Don’t Make That Face

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Could a computer soon read your facial expressions, decide that you’re lying, and testify against you in court?

Well, it could. Whether we should let it is another story.

You may have heard of “microexpressions” — Malcolm Gladwell made much of them in Blink, and Fox has a new show, “Lie To Me,” based on the work of Paul Ekman, who discovered the minute facial movements that can reveal emotional states we’re trying to hide (such as deception or fear).

Supposedly, you can learn to read microexpressions in about an hour online (by paying some money to Eckman’s company, of course). But humans are still too slow. Scientists wanted to teach a computer to do the work. And now, apparently, they have.

The article, in Technology Review, contemplates the social implications of having a tool like this:

A technology that accurately detects people’s true emotions possesses tremendous political, social, and commercial potential. What if political commentators had applied it to footage of last year’s U.S. presidential debates, for instance, to reveal if McCain or Obama was lying? Or if lawyers used it to analyze video depositions presented during court trials to determine whether a witness had lied, a finding that could be cited as evidence? Indeed, since the technology mines ordinary video, it might be commodified as a cheap Web service so everybody could use it: people might record job interviews, business negotiations, prenuptial-agreement signings, wedding ceremonies, or any other kind of civil transaction, with an eye toward reviewing them to ascertain the good faith of those involved.

Those applications seem a bit far fetched for now (though, I could see a TV network paying for a microexpression read of a presidential candidate or a celebrity). The real use of something like this would be for national security — evaluating a potential security risk at an airport, analyzing a video of an interrogation.

Still, there’s what Ekman calls “Othello’s Error”:

“Othello read Desdemona’s fear accurately. But he didn’t recognize that the fear of being disbelieved is just like the fear of being caught. Yes, our faces reveal what emotions we’re experiencing, if you can read the signs. What our faces don’t necessarily reveal is what triggered that emotion.” If you don’t know that, interpretation can go far astray. “Rule out all the possible explanations before you conclude that what you’re seeing is a sign of lying about a criminal act,” Ekman warns. “Because very often, it’s not.”

I tend to be optimistic that we’ll get some real mileage out of new deception-detection technologies — though, they’re clearly still in their infancy. But there’s always going to be room for human error and interpretation. For better or worse.