Red face, sweaty hands? Contrary to the claims of many self-proclaimed experts, body language reveals little about our inner workings. Evidence of dishonesty can be found elsewhere.
There’s a lot of money to be made in psychology if you do it badly enough. Anyone who disregards the current state of research can advertise with big promises. Then you can claim, for example, that it is enough to read the book of a lying expert with a CIA past, and you can already recognize any deception by blinking frequency and forehead moisture. Or: Attending a body language guru’s weekend seminar is enough to learn the three moves with which you can grab every conversation partner. Or they advertise a program worth billions so that specially trained security personnel at US airports can identify potential terrorists before they even check in using 92 behavioral indicators, such as excessive clearing of the throat or whistling a song.