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Comment by KingMob | Hacker News Reader

Former cognitive neuroscientist here. In all seriousness, if this technology were dropped in today, it would be hard to use surreptitiously; you still need to immobilize the head to get a good fMRI signal at current speeds.

Also, interpreting a brain scan to determine lying is way beyond our actual abilities (though sadly, there are Indian courts and companies doing just that, despite the warnings of the neuroscience community).

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Also, IIRC from "lying experts", there is no such thing as an objective lie. If you have no anxiety about the lie (I think I was reading about Lance Armstrong on this), or you don't think you're lying, you can easily pass a polygraph test.

You can habituate your brain to follow certain patterns even if you do know you're lying. I suspect there will never be a "magic lie detector" with any reliability for people who understand what is happening or take preventative measures.

I heard similar and figured it was a signal to noise problem. In that it was impossible to reliably eliminate false positives (the anxiety of someone normal being polygraphed) while still detecting trained liars (who minimize their anxiety while still lying).

Still better than being inside those incredibly loud machines. I expected a "spinning" noise of some kind, not the jackhammer concerto.

Also, I had no idea courts in India were using that as a detection method; that's insane. I hope to god they don't use it as absolute evidence...

You know that our security services and, more disturbingly, our prosecutors' offices still use the polygraph, right?

ya but when polygraphed .. you are aware that you are getting polygraphed. but secretly scanned from an adjacent room... that my friend is in the realm of science fiction...lol

My point was more that before condemning the Indians, we should remove the log from our own eye.

It's getting there. Polygraphs are still useful to measure ~~psychological~~ neurological response, so we might not see them disappear. I could certainly still find it convincing if corroborated with a psych expert who understands how to read it (and when NOT to draw a conclusion). The idea of discerning a lie with any reliability with a machine and no access to any direct evidence is absurd, though.

Yeah, the polygraph is no better. Homeland Security approached my old prof about building a field lie detector using just a computer and RTs. As part of their visit, they talked about their lie detection abilities, their motion-sensitive chairs, specially-built rooms, and super-investigators. I just rolled my eyes.

sounds like a modern version of the floating = witch test

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