Educing Information: Interrogation - National Intelligence University

The use of the polygraph for security screening or prescreening has been
particularly controversial. There is little research into the screening application
compared to polygraphy focused on single-issue criminal cases (Iacono, 2000;
Krapohl, 2002). In 1983, the U.S. Congress’s Office of Technology Assessment
concluded that “the available research evidence does not establish the scientific
validity of the polygraph test for personnel security screening” (Office of
Technology Assessment, 1983). Recently, the National Academy of Sciences
published a critical review of the state of the art in polygraphy, in which it
concluded that:
Polygraph testing yields an unacceptable choice for [Department
of Energy] DOE employee security screening between too many
loyal employees falsely judged deceptive and too many major
security threats left undetected. Its accuracy in distinguishing
actual or potential security violators from innocent test takers
is insufficient to justify reliance on its use in employee security
screening in federal agencies (Committee to Review the
Scientific Evidence on the Polygraph, 2002, 6-8).
These findings, particularly those related to error rates (especially the rate
of false positives for innocent subjects) and the lack of basic theoretical support,
lead to the conclusion that polygraphy, as currently implemented in the United
States, is insufficient for meeting the needs of national security via employee/
individual screening. The process and application of polygraph testing can be
further improved, although it cannot currently be determined whether these
improvements will meet national security requirements. However, the use of the
GKT/CIT in conjunction with other psychophysiological measures (such as skin
conductance response, respiration line length, eye blink rate, and finger-pulse
volume) has shown promise in distinguishing between informed and uninformed
subjects (Ben-Shakhar and Dolev, 1996; Ben-Shakhar et al., 1999; Elaad and
Ben-Shakhar, 1997; Timm, 1982; Cutrow et al., 1972). Use of the GKT/CIT for
employee/individual screening would require pre-examination work to acquire
known factual data for the development of relevant item sets to test the subject’s
veracity.
Electrogastrogram
The electrogastrogram (EGG) is a device used to diagnose the improper
functioning of stomach muscles or of the nerves controlling those muscles.
Electrodes placed on the stomach surface measure the electrical waves, or pulses,
as they progress downward from the top of the stomach. The stomach typically
pulses three times per minute.
Two researchers (Hutson, 2005) conducted an experiment to test their
hypothesis that the gastrointestinal tract is uniquely sensitive to mental stress
because of the communication between the central nervous system and the enteric
nervous system. Sixteen subjects were given a set of playing cards and told not
to reveal them. Simultaneous EGG and electrocardiogram (EKG) recordings
were taken as the subjects viewed pictures of playing cards on a computer, and
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