[user104658]

Originally Posted by Cherie

Pretty sure they canned the lie detector tests a few series ago, probably tweets from the public

Lie detectors are bull****, far too open to interpretation and interference from things like anxiety, and also people who lie as second nature often beat them anyway. If the "magic psychic machines" actually worked we wouldn't need court systems and juries... we'd just hook people up and find out the 100% truth straight away .

The only real use in them isn't to say "you were lying!!", it's just to be able to say "...that question made you nervous?" - which could be for any number of reasons - but in the sense of a criminal investigation a question making someone nervous could be useful. It doesn't "prove" anything but it might identify an topic to look into more deeply.

But yeah for example someone spiking all over the place when they're asked something like "Do you love ____?" and they say "yes" means nothing, because they could be spiking because they're lying, but they could also be spiking if it's true but they're uncomfortable being vulnerable.