who taught the authors the true meaning
greatly appreciated.
of love.
The authors would be remiss if they did
The authors wish to dedicate this book in
not express their everlasting gratitude to
memory of Lee G. Feathers, a member of the
their loyal wives, Kathy Gordon and
first graduating class of the Academy for
Michelle Fleisher, and their families, who
Scientific Investigative Training. Lee went
have endured many lonely hours support-
on to become one of the finest polygraph
ing their careers.
examiners and interrogators in the north-
Over the years, the authors have had the
eastern United States—thanks, Lee, for your
distinct pleasure of meeting and training
friendship and insight into interviewing
some of the finest individuals from all over
and interrogation.
xiii
Companion Web Site
Ancillary materials are available online at:
www.elsevier.com/companions/9780123819864
xiv
C H A P T E R
1
The Search for Truth
The need to detect deception is hardly a twentieth-century phenomenon; humans have
always needed to distinguish between the trustworthy and the untrustworthy. Agreed, to
some small extent there is an inherent conflict in that both truth and deception have their
places: they are necessary for individual and social survival. There are times when truth
serves a socially destructive purpose or when small truths aren’t useful in a larger context.
However, in the great majority of cases, deception is used to hide or disguise the truth to
the detriment of society. The question is, how can we separate harmless lies from harmful
ones and, more to the point, harmful lies from necessary truth? Those for whom the lies are
useful work against solving the problem. They know that for the lie to do its job, it must not
be detectable—or, at least, not detectable before escape or attack is possible.
Ever since small familial groups of humans banded together for mutual social benefit, or
for protection of person and property, humankind has been plagued by individuals whose
practices deviate from the societal covenant. The activities of these individuals, if not
checked, could and sometimes did destroy the societal group as a whole. Given that, the
ability to detect lies to identify individuals who cannot be trusted has been vital to both
physical and social survival. The search for a reliable means to identify the untrustworthy
is as ancient as humankind. Some techniques were founded in superstition and/or the reli-
gious belief that a moral god would in some way reveal the truth and disallow immorality.
Many of these attempts, in fact, had some psychological or physiological basis; other meth-
ods relied solely on fear of continued pain and torture.
What is interesting about human behavior is that it has not changed since Biblical times.
In fact, the very first clue to human behavior appeared in the Book of Genesis. It is the story
of Eve influencing Adam to eat the fruit of the forbidden tree. Having eaten it, Adam and
Eve were imbued with knowledge and realized they were naked. When they heard God’s
voice, they were ashamed and hid themselves. God asked Adam why he was hiding. Adam
replied that they were naked and ashamed. God asked Adam how he knew he was naked:
did he eat from the fruit that was forbidden? Adam replied, “The woman Thou gave me
made me eat thereof.” When God asked Eve about that, Eve stated, “The snake beguiled
me into eating the forbidden fruit.” Although the authors are paraphrasing the story, it is
obvious that things have not changed much since the Garden of Eden [1]. Persons accused
almost always look for someone else to blame for their situation. Often, it is the victim they
Effective Interviewing and Interrogation Techniques
1
# 2011, Elsevier Ltd.
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1. THE SEARCH FOR TRUTH
blame. This is an excellent example of how humans rationalize to escape punishment and
conceal the truth.
The earliest form of lie detection probably was trial by combat, resolving an issue
through strength of arms. In primitive hunting tactics, it was not uncommon for hunters
to shoot an arrow or spear into an animal that would only wound it. The hunter would then
track the wounded animal until it died either from loss of blood or from the poison often
used on the arrow tip. Consider the problem of two primitive hunters who approach a
fallen prey. Each believes it was his arrow or spear that killed it, and that it belongs to
him; they refuse to compromise. As simplistic as it seems, each sees himself as making a
truthful claim and the other as not. To decide the “truth,” which actually means possession,
they engage in combat. The ideal assumption is that the individual with truth on his side
will prevail. However, the most cunning and skilled of the combatants usually was victori-
ous and thus declared himself as having the rightful claim.
This scenario had changed very little by medieval times. It was then customary that
knights engaged in mortal combat to decide whose lord was in the right in any given con-
troversy. Although the practice was functionally the same as trial by combat, the ethical
premise was different. It was held that the knight representing the truth would be victori-
ous because of “divine intervention”—that is, that a just God would not allow injustice to
prevail.
Even today, on any given weekend night, a police officer may be called to a club or bar
where two men are about to engage in combat to determine which of them is telling the
truth about whom the woman seated between them is really with. As you can see, the test
of “trial by combat” lives on.
The next development in the search for truth was trial by ordeal [2]. It was once again
assumed that God would intervene on behalf of the innocent; that is, God would protect
any innocent individual from harm, as was the case with Daniel in the lion’s den. Although
these attempts to detect truth appeared to be laden with religious beliefs, they were in fact
based on practical observations of both psychological and physiological phenomena, which
play an important role in truth-finding processes.
For example, in China, in approximately 1000 BC, it was common practice to have an
accused person chew a handful of crushed dry rice, and then attempt to spit it out (certainly
not much of an ordeal) [3]. If the rice became wet, and therefore easy to spit out, the person was considered truthful. If the rice was dry and it stuck to the suspect’s mouth when he
tried to spit it out, then he was thought to be lying. Divine intervention was not involved
in this outcome as much as was the salivary gland. This somewhat benign test was based
on the physiological phenomenon of inhibited salivary gland activity caused by fear or
stress. The truthful individual had normal salivary gland activity, causing the rice to
become wet and easy to spit out. The stressed or deceptive person had a dry mouth, and
the crushed rice in his mouth remained dry and when he attempted to spit it out it stuck
to his mouth. It is unclear ho
w the Chinese arrived at their test for truth—whether they
merely observed that liars’ mouths remained dry, or had some understanding that the auto-
nomic nervous system inhibits salivation and all digestive processes when an individual is
under serious threat. It should be noted that Chinese traditional medicine has been around
for some 5000 years.
1. THE SEARCH FOR TRUTH
3
Interestingly, testing for a dry mouth was, and still is, found in a wide range of unrelated
cultures worldwide. The most severe version of these tests often consisted of putting some
kind of red-hot metal object on the tongue. If the person were truthful, the normal saliva in
the mouth protected the tongue, acting as a “heat sink” to dissipate the burning. If the
person were lying, the mouth would be dry, and the hot metal would burn the unprotected
tongue. Even today, in some countries in the Middle East, it is common that the accused in
minor cases can choose this traditional method to assert his innocence [4].
In various societies, truth tests were developed whose premises were psychological, not
physiological. Trial by the “sacred ass” is a classic psychological test that was practiced in
India around 500 BC [2]. In this test, a donkey was staked out in the center of a pitch-dark hut. The suspects were told that inside the hut was a “sacred ass” that could differentiate
between a truthful person and a liar. It did this by braying only when the guilty (lying) per-
son pulled its tail. They were also told the animal would remain silent if an innocent (truth-
ful) person pulled its tail.
Each suspect was directed to go into the hut alone, with specific instructions to pull the
tail of the “sacred ass.” What the suspects did not know was that the priests had covered
the donkey’s tail with lamp black. A truthful individual, having nothing to fear, entered
the dark hut and pulled the donkey’s tail. The donkey may or may not have brayed, but
those who were innocent came out with soot all over their hands. A guilty party, on the
other hand, would enter and, not wanting to risk disclosing his guilt, would not touch
the donkey’s tail. He might promise it a carrot, or stroke its head, but he would not pull
the tail. After all, he believed if he did not touch the tail of the “sacred ass,” it would have
no reason to bray, and the priests would incorrectly identify him as truthful. The elegantly
simple truth was that because he did not pull the tail, it was easy for the priests to properly
identify him as the culprit by his clean hands.
In the 1950s, rumors have it, the Philadelphia Police Department had a detective division
that innovated an interesting psychological test for truth. The suspect was seated in a chair.
One detective stood behind him holding a thick telephone book; the other one stood
directly in front of him. The latter detective informed the suspect that he was going to
ask him some questions, and as long as he answered questions truthfully, there would be
no problem. The suspect was also told, however, that if he lied, the detective standing
behind him would hit him in the head with the telephone book. “It won’t leave any marks,”
he was told, “but it will hurt like hell!” The detective would then begin with some irrele-
vant questions: “Is your name James Smith?” “Were you born in Pennsylvania?” “Do you
reside at 412 Mercy Street?” Then the detective would ask a strong relevant question:
“Did you steal that missing deposit?” and they would observe whether or not the suspect
flinched or ducked as he answered the question, indicating he anticipated being hit with
the phone book because he was lying. This was an involuntary reflective reaction that
would only occur when a person knew he was lying and anticipated being hit.
Society’s next advancement in its search for truth was trial by torture. This had a dichot-
omous effect for law enforcement. Every crime could be solved by confession; unfortu-
nately, it was not always solved by identifying the actual perpetrator of the crime! The
assumption was that the innocent suspect would withstand any amount of suffering to pre-
serve his reputation and, in religious societies, his immortal soul. In reality, given enough
4
1. THE SEARCH FOR TRUTH
pain, any man might confess, and most torturers knew that. The “trial,” in fact, became
indistinguishable from the punishment itself and was justified in that the “truth seekers”
found almost everyone guilty. Trial by torture was the method of justice during the infa-
mous witch hunts and inquisitions in Europe.
These latter are of particular interest, because they did not have as their basis the seeking
of truth. Rather, the method addressed a perceived threat from forces whose existence
could not be proven. Thus, trials by torture were not always designed to find truth, but
sometimes to justify and validate the prejudices and fears of the society and the claims of
its leaders. Such “trials” were commonplace during the Middle Ages and the Renaissance
and continued into more recent periods when people believed that witches or some other
group (e.g., Jews, Communists, reactionaries, homosexuals) threatened the social order.
In the past, there were two ways in which an inquisitor attempted to prove a person was
a witch [5]:
1. By finding the “Devil’s Mark,” or
2. By getting a confession.
The Devil’s Mark was an alleged spot on a witch’s body that showed she had been
attached to the Devil (much as we have a navel where we were once attached to our
mothers). Although the Devil’s Mark was invisible, it could be found because it was a spot
on the witch’s body that would not bleed. Suspected witches were tied down and continu-
ously pricked as the inquisitors searched for the spot. It is not known how many witches
were discovered by finding the elusive mark; however, many “witches” confessed during
the process. Unfortunately, trial by torture is still used today to solve “crimes” by confes-
sion, the solution of the crime being of greater importance than whether the suspect is
guilty or innocent. This was unfortunately demonstrated when treatment of detainees
and prisoners at Abu Ghraib and other holding areas by United States interviewers and
interrogators was revealed [6]. More about torture is found in Chapter 14 of this book.
As civilized societies searched for a more just and credible way to separate the innocent
from the guilty, trial by torture lost credibility and was replaced by trial by jury. Although
the jury in its early form was not made up of one’s peers, it is the origin of our judicial sys-
tem in which the “Finder of Fact,” either a judge or a jury of peers, listens to evidence intro-
duced by witnesses. The Finder of Fact then decides the defendant’s guilt or innocence
based on some standard of proof.
As is still the case in our current judicial system, this involves the evaluation of objective
facts—that is, data that can be confirmed physically—and the testimony of competent wit-
nesses and experts. The latter involves the subjective interpretation of the witnesses’ credi-
bility and/or expertise by the judge or jury and, among other things, is subject to
manipulation by a clever liar. Although the jury system
proved more humane and more
just, the Finder of Fact’s inability to separate truth from deception in complex cases leaves
it seriously flawed.
The infamous Dreyfus case, in which a Jewish-French army officer was falsely convicted
by fabricated evidence and a prejudiced court, focused attention on the need for a better
means of detecting liars and their fabrications. That need was experimentally addressed
in a series of scientific attempts beginning in late nineteenth-century Europe. By this time,
the scientific community had a basic understanding of the autonomic nervous system.
1. THE SEARCH FOR TRUTH
5
Scientists understood the physiological changes that occurred in the human body caused by
fear and stress and correctly assumed that those changes would occur when a suspect expe-
rienced the fear of being caught in a lie. The research centered on finding a reliable and
timely means of measuring those changes.
In the early 1890s, Angelo Mosso, an Italian physiologist, studied the effect of fear on the
cardiovascular and respiratory systems. Mosso was particularly interested in measuring cir-
culatory flow changes in the body. He developed a mechanical device known as the “Scien-
tific Cradle,” often called “Mosso’s Cradle.” This device was nothing more than a balanced,
table-like platform, mounted on a fulcrum [2].
Mosso theorized that the flow of blood to the head changes during emotional stress, such
as that caused by fear of detection. This, he believed, explained why a person’s face flushes
or whitens during emotional states. He theorized that this sudden change of blood flow to
the brain caused by fear would result in a slight shift in the subject’s body weight, and thus
a corresponding measurable movement of the cradle.
Mosso proposed he could analyze the lines drawn on the kymograph and determine the
credibility of the witness. There is, however, no evidence that Mosso ever put his theory
into practice. In all probability, the device was too crude and unreliable to make the kind
of measurements that Mosso would have needed.
In 1895, Cesare Lombrosso, an acquaintance of Mosso, applied the use of more precise
instrumentation sensitive to changes in volumetric displacement to measure emotional
Nathan J Gordon, William L Fleisher Page 2