I said it above, but to carry on with what tokenadult said; Lie detection is a little more complicated than detecting facial expressions. If you have a defensiv

I said it above, but to carry on with what tokenadult said; Lie detection is a little more complicated than detecting facial expressions. If you have a defensive, introverted person looking downward, they might be lying or that could be how he responds to whatever interrogation they are under. Conversely, a mentally distressed individual (or someone who has done a heavy amount of NLP) could lie straight to your face because they personally believe they are telling the truth. This type of technology will no doubt be used to attempt lie detection, but it won't work. The only thing we can do is use the context clues of the face to infer what we think is going on.