Booking a Polygraph Test?
Our Test Reads Recognition, Not Your Nerves

Why We Use EEG Rather Than a Polygraph

A polygraph does not measure lies directly. It records physiological arousal - heart rate, blood pressure, breathing and sweating - while you answer questions, and a trained examiner scores how those signals change between question types. The difficulty is that arousal has many innocent causes. Fear, embarrassment, medication and the simple dread of being wired to a machine can all produce it.

That is why the polygraph's best-documented risk is the false positive: an honest but anxious person scoring as deceptive. On accuracy, the practitioner body's own meta-analysis (American Polygraph Association, 2011) reports roughly 87-89% for validated single-issue techniques, while the most thorough independent review, the US National Academy of Sciences in 2003, found laboratory accuracy well above chance but well below perfection and the field evidence weaker. Both agree that question design and examiner skill matter a great deal.

P300 EEG: Testing Recognition, Not Stress

Instead of watching your body sweat, our test listens to your brain. EEG sensors record your brain's electrical activity while details connected to the events under investigation are presented alongside neutral items. When the brain recognises something it has genuinely encountered before, it produces a characteristic electrical response roughly 300 milliseconds after the stimulus appears. That response is the P300.

The P300 is involuntary. It appears within about a third of a second, before you have had time to think about it. And because the test is looking for recognition rather than stress, you do not need to try to stay calm, slow your breathing or control your heart rate. There is nothing for you to manage.

Controlled laboratory studies of the P300 concealed information test typically report 80-95% correct classification, with limited field validation so far; those are published figures about the method, not results from our own testing. Countermeasures are not impossible: Rosenfeld and colleagues showed in 2004 that the original protocol could be defeated, which is why later protocols were designed to detect or resist them. What the method does change is the nerves problem: because nervousness does not by itself create a recognition response, an anxious but truthful person is not penalised for being anxious.

Side by side

Figures above are attributed to published research and describe the methods in general, not results from our own testing. For the sources, see our Polygraph vs P300 comparison and P300 explained pages.

What the Test Actually Feels Like

Most people arrive expecting a polygraph: chest straps, a blood pressure cuff and an examiner watching every flicker. Here is what happens instead.

• No straps, cuffs or finger clips. Just a lightweight 4-channel EEG headband.
• You sit comfortably and watch a screen. Words or images appear in sequence while the headband records.
• Every question is agreed with you first. Nothing comes up on the day that you have not seen.
• You do not have to stay calm. Your heart rate, breathing and sweat are not recorded at all.
• The one thing we ask: keep reasonably still while items are on screen, because movement can blur the EEG signal.
• If the signal is not clear enough to call, the report says so plainly rather than forcing a result.
• Around 60 to 90 minutes in total, including the consultation and a debrief.

Sources

Our method is based on the published P300 concealed information protocols developed by J. Peter Rosenfeld at Northwestern University. We have no affiliation with him or his laboratory. Figures on this page describe the methods in general, not results from our own testing.

• National Research Council (2003). The Polygraph and Lie Detection. National Academies Press. doi: 10.17226/10420.
• Rosenfeld, J.P. et al. (2008). The Complex Trial Protocol (CTP): a new, countermeasure-resistant, accurate P300-based method for detection of concealed information. Psychophysiology, 45, 906-919.
• Rosenfeld, J.P. et al. (2013). Review of recent studies and issues regarding the P300-based complex trial protocol for detection of concealed information. International Journal of Psychophysiology, 90, 118.
• Rosenfeld, J.P. et al. (2004). Simple, effective countermeasures to P300-based tests of detection of concealed information. Psychophysiology, 41, 205-219.
• American Polygraph Association (2011). Meta-analytic survey of criterion accuracy of validated polygraph techniques. Polygraph, 40(4).