I’ve been watching a show on NetFlix called “Lie to Me.” It is clever, the acting is superb and the show, like all great dramas, presents many moral ambiguities. However, the central premise — that you can determine that people are lying through micro facial expressions, linguistic gestures and body language — is at best on shaky scientific ground.

Lying — especially by people you don’t know very well — is quite difficult to detect. Which is why so many conmen prosper. ‘Traditional’ lie detectors don’t do much better than any other system; they primarily measure stress and produce many false positives. Still, our entire legal and financial system depends on being able to determine whether someone is lying, or more importantly who should we trust.

Years ago, when I was a summer student in Toronto, I was recruited into a graduate study that tried to test exactly how well strangers could read each other. We were asked to answer a set of standard questions — some with the truth, some with lies. The other person was to guess which were which. I asked the supervisor how the results were going so far. Not statistically significant. It didn’t make for as interesting a graduate thesis but that’s science for you. Sometimes the null result is the result you get.

Courts have developed a complex system to measure truth and lies. First of all, we make it a serious offence to lie under oath. You might think that would not deter a determined liar who doesn’t expect to get caught but apparently it does weed out some. People prepared to lie in other situations — for example, to police — are reluctant to do so under oath. For some, the oath actually does involve them with their God. For others it may be more complex.

We also require people to face their accuser — and vice versa. Again, this acts as a deterrent for some and in other cases will actually lead people to lie — that is to deny what happened because they are afraid or embarrassed. Still, history has shown that it is more likely to lead to the truth than not.

Of course, the primary mechanisms to find the truth is cross examination and the comparison of stated testimony to physical evidence. When witnesses are inconsistent or when their story begins to contradict provable facts, we — the judge and jury — may be more inclined to disbelieve them. Still, there can be no doubt that it is at best a flawed system.

Some people are so good at lying — con artists and sociopaths — that even they don’t know when they are telling the truth. Some will actually choose to lie because — in contrast to commonly held aphorisms — it is actually easier to keep track of their lies than to admit to the truth.

It would be nice if we had a perfect way of reading people but we don’t. We’ll just have to muddle through as best we can. Fortunately, in civil societies based on the rule of law and well-ordered systems of trust — we’re pretty good at that.

And that’s ten minutes.


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