturned in higher courts.)

In large part, the attractiveness of the perfect lie detector lies in our distrust of the judgment of our fellow man – we have all been duped, and we would like justice to work more cleanly than our common experience. But, we should be careful in getting caught up in the pursuit of the perfect machine: while brain technology can inform, we are woefully uninformed in our ability to pinpoint “truth” in the human mind. While our current system is not infallible, it may be much more effective than we suspect.

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