Lie detectors come in many ways to detect that someone is lying. Telling someone is lying can be judged on sweat or nervousness. Lie Detection can also be based on the study of the brain and getting wavelengths that spike this is a polygraph. Does looking at the brain instead looking at physical appearance more accurate? The answer to that question would be no it’s not as accurate as looking at a polygraph and examining the brain. A lie detector lets you know the physiological changes considered to be associated with lying. These studies of lie detection only started studies on this last year. The fMRI is not accurate because of course some people will be nervous being there and running tests. The machine will just make them even more nervous causing the machine to spike and incriminate themselves. The court system isn’t allowing the lie detection methods as evidence just yet due to the chance that it’s not accurate and stable.
The background info that the audience needs is that lie detectors aren’t accurate machines and that's why they aren’t brought into court just yet. The viewpoint of the person getting tested is that they are already nervous that they can have a chance to go to jail. The other point is that they are “accurate” but in most cases they aren’t. On the other hand people think that the people are nervous because they are wrong. Imagine being in their position.. First, being on trail would make a person nervous even if you didn’t do it. Then on top of that then being tested on would of course would make you nervous. I believe that these testing have to be further improved before they are used in the courthouse.