Educing Information: Interrogation - National Intelligence University

that neither system was fully automated; each involved some degree of manual
preprocessing. The CMU/Pitt team (Cohen et al., 2001) required less manual
preprocessing than the UCSD/Salk team (Bartlett et al., 2001). Both systems
were tested with spontaneous facial behavior video recorded from a prior study
of deception (Frank and Ekman, 1997). However, no analysis was made of
AUs based on deception/truth-telling conditions. Only two AU categories were
recognized: eye blinks (see the section on “Eye Blinks, Saccades and Fixations”
below) and brow region movement. The CMU/Pitt team recognized AUs in the
brow region with 57% accuracy, and the UCSD/Salk team recognized brow raises
with 91% accuracy and discriminated between brow raises and brow lowering
with 94% accuracy. All of these accuracies were based on agreement with human
coders.
Since these first efforts in 2001, two real-time, fully automated systems have
been developed to recognize facial expressions (Tian et al., 2003; Littlewort et
al., 2004). Both systems classify facial expressions according to the following
emotion categories: happiness, sadness, surprise, disgust, fear, anger, and neutral.
One significant difference in the testing of these two systems is that Littlewort
et al. (2004) tested their system on a group of subjects instructed to generate
a specific series of facial expressions, whereas Tian et al. (2003) tested their
system on subjects looking at other subjects who displayed spontaneous facial
expressions. This difference is relevant for real-world applications because it has
been shown that spontaneous facial expressions differ from posed expressions in
several ways (Ekman, 1991).
Potential
Spontaneous facial expression measures can be recorded non-intrusively,
and without the subject’s awareness, provided there is direct line of sight. The
measures can be made in real time via portable technology (a video camera and
computer system capable of high-speed image processing). However, to date
there has been no research into an automated means of measuring deception on
the basis of facial expressions. Measurements of facial expressions and deception
have been limited to manual coding by trained humans, which is labor intensive,
human-observer dependent, and difficult to standardize. Significant research
efforts are required to determine whether FACS measurements are sufficient for
an automated system to distinguish between truth and deception; that is, whether
measures of additional factors, such as body posture and tone of voice, might be
necessary.
Eye Blinks, Saccades, and Fixations
An eye blink occurs when one or both eyes are closed and opened rapidly.
Ocular movements are typically divided into fixations and saccades. A saccade is
a rapid, intermittent eye movement that occurs when the eyes look quickly from
one thing to another. The human eye saccades because only the central part of the
retina has a high concentration of color-sensitive nerve endings that are capable
of formulating a high-resolution mental map of the scene being viewed. The eye
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