Brain-Scan Lie Detectors Don’t Work

I’ve told this story many times, but, hey, why not once more? I had a string of letters after my super-duper top secret clearance when I was in the Air Force, standard for crypto guys. To reduce the chance of spies in our midst the AF hopefully employed an outside contractor which ran lie-detector spy screenings.

This was back in the medieval torture days. Constricting straps around the chest and arms, wires leading everywhere, beeping machines, hot lights, absolute stillness required. First the “calibration”. The guy who stands behind you asks you to think of the number seven, after which he says he’ll ask you if you’re thinking of the numbers one through ten and that you’re to say “No” to each, even seven.

So you do. After which he shows you a squiggle that looks exactly like every other squiggle and says, “See? That’s where you ‘lied’ and said you didn’t think of seven.” If you’re smart, you agree. Why cause trouble?

The questions come and eventually stop. After which, invariably, the guys says, “Sergeant Briggs. Looks like we have a little trouble with one of the questions. Think you can help me out with that?” Any but a fool says, “Huh? I don’t know.” Play dumb. Maybe the guy fishes around a bit, but if you sit happy and stupid, he lets you go.

Now I have seen pathological liars go through this process and pass (Shawn, remember JK?). Every one of the big-name spies you’ve heard about, and all the small ones you haven’t, also passed. Conclusion: lie detectors don’t work.

But that was the old stuff. Now they’re doing brain scans, which is as sciencey and science gets, right? The whitecoats figure all they have to do is to peer at the right spot in the brain, the spot where lies originate, ask you a question, and then wait to see if the spot “lights up.” If so, you’re lying, n’est-ce pas?

Or maybe not the lie area of the brain, but how about the guilt lobe? Liars always feel guilty telling lies, don’t they? Seems fMRIs ought to be able to sniff out guilty versus non-guilty brains. Maybe the color on the screens of the brain-scanning machines goes green, or it could be chartreuse.

Lying is simple. It’s the telling of something believed to be false. It is the will willfully acting at variance to the truth. Or, no. How can it be willed action? Since lying has to begin in the brain, as the philosophy of materialism asserts, and there is no will only the illusion of the same, leaving aside the question of “who” is doing the “illusioning,” we should, at least in principle, be able to section the little grey cells until we can spot a fabrication under the microscope.

Anyway, the Pacific Standard (tag-line “The Science of Society”) reports on yet another new study which says brain-scan lie detectors don’t work because “perpetrators” can “suppress crime memories.” The press release is more sedate “people can intentionally and voluntarily suppress unwanted memories.”

Which we did not need science to tell us. That people can forget has been known long before anybody invented a computer. Why, not only can people suppress unwanted memories, they can forget all sorts of things. Just ask the Blonde Bombshell if Yours Truly can remember to take the dishes out the washer. But if you were to ask me, I’d say, sure I did it. At least, I think I did. I seem to recall it.

Can’t go much by the study, which is another in a long string of highly artificial situation experiments. This had people simulate crimes and pretend not to remember them, which some could do. At least according to the brain-scan sniffers, which couldn’t find the suppressed memories of pretend crimes.

In real crimes if there wasn’t indisputable corroborative proof, there would be a person’s word against some colored pictures, which folks like me could show are easy to misinterpret. Some people would believe the pictures but have doubts, others wouldn’t believe. We’re in the same spot we’ve been in forever. Some people crack under questioning, some don’t. Some lie, some don’t.