Nobody has ever found a lie detector that works

Nobody has ever found a lie detector that works

Despite the fact that lie detector test results are admissible in some courts as evidence, there is ample evidence that it is relatively easy to fool common lie detectors. Essentially, all lie detectors measure are levels of stress and anxiety — and, given that many liars are cool and practiced under pressure, this doesn't tell you much about how truthful they're being. Some have suggested that we use fMRI brain imaging for lie detection, but there is even less evidence that lies can be detected in that way. Interestingly, there is evidence that using transcranial magnetic stimulation can induce people to lie more often than they normally would. And there are a few other lie detectors that could one day be foolproof.