-----BEGIN PGP SIGNED MESSAGE-----
Until machines become smarter than we are I don't think they will be able to detect deception better than humans already can. We're already very sophisticated in this because it isn't an abstract game like chess or solving differential equations which we're lousy at, Evolution would grant a huge advantage to those who are good at detecting lies and to those who are good at concealing their lies. Perhaps machines would have senses we don't have (MRI?, CAT SCAN? PET SCAN?) and detect lies that way but it still wouldn't be easy and is probably not practical in everyday situations. Another problem is that the most dangerous and horrible monsters are also sincere monsters. I don't think it was just an act, I think Hitler really thought Jews were subhuman and that he was doing a good thing by butchering them. Sincerity is a vastly overrated virtue.
Certainly in the present day I have no confidence in lie detectors. Even if I was innocent I'd know that the way I react when they ask "Did you kill Mr. Smith?" will determine if I live or die, so I'd be trying so hard to remain calm that my reading would probably go through the roof. I would only consent to a lie detector test if I was guilty of the crime and had nothing to lose because there was very good evidence of my guilt. I've read of a good way to beat the machine, put a tack in your shoe. They always start with innocuous control questions to get a base line, "Is your name John K Clark?" I jab my toe with the tack and say "yes", " are you 6 feet 3 inches tall?" I jab my toe with the tack and say "yes", then they get down to business, "Did you kill Mr. Smith?" I do NOT jab my toe with the tack and say no. Because of this the first thing I do every day when I get up in the morning is put a tack in my shoe, after all, you never know. If you lack my foresight try biting your lip.
John K Clark firstname.lastname@example.org
-----BEGIN PGP SIGNATURE-----
Version: PGP for Personal Privacy 5.5.5
-----END PGP SIGNATURE-----