Over the course of human history, the methods used to determine if someone is telling the truth have ranged from horrific to downright silly. The legend of La Bocca della Verita holds that if someone fibs with their hand in the mouth, it gets bitten off.
More recent research looks at brain activity during deception. We also interviewed Britton Chance about the possibility of remote lie detection using infrared examination of brain activity. New research directs our attention to the skin, where sweat gland activity may be detected from a distance. The helical structure of a sweat gland allows it to behave like an antenna for electromagnetic frequencies in the range of 100 GHz.
Skeptics note that this is just another way to detect stress, not lies. Even the researchers say the most appropriate application of the technology is to monitor medical patients or athletes.