Question

Describe the polygraph and discuss its controversy regarding its use as a “lie detector”, utilizing both the James-Lange theory and the two-factor theory in your response.

Answer 1

Polygraph is a method used in the interrogation of the suspect by the police department or concerned authority to identify whether the statements to which a suspect agrees on is an absolute lie or an honest opinion. This method purely works based on the principle that any sort of "lie" told by an individual will produce certain physiological changes in his body such as a change in blood pressure, pulse rate deviation, etc. It is this physiological change happening in the body that happens first following which a lie is being said. However, the controversy here is that many people who are honest and genuine may have a change in pulse or blood pressure when accepting truth which could be wrongly detected by polygraph as a suspect telling "lie". Similarly, suspects who are telling a lie may also be non-anxious and there would be practically no change in physiological parameters observed which gets wrongly interpreted by the machine as the suspect is telling truth.

Both James Lange theory and the two-factor theory works on a similar principle as that of the working principle behind a polygraph. The principle is that it is always the physiological change that happens first in our body following which an emotion gets elicited.