John Larson, working under August Vollmer at Berkeley, California, developed the first portable polygraph (lie detector) instrument in 1921, capable of recording blood pressure, respiration, and pulse simultaneously during interrogation. Larson used the device in actual criminal investigations in Berkeley, beginning the long and contested history of polygraph evidence in criminal justice. Though polygraph results have never been universally admissible in court, the lie detector became one of the most culturally visible symbols of scientific evidence gathering in the twentieth century.

The lie detector became an extraordinarily potent cultural symbol of the attempt to make the body yield confessional evidence involuntarily — a reversal of the tortured confession with scientific apparatus substituted for physical coercion. The polygraph as metaphor for interiority and compelled truth permeates mid-twentieth-century American literature and poetry. Writers including Don DeLillo engaged with the polygraph as a symbol of the surveillance state's demand that the citizen's body become transparent evidence.