How does polygraph test work?
What is a polygraph test? In short, polygraph tests record a number of different bodily responses which can then be used to determine whether someone is telling the truth. They usually measure things like blood pressure, changes in a person’s breathing, and sweating on the palms.
What are the 4 physiological responses used to detect lying in a polygraph test?
Polygraphs measure physiological arousal factors, including heart rate, blood pressure, respiration, perspiration, and skin conductivity. The theory of the lie detector test is that these physiological responses will be different when the subject is truthful versus when the subject lies.
What is the theory of polygraph examination?
The most commonly accepted theory at present is that, when the person being examined fears detection, that fear produces a measurable physiological reaction when the person responds deceptively. Thus, in this theory, the polygraph instrument is measuring the fear of detection rather than deception per se.
How does a polygraph relate to the theories of emotion?
The assumption is that most of us would show signs of physiological arousal if we were being dishonest with someone. A polygraph, or lie detector test, measures the physiological arousal of an individual responding to a series of questions.
How to test your fight or flight response?
Test your knowledge of the fight-or-flight response with this revision quiz. How well do you understand the fight-or-flight response? What causes it and what are the signs of this bodily response?
How does a polygraph work to detect guilt?
The polygraph then detects changes in heart rate, respiration rate, blood pressure, and muscular movement. Increases in these variables after a question is asked may be interpreted as a guilt response to a lie, and the answer to this particular question may be interpreted as a lie, and not the truth.
Why do some people lie on a polygraph?
So if you have anxiety and nervousness during a polygraph, your answer to a question and your subsequent adrenaline response might be misinterpreted as guilt, and hence a lie on the polygraph. Being emotional can affect the results of your polygraph, as anger and surprise can also set off the adrenaline response, in addition to anxiety and guilt.
Why do you sweat more during a polygraph test?
Finally, you sweat more during lying, a cooling mechanism responding to our increased body temperature due to increased overall blood flow. The most advanced polygraphs are used to detect all these changes in the human body; simple machines tend to focus on heart or breathing rate only.