The development of a successful lie detector has been a dream of governments and law enforcement since ancient times. A Hindu Veda written around 900 B.C.E. suggests a strategy for detecting lying behavior in suspects:
A person who gives poison may be recognized. He does not answer questions, or they are evasive answers; he speaks nonsense, rubs the great toe along the ground, and shivers; his face is discolored; he rubs the roots of the hair with his fingers; and he tries by every means to leave the house … .
Six hundred years later, the Greeks were attempting to detect lies by feeling the suspect's pulse. What is interesting about both the early Hindu and Greek examples is that the methods employed were empirical; the interrogators were looking for physiological changes in the body that corresponded to the mental state in question.