nopolycop wrote on Jan 15^th, 2008 at 7:46pm:

[ Correct me if I am wrong, but a poly exam is supposed to be able to tell if a person is lying or telling the truth correct?

Well, strictly speaking, you are wrong. Unless you insist on having this conversation in vague and inaccurate colloquialisms. It is common when discussing complex or unfamiliar phenomena to borrow concepts and language from more familiar contexts, but it is both reductionistic and inaccurate to stop there.

Polygraph, is casually referred to as a lie detector, but that term does not adequately define or describe the test. The term psychophysiological detection of deception, though chunky, is better better because it describes what is intended - the detection of deception through the measurement of physiological response to a stimulus. The stimulus is in the form of a question about involvement in a behavior or event.

In the language of testing, polygraph is simply intended to measure whether physiological reaction to the stimulus fits a model at some expected level of statistical significance.

sergeant1107:
Quote:

When one takes a polygraph test, what is supposedly being tested is the subject's answers with regards to truth or deception.

Not quite. What is being tested is the subject's reactions to the stimulus, and whether those reaction are a good or poor fit for a model.


r