Educing Information: Interrogation - National Intelligence University

consuming to emplace properly, and the experience of wearing the electrode array
while being questioned may be onerous for some (although children undergoing
EEG examinations in clinical situations seem to tolerate the experience reasonably
well). Rosenfeld et al. (2004) have found these techniques to be vulnerable to
certain kinds of countermeasures by the subject. Simple countermeasures such as
facial movement may create artifacts. In addition, because the P300 component
of the ERP represents cognitive activity occurring within 300–500 milliseconds
after stimulus onset, stimulus presentations must be repeated for the data to be
based on summation waveforms (Donchin and Farwell, 1991).
Magnetoencephalography (MEG)
Neuronal activation results in a flow of electrical currents, which produces
a weak magnetic field. The magnetic field can be measured by a magnetometer
placed outside the skull. This method of recording brain activity is called
magnetoencephalography (MEG). The area in the brain that has been activated by
a stimulus can be localized by detecting the magnetic fields measured by a series
of MEG recordings.
A thorough review of the literature revealed no studies dealing with MEG and
deception, though there is active research on a closely related topic: MEG and
memory. Temporal resolution is one reason MEG is used in studies of memory
as opposed to other neuroimaging technologies. That is, MEG allows a detailed
analysis of the timing of changes in activation associated with recognition.
Gonsalves et al. (2005) conducted a prototypical study using MEG and the
“remember” versus “know” recognition memory paradigm. This paradigm can be
generally described as follows. Subjects are presented with previously viewed
stimuli and novel stimuli. The subjects are instructed to respond based on the
type of memory they have for the stimulus: that is, if they can recollect the exact
episode in which they saw the stimulus, they would give a “remember” response;
if they have a “feeling of knowing” the stimulus, they would give a “know”
response. Finally, if the subjects believe they have never seen the stimulus before,
they would give a “new” response.
The results of the Gonsalves study suggest that the medial temporal cortex
rapidly signals memory strength by way of reduced activations. The authors
conclude that this may provide a basis for the subjective perception of whether
a stimulus is familiar (“remember” or “know”) or novel (“new”). The ability
to establish “ground truth” relevant to an individual’s memory would clearly
assist the process of detecting deception. It should be noted that this method is
comparable to the GKT/CIT when it is used in conjunction with skin conductance,
heart period variability, and respiratory sinus arrhythmia.
Potential
MEG is a noninvasive technique. However, it is typically performed with a
large, expensive piece of instrumentation that must be contained in an expensive,
magnetically shielded room to reduce external magnetic disturbances. MEG is
therefore not portable. MEG recordings are subject to artifacts from eye blinks,
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