Even high-tech lie detectors don’t detect lies as such; they merely detect the physical cues of emotions, which may or may not correspond to what the person being tested is saying. Polygraphs, for instance, measure respiration, heart rate and skin conductivity, which tend to increase when people are nervous – as they usually are when lying. Nervous people typically perspire, and the salts contained in perspiration conducts electricity. That’s why sudden leap in skin conductivity indicates nervousness -about getting caught, perhaps -which makes, in turn, suggest that someone is being economical with the truth. On the other hand, it might also mean that the lights in the television Studio are too hot- which is one reason polygraph tests are inadmissible in court. “Good lie detectors don’t rely on a single thing” says Ekma ,but interpret clusters of verbal and non-verbal clues that suggest someone might be lying.”