Nathan J Gordon, William L Fleisher
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accurately detects deception and requires no attachments very useful. Unfortunately, scien-
tific studies on the validity of voice stress have not been very promising. In 2006, Sujeeta
Bhati and Susan E. Brandon submitted a paper, “Review of Voice Stress Based Technologies
for the Detection of Deception,” to the U.S. Department of Defense. They reviewed
24 empirical studies that had been conducted over a period of more than 30 years, and
concluded that the studies failed to provide evidence for the validity or reliability of
voice stress analysis-based technologies in the detection of deception. These studies utilized
Layered Voice Stress Analysis (LVA), Computerized Voice Stress Analysis (CVSA), Psycho-
logical Stress Evaluation (PSE), Vericator, Diogenes, Mark II Voice Analyzer, and the
Voice Stress Analyzer (VSA).
The following is a partial list of the studies conducted on voice stress in the detection of
deception and their results:
P. Damphouse, M. Upchurch, Assessing the validity of voice stress analysis tools in a jail
setting, Oklahoma Department of Mental Health and Substance Abuse, 2007. Conclusion:
LVA and CVSA have poor validity in detecting deception – base rate accuracy was 68%.
H. Hollien, Voice stress analyzer instrumentation evaluation, University of Florida, 2006.
Conclusion: LVA and CVSA have poor validity in detecting deception. LVA accuracy
was below chance; CVSA accuracy was a little better than chance.
Cassidy, Assessing questioning protocols in detecting deception by voice analysis, 2006.
Conclusion: Accuracy of the CVSA is below chance.
M.J. Janniro, V.L. Cestaro, Effectiveness of detection of deception examinations using the
Computer Voice Stress Analyzer (DoDPI95-P-0016). Department of Defense Polygraph
Institute, Fort McClellan, AL, 1996. DTIC AD Number A318986. Conclusion: Chance-level
detection of deception using the CVSA as a voice stress device.
V.L. Cestaro, A comparison between decision accuracy rates obtained using the poly-
graph instrument and the Computer Voice Stress Analyzer (CVSA) in the absence of
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jeopardy (DoDPI95-R-0002). Department of Defense Polygraph Institute, Fort McClellan,
AL, 1995. Conclusion: Accuracy was not significantly greater than chance for the CVSA.
D. O’Hair, M.J. Cody, S. Wang, E.Y. Chao, Vocal stress and deception detection among
Chinese, Communication Quarterly 38 (2) (Spring) (1990) 158ff. Conclusion: Partial replica-
tion of preceding study. Vocal scores were not related to deception.
H. Hollien, L. Geison, J.W. Hicks Jr., Voice stress analysis and lie detection, J. Forensic
Sci. 32 (2) (1987) 405–418. Conclusions: Chance-level detection of stress. Chance-level
detection of lies.
R.F. Waln, R.G. Downey, Voice stress analysis: use of telephone recordings, J. Bus.
Psychol. 1 (4) (1987) 379–389. Conclusion: Voice stress methodology did not show suffi-
cient reliability to warrant its use as a selection procedure for employment.
D. O’Hair, M.J. Cody, R.R. Behnke, Communication apprehension and vocal stress as
indices of deception, The Western Journal of Speech Communication 49 (1985) 286–300.
Conclusions: Only one subgroup showed a detection rate significantly better than
chance, and it did so by the thinnest of margins. Use of questionable statistical methods
in this study suggests that the modest positive findings would not be replicated in other
research. See next citation.
B.F. Fuller, Reliability and validity of an interval measure of vocal stress, Psychol. Med.
14 (1) (1984) 159–166. Conclusion: Validity of voice stress measures was poor.
H.W. Timm, The efficacy of the psychological stress evaluator in detecting deception,
Journal of Police Science and Administration 11 (1) (1983) 62–68. Conclusion: Chance-level
detection of deception.
M. Brenner, H. Branscomb, G.E. Schwartz, Psychological stress evaluator: two tests of a
vocal measure, Psychophysiology 16 (4) (1979) 351–357. Conclusion: “Validity of the anal-
ysis for practical lie detection is questionable.”
DoDPI Research Division Staff, J.L. Meyerhoff, G.A. Saviolakis, M.L. Koenig, D.L. Yourick
(In press). Physiological and biochemical measures of stress compared to voice stress anal-
ysis using the Computer Voice Stress Analyzer (CVSA) (DoDPI01-R-0001). Department of
Defense Polygraph Institute. Conclusion: Direct test of the CVSA against medical markers
for stress (blood pressure, plasma ACTH, salivary cortisol) found that CVSA examiners
could not detect known stress. This project was a collaborative effort with Walter Reed
Army Institute of Research.
F.S. Horvath, Effect of different motivational instructions on detection of deception
with the psychological stress evaluator and the galvanic skin response, J. Appl. Psychol.
64 (3) (June) (1979) 323–330. Conclusion: Voice stress did not detect deception greater
than chance.
B.E. Lynch, D.R. Henry, A validity study of the psychological stress evaluator, Can. J. Behav.
Sci. 11 (1) (1979) 89–94. Conclusion: Chance level detection of stress using the voice.
F.S. Horvath, An experimental comparison of the psychological stress evaluator and the
galvanic skin response in detection of deception, J. Appl. Psychol. 63 (3) (1978) 338–344.
Conclusion: Chance-level detection of deception.
J.F. Kubis, Comparison of voice analysis and polygraph as lie detection procedures
(Technical Report No. LWL-CR-03B70, Contract DAAD05-72-C-0217), U.S. Army Land
Warfare Laboratory, Aberdeen Proving Ground, MD, 1973. Conclusion: Chance-level
detection of deception for voice analysis.
22. THE SEARCH FOR TRUTH: FUTURE INSTRUMENTATION
317
A. Suzuki, S. Watanabe, Y. Takeno, T. Kosugi, T. Kasuya, Possibility of detecting decep-
tion by voice analysis, Reports of the National Research Institute of Police Science 26 (1)
(February) (1973) 62–66. Conclusion: Voice measures were not reliable or useful.
Perhaps these outcomes were to be expected. Voice stress is a single-parameter instru-
ment, whereas the polygraph is a three-parameter instrument. If we looked at any single
component of the polygraph, we would find that its accuracy does not compare to the accu-
racy obtained through the synergy of the three parameters.
There are some law enforcement agencies that are employing voice stress as their mode
for truth verification. Unfortunately, this is more likely a poor financial decision rather than
an intelligent choice. To be trained in voice stress takes 5 days. To be trained in polygraph
takes a minimum of 10 weeks. In addition, these agencies report that use of voice stress has
resulted in an increase in information and confessions. We are sure that this claim is true. If
that is the sole goal, however, we suggest they place wires from the suspect to a copy
machine with a paper inside that has “It’s a LIE!” written on it. The admissions and confes-
sions resulting would be the same. This refers to the utility value of the test, not the accu-
racy. Charles Humble, president of the National Institute for Truth Verification, which
manufactures the CVSA, was interviewed on the Primetime television show [2]. During
the interview, Humble admitted that there was no scienti
fic research showing the validity
of the CVSA, only utility-value reports from law enforcement agencies using the device.
He also stated that he received his Ph.D. in psychology after 6 hours of correspondence
study in religion from a school located in the same office building as his company. Unfor-
tunately, although there is a utility value in employing voice stress devices to gain informa-
tion and confessions, if the future of a suspect or applicant is decided based on the accuracy
of the voice stress data collected, it is a sham!
The physiological parameters measured by current and past instrumentation are the end
result of what happens when a person lies. These physiological changes occur only after
the brain perceives the threat and causes autonomic changes to occur to ensure survival.
The search for truth in the future has already begun. It is the ultimate journey into the
human mind.
1
2
3
4
5
6
7
8
9
FIGURE 22.3 Voice stress patterns associated with distress and deception.
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22. THE SEARCH FOR TRUTH: FUTURE INSTRUMENTATION
Searchers for truth have always maintained that deception requires much more cognitive
energy than truth. To tell the truth is a simple process: you report what you believe to be the
facts. Deception is much more difficult. You must first decide to lie, decide what to say,
question whether the information will contradict anything you already said, question
whether it is something that can be verified later as untruthful, and contemplate what hap-
pens to you if you are caught in your lie.
In recent research into the possible use of functional magnetic resonance imaging (fMRI)
with which one of the authors is involved, a possible model for deception was hypothesized
[3]. In Figure 22.4, you will notice that for a truthful person, (1) a question is received; (2) it is interpreted; (5) verbal instructions are received; and (6) the truthful person answers the
question (3a, 3b, and 4 are bypassed). Compare that to the activation sites involved for
the deceiver: (1) A question is received; (2) it is interpreted; (3a) the deceiver must recall
the event associated with the question; (4) judgment and planning is involved, including
inhibition of the truthful answer; at the same time (3b) there are emotions associated with
it; (5) verbal instructions are received; and (6) they answer the question; (3c) at the same
1. Hear or see question presented by examiner
Auditory Cortex (BA 41,42) [1]
Visual Cortex (BA 17,18,19) [1]
Dominant Angular Gyrus (BA 39) [2]
2. Processing and understanding of question
Wernicke’s Area (BA 22) [1]
3b. Fear/Anxiety/Apprehension/Guilt/Joy
3a. Memory recall of event associated with question
Amygdala [1]
Dorsolateral Prefrontal Cortex (BA 46)
[1,5,6]
Via Ventral Amygdala Fugal Pathway and Stria Terminalis
Superior
Longitudinal
Medial Dorsal Thalamus
Fasiculus [1]
4. Judgment and planning of response including inhibition
Orbital and Medial prefrontal cortex (anterior to BA 4 & 6) [1,4,9]
-right hemisphere dominance [3]
3c. Sympathetic Stimulation
Fronto-polar Prefrontal Regions [2]
Hypothalamus
Ventrolateral Prefrontal Cortex [7]
Right Prefrontal Cortex [6]
Sweating (GSR)
Anugular Gyri of Parietal Lobe (BA 39) [2,8]
Pulse (blood flow)
Supramarginal Gyri of Parietal Lobe (BA 40) [2]
Breathing
Superior Frontal Gyrus [6]
Anterior Cingulate [2,3,6]
6. Verbal Response
5. Verbal Instructions
Precentral Gyrus:
Polygraph
Broca’s Area [1]
Motor Areas for muscles
(BA 4, BA 6) [1]
FIGURE 22.4
22. THE SEARCH FOR TRUTH: FUTURE INSTRUMENTATION
319
time sympathetic arousal occurs, finally ending with physiological changes that can be
observed by the interviewer or recorded by the polygraph.
Three areas of exploration into the brain are of importance to this area of research: brain
waves or brain fingerprinting, blood flow changes observable through ultraviolet rays, and
brain activation as mentioned, seen through fMRI.
Dr. Farwell is the innovator of a process of monitoring electroencephalographic (EEG)/
P300 brain waves he has called brain fingerprinting. His testing system determines whether
or not specific information is stored in a person’s memory. The test measures individual
brain-wave responses to relevant words, pictures, or sounds presented by a computer.
Farwell maintains that the fundamental difference between the perpetrator of a crime and
an innocent person is that the perpetrator, having committed the crime, has the details of
the crime stored in his memory, and the innocent suspect does not. Brain fingerprinting
identifies whether the stimulus presented is stored in the suspect’s memory (Figure 22.5).
Farwell reports a high level of accuracy in determining this and has successfully had his test
results entered into court proceedings.
One problem with the process is the very essence of how it works: it requires the inno-
cent suspect to have no knowledge or memory of the event in question. This in itself limits
its use. For example, if you are accused of raping a woman you claimed you never saw, in
her house, where you claim you have never been, then brain fingerprinting, if it is indeed
accurate, could be used because you should have no memory of what the victim or her
house looks like. On the other hand, if you were accused of staying late at work and raping
a coworker, then even if you were innocent, your memories would include the victim and
crime scene, and consequently this testing could not be administered.
At the 2005 annual meeting of the American College of Gastroenterology, in Honolulu,
researchers reported on a study where they measured changes in the stomach using an elec-
trogastrogram (EGG) in sixteen healthy volunteers while they did nothing, told the truth,
or told a lie. The study showed that both lying and telling the truth were associated
with changes in heart rate and stomach activity. The act of lying was associated with a
decrease in the amount of normal gastric “slow waves.” “The addition of the EGG to
standard polygraph methods has clear value in improving the accuracy of current lie detec-
tors,” stated researcher Pankaj Pasricha, MD, of the University of Texas Medical Branch.
FIGURE 22.5 (A) Information “not present.” (B) Information “present.”
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22. THE SEARCH FOR TRUTH: FUTURE INSTRUMENTATION
“The communication between the big brain and the little brain in the stomach can be com-
plex and merits further study.”
Another new attempt at lie detection uses high definition thermal imaging cameras that
can detect thermal pattern changes [4]. Thermal imaging cameras enable rapid analysis of
changes in blood flow around the eyes. The camera is used to image a suspect’s face while
he is being questioned (Figure 22.6).
A recent laboratory study using the device showed it to be 78% accurate, having a 5%
false positive rate (truthful suspects erroneously determined deceptive) and a 17% false
negative rate (deceptive suspects erroneously determined to be truthful).
Although this instrumentation can be employed covertly and is much less restrictive
than the polygraph, accuracy rates are much lower. In addition, the authors believe that
the intensity of being stopped and interviewed at an actual checkpoint would greatly
increase the intensity of actual suspects, creating “real life” results with less deceptive sus-
pects being erroneously classified as truthful, but more truthful suspects being erroneously
classified as deceptive.
More recently, a study performed at Temple University in Philadelphia showed that
when people lie, they use different parts of their brains than when they tell the truth. These
changes were identified through the use of fMRI [3].
The researchers created a relevant situation for eleven normal volunteers. Six of the
volunteers were asked to shoot a gun with blank bullets and then to lie about their partici-
pation. The five nonshooters were asked to tell the truth about the situation. The researchers
examined the individuals with fMRI as well as administering a polygraph examination uti-
lizing a computerized system measuring thoracic and abdominal respiration, blood pres-
sure, and galvanic skin conductance.
The volunteers were asked questions that pertained to the situation, along with unrelated
control questions. In all cases, the polygraph and fMRI accurately distinguished truthful
responses from deceptive ones. The fMRI showed activation in several areas of the brain
during the deception process (Figure 22.7). These areas were located in the frontal (medial inferior and precentral), temporal (hippocampus and middle temporal), and limbic (anterior and posterior cingulate) lobes. During a truthful response, the fMRI showed activation
in the frontal lobe (inferior and medial), temporal lobe (inferior), and cingulate gyrus.