How does a lie detector machine work?

Answer by  fishy (1085)

Lie detectors measure bodily reactions to questions and answers. During questioning, it will measure slight changes in skin temperature, heart rate, breathing changes and so forth to determine if they have changed from the benchmark questions.

Answer by  nuttree (1596)

A lie detector uses sensors to measure blood pressure, pulse, breathing and skin conductivity. The theory is that lying is stressful; when you lie, your pulse, blood pressure, respiration and skin conductivity (from sweat) change. But some people lie without showing these changes, so lie detectors do not always work.

Answer by  skdo (113)

A lie detector, or polygraph, measures several attributes such as blood pressure, pulse, and breathing. When a person is lying, they will often have noticeable changes in these areas.

Answer by  km8738 (1917)

A lie detector machine monitors various functions of your body and their difference between when they are at a resting state and a stressed out state.