Educing Information: Interrogation - National Intelligence University

of feet when there is a direct line of sight. EMMA is an eye tracking system that
follows the pattern of a subject’s visual attention to a scene, specifically how the
subject’s eye scans a familiar object versus an unfamiliar object. The DoDPI has
published no review studies to date. These methods may hold promise, but are not
currently ready for deployment.
Polygraph
Subtle bodily changes such as heart rate, blood pressure, and skin resistance
are amplified and recorded onto a multichannel writing instrument known as the
polygraph. The polygraph is typically used in conjunction with one or more of a set
of related tests: the Guilty Knowledge Test (GKT), also known as the Concealed
Information Test (CIT) (Ben-Shakhar and Elaad, 2002); the Comparison Question
Test or Control Question Test (CQT) (Raskin and Honts, 2002); or the Relevant/
Irrelevant Test (RIT) (Iacono, 2000). It should be noted that although the CQT
is the most widely used test in North America, its scientific validity has been
criticized (Gronau et al., 2005; Ben-Shakhar et al., 2002). In contrast, the GKT/
CIT, widely used only in Japan, has been supported as an objective test (Gronau
et al., 2005; Ben-Shakhar et al., 2002).
The typical method of scoring the physiological records is for the polygrapher
to look globally at the charts for a “lie response”: an assumed specific response
pattern uniquely associated with lying. Another, more objective, method of scoring
the charts is to measure the relative magnitude of the responses (Backster, 1962);
that is, when the difference between the relevant and control question response
levels reaches a certain quantitative point, the decision is made to classify the
examinee as deceptive.
The polygraph is the most widely employed technical means for detecting
deception. It is also perhaps the most controversial. Almost since its introduction,
polygraphy and its direct technological ancestors have been the subjects of legal
proceedings and Supreme Court decisions, including the Frye case (Frye v. United
States, 54 App. D.C. 46, 293 F. 1013 [1923, D.C. Cir.], in which the testimony of
polygraph pioneer William Marsten was excluded) and the more recent Scheffer
case (United States v. Scheffer, 523 U.S. 303 [1998]). Ironically, the federal
government relies extensively on the polygraph for forensic investigations and
personnel security, yet the results of polygraph tests are generally inadmissible in
federal courts (Greeley, 2004).
Potential
The accuracy of the polygraph is a matter of controversy. Some researchers
believe that the current system with the CQT is no better than chance (c.f. Ben-
Shakhar, 1991; Furedy, 1996; Saxe, 1991). Other researchers estimate the accuracy
at 75% to 80% (i.e., one error, on average, in four to five trials): Elaad and others
(1992) with the GKT/CIT, MacLaren (2001) with the GKT/CIT, and Patrick and
Iacono (1991) with the CQT. Supreme Court Justice John P. Stevens found “a host
of studies that place the reliability of polygraph tests at 85 to 90 percent” (United
States v. Scheffer, 523 U.S. 303, 333, quoted in Greeley, 2004, p. 129).
65