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FORENSIC
CRIMINOLOGY AND PSYCHOPHYSIOLOGY
Truth
Verification tools, with a special study of Truster
Pro.
Drs.
Guy van Damme
Former
Associate Professor - University of Durban Westville
1.
Introduction/Background
In 1997, I was
asked by Prof. A. Padayachee, to develop a module of Forensic
Criminology for the University of Durban Westville, one particular
chapter being "Investigative tools", meaning all Truth
Verification techniques. As a long practising polygraph operator,
qualified in forensic psychophysiology in 1982, I was asked by
Trustech Israel, to analyse their latest product, the Truster Pro.
It soon became
clear that this knowledge should not be restricted to the academic
world but be made available to the real practitioners in the field.
To share my knowledge of Truth Verification tools and the Truster
Pro in particular we composed this article. I hope you enjoy it.
This paper is
directed at people involved, or merely interested, in the fight of
crime.
The purpose is to
provide or to improve the basic knowledge of "Truth
Verification" needed by any investigator.
Certain
techniques and different methods of Investigative tools will be
discussed enlarging on the newest tool, the Truster Pro without the
intent of neglecting or degrading the other excellent tools, such as
the well known and proven polygraph.
2.
Investigative Tools, Truth Verification Techniques
2.1
Introduction
Mankind,
throughout history, has sought and found ways and means of
separating truth from deception.
The science of
truth verification however, based mainly upon psycho-physiological
analogues, is barely one hundred years old.
Many stories of
inventive procedures have been carried over from the past.
One ancient
legend mentions a method employing the tail of a donkey.
The donkey was
placed in a darkened tent and its tail was then generously coated
with lampblack.
All possible
suspects were then asked, one after the other, to enter the tent and
pull the donkey's tail.
They were told
that the donkey would only bray if a liar pulled his tail.
The honourable
men obviously having nothing to fear did indeed pull the donkey's
tail and came out of the tent with their hand blackened with
lampblack.
The liar however,
afraid of the fact that the donkey would indeed bray, did not pull
the tail and reappeared from the tent with clean hands.
An interesting
technique stemming from ancient China is the following:
When subjects
were interrogated, they were given a small amount of dry rice, with
the instruction to keep the rice under the tongue.
After the
interrogation, he had to spit out the rice in his hand.
The fortunate
people whose rice was wet by saliva could keep their head. The
person whose rice was still dry lost it.
The theory comes
down to a well-known phenomenon: the mouth goes dry when under
stressful conditions.
The middle ages
in western Europe, followed by the dark times of the Inquisition,
used methods not to be proud of: hot irons, iron maiden, the wheel,
burning at the stake, dunking etc. Ironically, they have proven to
be the least effective.
From these
ancient records until today, many techniques and methods have been
invented and tried to ascertain truth and lie, deception or
non-deception, right or wrong.
Sometimes based
upon pure psychological methods, sometimes purely mechanical,
sometimes a combination of both, they all come down to the basic
need of knowing the real facts.
The great
breakthrough came at the end of the 19th century (1893) when the
well known "father of criminology" Cesare Lombroso started
experimenting with pulse and blood pressure changes in order to
establish verification of truth in answers given to questions by
actual criminal suspects.
The idea of using
the pulse as a truth verification technique was older than that, but
Lombroso and his student Angelo Mosso were the first to actually use
a physical device to demonstrate the changes in pulse and blood
volume and to scientifically document the findings.
Already in the
middle ages it was related that the pulse was used as an
investigative tool.
A nobleman
suspected his wife of infidelity and informed his advisor of this.
The advisor
arranged a test during a dinner party at which he was seated next to
the nobleman's wife.
While conversing
he casually laid his hand on the wrist of the lady and mentioned the
name of the person suspected by the nobleman.
The lady's pulse
suddenly quickened while it had not when mentioning her husband's
name. A confession was later obtained.(Gesta Romanorum 1906).
In 1730, just
before he died, Daniel Defoe wrote an essay called "An
effectual Scheme for the Immediate Preventing of Street Robberies
and Suppressing all Other Disorders of the Night".
Defoe claimed
that taking the pulse rate of a suspect is a practical, effective
and more human method of determination of deception.
"Guilt
always carries fear around with it, there is a tremor in the blood
of a thief, that, if attended to, would effectually discover him,
and if charged as a suspicious fellow, on that suspicion only I
would always feel his pulse, and I would recommend it to practice.
The innocent man which knows himself clear and has no surprise upon
him; when they cry "stop thief" he doesn't start; or
strive to get out of the way; much less does he tremble and shake,
change countenance or look pale, and less still does he run for it
and endeavour to escape."
Defoe went on:
"It is true
some are so hardened in crime that they will boldly hold their
faces, carry it off with an air of contempt, and outface even a
pursuer; but take hold of his wrist and feel his pulse, then you
shall find his guilt; confess he is the man, in spite of bold
countenance or a false tongue...a conscious heart will discover
itself by faltering pulse..."
It may be true,
that this discovery by the pulsation of the blood cannot be brought
to a certainty, and therefore it is not to be brought into evidence;
but I insist if it be duly and skilfully observed, it may be brought
to be allowed for a just addition to other circumstances, especially
if concurring with other grounds of suspicion (Scott-Kilvert
1965; Ansley 1989).
Mosso, with
strong encouragement by his mentor Lombroso, used for his research
on emotion and fear during questioning and their influence on cardio
activity and respiration, a "plethysmograph".
This instrument,
developed by Francis Franke measures blood pressure and volume.
The use of it
revealed periodic undulations in blood pressure caused by the
respiration cycle.
Mosso was the
first scientist to report that the breathing pattern changes under
certain stimuli.
He also reported
that variations in blood pressure and the circulation of blood
during fear are greater than those resulting from mere noise and
sound.
Mosso's mentor,
Cesare Lombroso actually applied Mosso's experimental blood pressure
and pulse tests to actual criminal suspects on several occasions.
In his second
edition of L'Homme Criminel (published 1895) Lombroso describes his
experimental use of the plethysmograph and spygmograph during
interrogations.
Scientific
research towards truth verification thus started as an academic
discipline.
The military
forces (with greater budgets than police forces) quickly became
aware of the importance of reliable truth verification techniques
(or better, procuring information from unwilling subjects) and
engaged in their own research.
Dr. Charles E.
Cady, a U.S. military surgeon, observed Rebel officers divulge
important information whilst under the influence of chloroform.
Although not
involving himself in the practical application, he strongly
recommended that skilled anaesthetists should administer pure
chloroform to subjects in a well-ventilated room and, whilst the
subject is semiconscious, interrogate him bluntly and pointedly (Eisenschiml,
1940).
Further
developments in scientific truth verification at the end of the
previous century came from F. Galton, who developed the word
association test and Wilhelm Wundt, the founder of the first
psychological laboratory in Leipzig, Germany.
Wundt modified
Galton's association method to a standardised form, still in use.
Adamkiewicz's
experimental proof that the secretion of sweat is closely linked to
psychological processes, lead Sticker to experiment with the
galvanic skin phenomenon and the development of the first
psychogalvanometer.
The three
essential components of the modern polygraph had now been developed,
together with the knowledge of word association and hypnotics (truth
serum).
Arthur MacDonald
can be described as the first person to propose the development and
the creation of an apparatus combining the three systems: pneumograph,
psychogalvanometer and cardiospysmograph.
The polygraph was
born.
Hundreds of
scientists from then on worked on the development of polygraph, word
association and so called truth serums.
In 1964, Charles
R. McQuiston made a new step in the truth verification research.
The U.S. Army
desired a alternative instrument to the polygraph with no need for
direct connection to the subjects body, one of the main
disadvantages of the polygraph.
He coined the
name "voice stress analysis" and together with two retired
friends, Wilson Ford and Alan Bell, he developed the first prototype
of his "Psychological Stress Evaluator".
The PSE relied on
measuring stress-induced changes to the "muscle
micro-tremor" as displayed in involuntary changes in the voice.
In less than one
century the science of truth verification developed four main
techniques and instruments, the polygraph, the voice stress
analysis, psychological profiling and truth serum.
2.2
Polygraph
2.2.1
Scope
The scope of this
document is to give you the essential facts about polygraph testing,
in order to give you the basic understanding of what happens if you
consult a polygraph examiner, what he can and cannot do and to make
a right choice to consult him or one of his colleagues using a
different truth verification technique.
2.2.2
Underlying principles.
The term "
POLY-GRAPH" means literally " Multiple Writing" (from
the Greek Language).
The name is now
often connected to the term " Lie Detector" or as "
an instrument for recording of several different pulsations (as of
physiological variables) simultaneously" (Encyclopaedia
Britannica).
The name was
derived from the fact that the polygraph, as opposed to, for
example, the GSR or VSA which only record one reading, looks at
various selected physiological activities.
Human beings (as
well as any other mammals and most other living beings) are endowed
with a very sophisticated survival mechanism.
Their whole well
being depends on the maintenance of an inner balance, fluids and
chemicals, throughout every organ in the body.
This balance is
called homeostasis.
In the centre of
the brain is a gland called the Hypothalamus: our internal
regulator.
All our
unconscious activities such as sleep, breathing, digestion, pulse,
blood volume, respiration etc. are regulated by the autonomic
nervous system, controlled by the hypothalamus.
When our well
being is threatened, physically or psychologically, one of our
sensors, hearing, seeing, feeling or even instinct, will send alarm
signals to the autonomic nervous system which will activate its
sympathetic department and take action.
When the ear of
the subject receives a potentially threatening message from the
examiner, this stimulus is transferred via sensory neurones to the
temporal lobe of the cerebrum.
Regarding
treating the nature of the stimulus the signal is send to the
frontal lobe (the centre for judgement and reasoning) where the
question is perceived and a judgement made.
If the question
is perceived as threatening, the alarm is sent from the frontal lobe
through the hypothalamus to the sympathetic system which will then
take appropriate action nl. a sympathetic response.
(Note that this
whole process cannot even be calculated in microseconds, it is semi
instantaneous).
The body is now
programmed for " fight or flight" mode.
The adrenal
medulla glands will extract adrenaline (hormones known as
epinephrine and norepinephrine) so that certain bodily functions
will alter in order to stand the best chance to survive the
emergency.
For example, the
blood will be instantly distributed to the most important areas like
the brain and the larger muscles, and in other parts the arterioles
will constrict, preventing blood going to where it is not needed.
Other very
obvious effects will take place, known by all of us:
* The mouth gets
dry, due to the salivary glands producing much thicker saliva.
* The heart pumps
harder and faster, thereby increasing blood volume and pulse.
* Stimulation of
the respiratory muscles leads to breathing changes.
* The sweat
glands are stimulated and forced to release perspiration.
* The iris of the
eye dilates permitting more light into the eye.
* The anal and
urinary sphincters contract and the bladder relaxes.
* Involuntary
muscles contract.
While the
sympathetic system organises this whole defence system in next to no
time, the parasympathetic system, functionally antagonistic towards
his partner, follows up in order to re-establish the chemical
balance of the body.
Without these two
antagonistic partners, the defence system of the body would go into
a high build up and cause damage to the body (E.g.. burst artery in
brain). The two of them are essential to maintain a perfect
homeostasis.
All of the above
mentioned physiological activity can be measured.
As Dr. James A.
Matte puts it:
"The
forensic psychophysiologist (the polygraph examiner) measures
and records
breathing patterns, heart beat, pulse rate and strength,
changes in mean
blood pressure, and electrodermal responses in
order to obtain
physiological evidence of hypothalamic activity
including the
sympathetic and the parasympathetic subdivisions of
the autonomic
nervous system during the psychophysiological
veracity
examination ( polygraph examination) on the test."
(J. A. Matte
1996, Forensic Psychophysiology using the Polygraph)
The "
Introduction" briefly outlined the various stages of history of
the polygraph and explained that three basic scientific techniques
had to be developed before the first real polygraph was created.
The polygraph
collects physiological data from at least three systems of the human
body:
* The respiratory
system: the examiner will record " thoracic breathing" and
" abdominal breathing".
Convoluted rubber
tubes are placed over the chest and the abdomen.
* Galvanic skin
response (electrodermal).
Two small metal
plates are connected to the fingers (normally the middle section of
the index and ring finger of the left hand). These plates record the
filling up of sweat glands (empty during homeostatic condition) and
the nearly immediate reabsorbation of the moisture.
* The Cardiac
system: the examiner will record Blood volume and Pulse rate.
A medical blood
pressure cuff containing a rubber bladder is wrapped around the
upper right arm, against the brachial artery. The cuff is connected
via the instrument (cardiosphygmograph) to a hand pump with a
pressure indicating gauge.
* Certain systems
(e.g. Lafayette) offer an option where the examiner can measure
minor movements induced by the contraction of involuntary muscles.
These five
(thoracic and abdominal breathing, blood volume, pulse rate and
galvanic skin response) or six (movement) readings will be recorded
on "Chart" (see later). Normally the examiner will do
three to four charts.
From these
charts, the examiner will do his calculations (manually or with
computerised systems via his software), make his decision and file a
report, which goes to the client.
2.2.3
The Polygraph examination.
2.2.3.1
General.
The typical
polygraph examination consist of three distinctive parts:
* the pre test
interview
* the actual
examination or chart collection phase
* the test date
analysis phase
2.2.3.2
The pre test interview
Most people do
not really realise that in fact, the most important and often the
longest phase in a polygraph examination is the pre test interview.
While the average
test will take approximately 90 minutes, the pre test
interview can
easily absorb 45 minutes in general.
During the pre
test interview the examiner will:
* Talk nicely
with the subject and do his best to put him / her at ease.
* Will give the
subject a detailed explanation of what is going to happen during the
actual
testing phase and
confirm his understanding.
* Will define the
subject's legal rights.
* Explain to the
subject what the polygraph is all about and how it
works (briefly)
* Write down all
the subject's details in order to make the identification sheet
attached to the
report.
*Ask certain
questions about the subject's health, if he has eaten over the last
5 - 6 hours, if he had a good nights rest and is not to tired.
* Talk about the
"incident" or "issue".
* Discuss all the
questions which will be asked and make sure the subject answers them
all
confidently and
understandingly.
* Ask the subject
one last time if he is prepared to undergo the test and then invite
him to take
a seat in the
interviewing chair.
The examiner will
then connect the different components to the subject whilst asking
him to sit absolutely still during the whole time of each chart
recording (approximately 4 to 5 minutes).
2.2.3.3
The actual polygraph examination.
Before the pre
test interview, the examiner had a briefing with the client, which
will typically be the investigator but, in certain cases, can be the
subject himself.
During this
briefing, the examiner has to make up his mind as to which type of
questionnaire he will be using (see later). Depending on the type of
test he will draw up a specific questionnaire, discuss the relevant
questions (see later) with the client and, on his approval, go to
the interview room (see later) to start his pre test interview.
2.2.3.3.1
The interview room.
The ideal
interview room is not too small, not too big (3,5m X 3m). It should
be guaranteed have privacy with no possibility of interference (no
telephone).
The furniture has
to be sober but adequate: desk and chair for the examiner, normal
chair for the subject and a chair for the test itself. This last
chair has to be really comfortable, has to have large and long
enough armrests in order to give the subject the easiest means to
sit still during the chart recording.
Psychological
research has indicated that the most relaxing colour for the walls
is with a very light hint of purple mix. This colour seems to subdue
the subject and leads easier to confessions.
2.2.3.3.2.
Question types.
In the different
types of test questionnaires which will be discussed
later, three
different types of questions will be used.
* Irrelevant
questions.
Irrelevant
questions are essentially questions, which will give the examiner a
truthful answer. It is generally a "Yes" answer.
Examples:
- Is today
__________________?
- Is your name
_____________?
- Are you sitting
in a chair?
- Were you born
in _________?
The irrelevant
question gives the examiner a good idea how the subject reacts when
being truthful.
It also allows
the parasympathetic system to bring back homeostasis.
* Control
questions.
The control
questions are questions on which all subjects will be potentially
untruthful. They are used to absorb any anxiety of a truthful
subject and draw the attention away from the relevant questions.
The control
questions are so designed that they will draw a possible lie from
the subject to items broadly similar to the issue on hand.
The reaction to
the control questions will be compared to the relevant questions in
order to give a result.
Examples of
control questions:
- Before this
year, did you ever steal anything in your life?
- Before this
year, did you ever lie to someone who trusted you?
- Do you remember
if you ever stole anything from a place where you
worked?
- Do you remember
ever seriously lying to any of your colleagues?
The question is
typically a "No" question. When the subject says yes to a
question, which asks if he ever stole anything, the examiner will
quietly ask what he stole. Most subjects will then say, "small
things" or mention a few neglectable items. The examiner will
then rephrase:
Apart from what
you told me, did you ever steal anything else in your life?, which
will then result in the desired "No" answer.
* Relevant
questions
The relevant
questions are the questions of which the examiner wants a result.
These are the questions which only the subjects knows the truth
about and is the reason for undergoing the test.
The question must
be phrased to engage the subject to say "No". If for
example we want to solve a dispute between X and Y where X says she
gave Y a cheque and Y says she never got it we will ask X :
- Did you give Y
the cheque we discussed?
X will say
obviously say "Yes" while we want "No".
The examiner will
retract a "No" answer by formulating the question as
follows:
- Did you lie
when you told me you gave Y the cheque we discussed?
Now we get a
"No" answer.
The relevant
questions are split up in 4 categories (e.g. theft of car):
- Primary
Involvement: Did you steal that car?
- Secondary
Involvement: Did you help anybody to steal that car?
- Guilty
Knowledge: Do you know who stole that car?
- Evidence
Connecting : Did you get any reward coming from the
theft of that
car? or : Do you know where that car is at present time?
These four
different questions are called " the four legs of the crime:
" Did you do it, did you help, do you know who did it, did you
get anything out of it".
2.2.3.3.3
Type of tests.
Various and
different types of test questionnaires have been developed during
the history of the polygraph. We can not go through all different
techniques but will only discuss the three most used tests as today.
Excellent documentation of all possible test questionnaires can be
found in the recommended reading list, especially S. Abrams and J.
Matte.
* MGQT.
The Modified
General Question Technique ( MGQT) is a modified version of the Reid
technique developed by the famous John E. Reid in 1953.
The difference is
in the strict structuring of the test. No changes on the order of
Irrelevants, controls and relevants are allowed. It is a test
adapted in most computerised scoring algorithms.
The test involves
the four legs of a crime as mentioned above.
The structure of
the test is as follows:
- 1. Irrelevant
- 2. Irrelevant
- 3. Relevant:
Secondary involvement
- 4. Irrelevant
- 5. Relevant:
Primary involvement
- 6. Control
- 7. Irrelevant
- 8. Relevant:
Guilty knowledge
- 9. Relevant:
Evidence connecting
- 10. Control
* ZCT
The Zone
Comparison Technique stems from Baxter, one of the great
researchers in
polygraph techniques. Although originally designed as a
S.K.Y technique
(Suspicion, Knowledge, You (did you)) he later used it as a
technique using three relevant questions, three controls and four
irrelevants concentrating with the relevants on only one leg of the
four legs of the crime.
The structure of
the test is as follows:
- 1. Irrelevant
- 2. Irrelevant
- 3. Irrelevant
- 4. Control
- 5. Relevant
- 6. Control
- 7. Relevant
- 8. Irrelevant
- 9. Control
- 10. Relevant
* RANKING
In a ranking test
all questions are relevant. It is typically used to identify other
people's involvement in a particular case or to locate where the
missing goods are.
It will go as
follows:
- Is Mr. X
involved in this incident?
- Is Mr. Y
involved in this incident?
- Is Mr. Z
involved in this incident?
Ranking is
extremely useful in investigations where one subject has been
directly linked to the crime and to find out who his/hers
accomplices can be.
Example:
An armed robbery
took place at a wage pay out office of a certain company. Thirteen
staff members were present. The robbers (three) got away with
R138.000,00.
All thirteen
staff members had to come for polygraph testing regarding the
involvement in the robbery (handing out information to the robbers
as to when, where, how etc.)
A ZCT test was
done on all staff members.
A lady cashier
was found deceptive regarding her involvement in the armed robbery.
It was then
decided to do a ranking regarding which robber she had spoken to.
The questions
were all: " Was your "brother, sister, mother, father,
boyfriend,
etc." involved in the robbery we discussed.
The result
pointed to her brother.
The next
ranking's objective was to determine where the money was being kept
at that time.
The questions
were: " Is the money at your " mother's, brother's,
boyfriend's, etc" house?
It again pointed
to the brother's house.
The last ranking
went through the brother's house:
Is the money in
the " garden, garage, bathroom, ceiling, etc." of your
brother's house?
The test
indicated the bathroom. After having given this information to the
police, they reported 40 minutes later that they had indeed found
the money under the bath in the bathroom of her brother's house.
Case was closed
two days after the robbery took place.
* Other tests.
- Stimtest: A
ranking where the person picks a card or number and will be asked to
lie when asked if he picked that certain number. Used as a
relaxation technique in pre test interviews or as a demonstration.
* Pre employment
interviews
Often used for
important or high-risk employment. The technique used is Relevant/
Irrelevant whereas the irrelevant questions, when scored as ranking,
should score higher than the relevant ones.
2.2.3.4
Scoring
The actual
scoring of the test is a profession. We will not go into any detail
since the investigator has to rely on the skills of the examiner.
The computerised
polygraphs use scoring algorithms. The most renowned software is
called "Polyscore" and was designed by the "Applied
Physics Laboratory" of the "Johns Hopkins
University".
2.2.4
Who uses the polygraph?
The polygraph
daily becomes more and more popular in RSA.
At present the
USA, Israel, Russia and Japan are probably the biggest users,
although 77 other countries are also known as being frequent users
of the polygraph for various applications.
The polygraph is
obviously mostly used in investigations:
Crime
investigators (private or official)
Fraud
investigators, Insurance companies etc.
Another popular
use is involved in pre employment screening and honesty maintenance
checks.
Attorneys often
use it in civil litigation.
The private
sector often requires it for matters not involving the legal or
criminal justice system.
In certain
countries the polygraph is generally used as a tool to control and
check people on parole.
2.2.5
Is the polygraph admissible in court?
In certain
countries and certain states of the USA, yes.
In South Africa,
no real status has been given to the validity of a polygraph test as
evidence in court.
One Magistrate's
court (Booysens) once accepted (1996) two polygraph tests as
evidence, but since then no other case has been reported, as far as
the author is aware.
The CCMA at
certain times ruled in favour of the employer due to a polygraph
test done on one of their employees, but rejected the test just as
often.
The polygraph
test remains an investigative tool mainly and has to be viewed
purely as that.
It is our opinion
that any evidence delivered in court has to be foolproof and not one
investigative tool such as truth verification test can claim to be
100%.
2.2.6
Training available for polygraph operators.
In the RSA,
training was available through a pilot school in Midrand, but our
correspondent stated that too much problems arose about
accreditations.
The University of
Durban Westville is in the process of developing a BA Honours
module, which will enable BA Criminologists or Psychologists to
fully qualify as Truth Verification Experts.
In the USA
several Universities offer training courses on an academic level
comparable to BA Honours.
Private
institutions can be found through the APA (American Polygraph
Association) which offer Certificates at non-academic level.
Matte (Forensic
Psychophysiology using the polygraph; 1996: 671) however states that
the training of polygraph should be restricted to persons who have
already obtained a degree at a minimum level of a BA.
Israel, Japan,
Russia, Belgium, the Netherlands, France, Germany and Italy all have
Universities offering Polygraph qualification at Honours or Masters
level (no private colleges known to the author).
2.3
VOICE STRESS ANALYSER (VSA).
2.3.1
Underlying principles
In 1964, Charles
R. McQuiston made a new step in the truth verification research.
The US Army
desired to obtain an alternative instrument to the polygraph with no
need for direct connection to the subject's body, one of the main
disadvantages of the polygraph.
The instrument
was to be "a remote lie detector" with a concept based on
recognition that emotional stress induces measurable change into the
human voice.
All VSA's rely on
measuring stress-induced changes to the "muscle
micro-tremor" as displayed in involuntary changes in the voice.
These changes can be found in a tremor associated with contraction
of muscles, effecting minute oscillations at a frequency of about
ten to twelve Hertz (cycles per second).
The amplitude of
these oscillations is a fiftieth or less of that of the total
contraction.
Although all
muscles do exhibit this tremor, the voice stress analyser will only
take into regard those associated with the human voice.