Theory of Polygraph Science (Forensic Psychophysiology):
The underlying theory of how the polygraph instrument identifies the particular arousal pattern for each channel does not rely on fight, freeze or flight i.e. threat of punishment, consequences of being caught lying or even psychological set. Nor is it a conditioned response, or related to anxiety (there is no basis in research for this). These notions are outdated and irrelevant to modern polygraph science. Current understanding refers to what is known as the ‘orienting response’ to novel or important stimuli, which are intrinsically related to experiences in autobiographical memory, emotional salience and the act of lying requiring increased cognitive processing. Specifically, it takes more cognitive activity to lie than to tell the truth because you need to construct a narrative, so the degree of cognitive processing can be relevant in determining deception. This collection of underlying neural processes give rise to increased autonomic arousal that is routinely detected by the polygraph instrument. Thus, essentially, we are analysing the strength of attention as determined by autonomic arousal.