In 1955, researchers Paul Meehl and Albert Rosen published a landmark paper in the Psychological Bulletin demonstrating that when two independent diagnostic tests are applied sequentially to the same issue — what they termed a "successive hurdles" model — the combined outcome confidence increases substantially beyond what either test could achieve alone. Their work showed that these gains are incremental, depend on the base rates of the population being tested, and are constrained by the validity of each individual test.
For decades, polygraph examiners recognized the theoretical power of this model but could not apply it in practice. The reason is straightforward: two successive polygraph examinations are not independent of one another. The same physiological pathways are engaged, the same countermeasure vulnerabilities exist, and correlated measurements cannot satisfy the mathematical independence requirement that makes successive hurdles work.
The emergence of EyeDetect — a computer-administered, eye-movement-based credibility assessment tool developed by Converus — changed that equation entirely. EyeDetect measures a fundamentally different set of biometric signals (ocular-motor responses, cognitive load, pupil dilation patterns) through a completely different administration method, with no examiner present and no traditional polygraph sensors involved. For the first time, a polygraph examination and EyeDetect can be combined as two largely independent tests on the same issue, making the successive hurdles model practically applicable in real-world credibility assessment.
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