1. The eyes are the mirror of the soul?
As reported by psychologists, is a myth. The experts reviewed videotapes of experiments in which some participants reported the truth, while others lied, and they both sometimes quickly glanced from left to right and back, which created the appearance of those "shifty eyes". Liars didn't do it more often than true, so that the eyes can't say cheating or not.
2. The lie detector is lying
In some courts the testimony of polygraphs are accepted as evidence, but to rely entirely on the loyalty of such information impossible. In fact, all lie detectors are based on identifying a person's anxiety and stress, but many deceivers they may not be — it is will say that such data cannot be considered objective.
3. People often lie to themselves
Research conducted in 2011 year showed, for example, that if people are cheating to get the answers to the test task, and this method artificially increase the results, they tend to overestimate their skills, even if you remember that the answers received by dishonest means.