Methods for the detection of deception are based on the fact that various autonomic and voluntary bodily changes accompany deception, particularly when the subject is aware of the examination procedures and purpose of the test. Blood pressure, heart rate, respiration, psychogalvanic reflexes, and voluntary muscular reflexes can all be conveniently recorded. The polygraph device described here consists of three units, one recording continuously and quantitatively the subject's blood pressure and pulse, one giving a duplicate blood-pressure pulse curve taken from some other part of the subject's body, and the third recording respiration. Types of simple experimental tests include the card, map, number, name, and age tests. Results are interpreted through readings of the various bodily changes in relationship to questions asked. Examination procedures in criminal and personnel cases include the peak of tension test, specific response test, word association test, sensory tests, and psychopathic tests. The greatest accuracy in polygraph examinations is obtained when the suspect has not been given all the details of the crime or results of the police investigation. 3 references