Educing Information: Interrogation - National Intelligence University

The differences in experimental design may also explain the activation of the
anterior cingulate cortex only during the pretending not to know condition, versus
the consistent anterior cingulate activation reported by Langleben et al. (2002),
Ganis et al. (2003), and Kozel et al. (2004a,b).
Potential
PET scanning is invasive and non-portable. Scientific PET investigations
require clearance by an ethics committee because of the injection of radioactive
material, and because multiple scans of a subject should be limited. Only a few
hospitals and universities can perform PET scans because of the high costs of
producing the radioisotopes used in the process. Given these limitations, and that
the laboratory results of one PET study conflicted with the results of several fMRI
studies of deception, this technology is not ready to be deployed.
Functional Magnetic Resonance Imaging (fMRI)
fMRI is a relatively recent technique (circa early 1990s) that uses a powerful
static magnetic field, usually 1.5 to 5 tesla (T) or more, to align the nuclear spins
of protons in the sample under study (e.g., the subject’s brain). If the equilibrium
spin alignment is perturbed with a transmitted radiofrequency pulse, the sample
will emit a corresponding transmission as it returns to equilibrium. Because the
magnetic properties of oxygenated hemoglobin differ from those of deoxygenated
hemoglobin, the emitted signal is differentiable. Consequently, the fMRI system
can form a sequence of images of the brain indicating those areas in which the
oxidative brain metabolism — and, by inference, the neural activity — is higher
during the performance of one task than in another (e.g., lying compared to telling
the truth). fMRI relies on large superconducting magnets, cooled with cryogens
to within a few degrees of absolute zero, to produce the intense static magnetic
field required.
The last five years have seen the publication of several research papers
describing the use of fMRI as a means of detecting deception.
• Spence et al. (2001) investigated subjects who saw or heard statements
about their own activities that day and signaled whether they concurred
with the statement by pressing the appropriate button (yes or no).
However, if the display used a particular color, the subject was to “lie”
by pressing the incorrect button.
• Langleben et al. (2002) used images of playing cards to implement a
modified version of the polygraph GKT/CIT paradigm. Participants were
given a playing card and instructed to attempt to fool a computer that was
evaluating their responses by denying that they had that particular card
when queried, but to respond truthfully otherwise. The subjects were
promised a modest reward ($20) if they succeeded.
• Lee et al. (2002) investigated a malingering paradigm in which subjects
pretended to have a memory impairment by making intentional errors, at
their own discretion, during a forced-choice memory task using numbers
and autobiographical information.
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