Assisted Detection

Polygraphs
Current polygraph testing begs false positives and alternative detection technology is expensive, invasive and cumbersome. The FBI’s Webster Commission recognizes the polygraph as flawed due to its false positive potential. Polygraphs measure primarily for physiological responses and are an indirect indicator of anxiety that may relate to heightened conditions brought on by lying, providing the subject isn’t savvy to countermeasures that render polygraphs useless. 

Polygraph reliability is questionable since multiple testing contexts with low variability rarely produce the same outcomes. Accuracy wanes depending on the situation; polygraphs tend to be more accurate in criminal investigations than in screening future employees. 


Since the polygraph measures physiological tells and these tells relate to the subjects' psychological arousal, the validity of polygraph testing is threatened simply due to the varied nature of subject responses under certain stimulus conditions. Heart rate, blood pressure, respiratory rates and sweating have no correlative baseline, and when subjects are already heightened due to anxiety of not being found truthful when in actuality they are, polygraphs record data that lead operators to false positives. 

As well, polygraphs are ineffective in detecting major security threats and are useless in determining deception in subjects engaged in countermeasures against detection.   

Polygraphs are invasive causing latent anxiety secondary to proofs searched for in the process. They depend on psychophysiological indicators including respiration, heart rate, blood pressure, eccrine secretions that change electrical conductivity; autonomic and somatic activity that until now are not detectable without invasive telemetry. These anxiety indicators can mask primary tells of lying.


Positron Emission Tomography

Other detection technologies include positron emission tomography (PET) where brain activity can be measured, and functional magnetic resonating imaging (fMRI), in recording event-related characteristics of brain activity following discrete stimuli.  

These technologies depend on cumbersome equipment tied to a central location costing millions to acquire and maintain along with additional personnel to operate, and yet the data they provide are shallow. 


Thermography

Thermography has been used in experimentation with the Department of Defense Polygraph Institute (DoDPI) to detect changes in radiant energy from study participants' faces. This non-invasive technique is effective in detecting temperature changes in the face, a flush consistent with emotional escalation, though like PET and fMRI, thermography is expensive, requires a technician to operate and provides shallow data. 

Eye Tracking

Human Observation
Human observation is used along with these technologies to detect and confirm deception. Nonverbal indicators including occulesics (eye behavior), kinetics (body movement), paralinguistics (verbal emphases, semantic aphasia, and non-semantic tells), kinesics (specific non-verbal gesticulation), haptics (touch, self-touch), and proxemics (territory, spatial relationships, and artifacts). Human observation has proven extraordinarily effective in lie detection due to its vast data of indications, but relies heavily on trained and experienced human detectors. 

At issue in global contexts where the truth is increasingly difficult to discern, current lie-detection technologies lack accuracy, validity and reliability. Inter-agency studies conclude the polygraph marginal in its efficacy of determining whether a subject is lying.