The polygraph, lie detector, how it works the machine of truth?
We must begin by clarifying that we do wrong to call a polygraph polygraph as a polygraph does not have the ability to detect deception or truth. It is a device that measures the fluctuation of certain vital variables compared to certain stimuli, shaping it on a continuous paper. In this case, questions and answers which is particularly interesting result for us. He is a specialist who will read the report providing the polygraph and based on the reaction of the subject, decide whether they are telling the truth or lying. For this, the polygraph, whose name comes from poly (various) and graph (graphics), measured the following variables: • Respiration, measured by two rubber hoses filled with air: one on the chest and abdomen. These tubes, called neumografs, control the flow of air into the chest cavity. • Blood Pressure / beats per minute, measured by a cuff placed on bare arm • The galvanic skin resistance. While this may sound strange, refers simply to the perspiration of the skin.
