A (brief but exciting) history of lie
detectors
Lies are inherent in all living things.
Let me clarify. By that, I don't mean that I
just broke up with my boyfriend and now I'm going to go write a poem about the
cruel deceptiveness of mankind ("The truth is dead, and black roses wilt in
the betrayed jail cell of my soul"). Not remotely.
What I mean is that deceptiveness is one of
the most commonly used survival tactics. Remember that moth that your third
grade teacher was so excited about? The one whose wings looked exactly like tree
bark? Well, camouflage is just a very basic form of deception. And as I'm sure
you're aware, it's common enough in nature - I would like to draw the reader's
attention to rabbits that change color with the seasons, the praying mantis, and
high school.
In any case, because lies are such a fundamental part of
nature, including human nature, people have trying for thousands of years to
develop a way to determine when someone is being deceptive.
The first lie detector tests were more physical than
psychological. In order to detect lies, they had trials by ordeal, or tests of
physical strength and endurance. Some of the more common trials by ordeal
included one-on-one combat (the innocent man would, of course, be stronger in
battle), and tests to determine how long the accused could immerse his arm in
boiling water. Another favorite involved cutting the accused, and then carefully
dressing the wound and setting a 'heal by' date. If the wound hadn't healed by
that time, the accused was considered guilty. Time to break out the Neosporin,
boys.
Later on, more psychological tests were developed. One, used
by the Hindus, required the accused to chew a mouthful of uncooked rice and then
try and spit it onto a leaf. If the rice stuck to the inside of the person's
mouth, they were considered to be guilty.
The Roman Catholic Church developed a similar type of lie
detector specifically for those members of the clergy who were thought to have
misbehaved. Not that members of the clergy have ever misbehaved. For this test,
the accused priest was made to eat cheese and bread in front of a number of
other priests. If the priest wasn't able to swallow his cheese and his bread,
then it was assumed that God had personally reached down and stopped the food in
the priest's throat in order to indicate deceptiveness.
Now, the reason that these lie detector tests worked (and I
use the word 'worked' in the loosest possible sense) was fairly straightforward
- they detected nervousness. When a person gets nervous, their mouth gets dry.
And when their mouth gets dry, rice and/or a cheese sandwich sticks to it. So
what these early lie detectors were actually detecting was fear, and not guilt.
The first real polygraph test was developed in America in the
early 20th century. A police officer named Larson invented what is rather
wordily referred to as a 'continuously recording interrogation polygraph' in the
1930's. In short, what that means is that he made a device that drew several
graphs at the same time. He also developed what is known as the R/I method,
which I will get to a little bit later.
When lie detectors are used
The most common use of the modern
polygraph test is in the employment industry - that is, the business of
determining whether or not an applicant should become an employee, and whether
or not an employee should stay an employee. American businesses lose billions of
dollars due to employee theft every year (On the night of Wednesday, June 13th,
a red BIC pen disappeared from the office of the Assistant Manager of Marketing.
Where - think back now - where exactly were you that evening?).
Take, first, the question of an
applicant becoming an employee. Often, an employer will hire a polygraph
examiner to give an applicant a psychological once-over. To do this, the
examiner will force the applicant to swear that he has never done drugs, has
never had so much as a strong Irish coffee to drink, has gone to church every
day, often twice a day, since the age of three, etc. The polygraph machine then
spits out a few graphs for the examiner to interpret. In many cases, the
polygraph examiner has the deciding vote in the final decision.
When there has been more employee
theft than is considered normal (a rash of mouse ball disappearances recently
incited the Great Cubicle Riot of Aught-Three), owners have in recent years
begun to turn to polygraph examiners before calling the police. Polygraph
examiners are more likely to find someone guilty because, regardless of their
intentions, the information on which their decision rests is just more
subjective than that of the police. An examiner walks into the building knowing,
knowing that someone is guilty. He is being paid to find that someone
and, like most people being paid good money to do a job, he feels inclined, even
obligated, to succeed.
And now, a Hollywood special: the
only other situation in which polygraph tests are commonly administered is in
criminal cases. For reasons that
remain hazy, New Mexico is the only state in which polygraph test results are
generally admissible. In all other states, both sides need to sign a stipulation
agreeing that the results of the test will be considered admissible regardless
of the outcome.
This is fine, except for the
unfortunate fact that it often results in completely innocent people getting
thoroughly screwed.
How lie
detectors work
The machine itself has five
attachments that must be placed on the subject before the polygraph test begins
(“You survived the fire swamp, so you must be very brave, but no one
withstands the machine”). These are used to gather the data from which
the various graphs are made, and also to ensure that any sense of personal space
or comfort has been well and truly violated.
First, there are two rubber tubes
filled with air, unnecessarily referred to as pneumographs, and they are placed
around the subject’s chest and abdomen. When muscles in said chest or abdomen
expand, the air inside the tubes is displaced, allowing the polygraph machine to
monitor respiratory rate. A blood pressure cuff is placed around the subject’s
upper arm, and is used to measure both blood pressure and heart rate.
Finally, two galvanometers are
placed on two of the subject’s fingertips to measure galvanic skin resistance
(See also: sweat). These rather cleverly measure the skin’s ability to conduct
electricity, which improves with perspiration. Some polygraph machines also
record arm and leg movement, and some examiners use these charts in their
diagnosis.
And now, I am going to spend roughly
thirty minutes painstakingly recreating a real polygraph chart. Mine will be
made entirely of hyphens.
DECEPTIVE CHART
TRUTHFUL CHART
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|-- CONTROL QUESTION --| |--
RELEVANT QUESTION --|
|-- CONTROL QUESTION --| |--
RELEVANT QUESTION --|
Look at the deceptive chart first.
Two types of questions have been asked: a control question (“is your name
Alice?”), and a relevant question (“did you brutally murder several of your
coworkers last week?”). When the subject is lying – that is to say, when
they did in fact murder said coworkers– he responds more strongly to the
relevant question than to the control question. Scientists everywhere are
totally baffled by this behavioral pattern.
On the truthful chart, however, the
subject responds about equally to the relevant question and to the control
question. Now, if you think about it, this is actually a far more disturbing
result – the subject is equally calm discussing his name and discussing the
murders that he is suspected of having committed.
I suppose if his name is really
Alice, though, that’s a bit more understandable.
Now, the effectiveness of the
polygraph test depends almost entirely on the subject’s belief in its
infallibility. The idea runs, basically, that if the subject is innocent he will
believe so strongly in the abilities of the polygraph machine that he won’t
show any signs of nervousness. If the subject is being deceptive, however, he
will be certain that the polygraph machine can 'read' him and will therefore
give himself away through heightened emotional responses. Also, since the
polygraph’s best use is in eliciting confessions, it serves the examiner’s
purpose to have the subject believe that the polygraph machine is completely
accurate.
America has bought into the
polygraph machine wholeheartedly. Europeans, on the other hand, firmly refuse to
have anything to do with them. A room full of educated Europeans and Americans
was once polled, and while 96% of the Americans said that they were willing to
submit to a polygraph test, only 4% of the Europeans agreed.
In the old US of A polygraph tests
are right up there with WeightWatchers, the Red Sox, and apple pie. In fact,
Americans are so convinced that lie detectors can actually detect lying that
some even believe the polygraph test results over their own memories. This is
demonstrated rather spectacularly in the case of Peter Reilly.
Mr. Reilly returned home one day in
1974 to find his mother dying from multiple nasty, stabby wounds on the kitchen
floor. The police showed up, smoked a few cigarettes while poking around the crime
scene, and then had one of their own administer a lie detector test
(police forces often keep a trained polygraph examiner on staff). When they
hooked the unfortunate (and probably mildly hysterical) Mr. Reilly up to the
polygraph machine a few hours later, they discovered that he responded strongly
to the question, “Did you stab your mother repeatedly, and then go off to chuckle about it while she lay dying in the kitchen?” Well,
maybe they
didn’t phrase it quite like that. In any case, Reilly exhibited what the
polygrapher referred to as a ‘strong psychological response,’ which
indicated deceptiveness. Because there’s nothing at all inherently upsetting
about the question, “did you stab your mother?”
The police kept at him, hinting that
sometimes people blacked out and committed extremely violent acts that they
could not later recall. They stressed the total infallibility of the polygraph
test. They asked him if he had ever felt angry with his mother. They pointed out
that no one else was around to have stabbed her. They waved the murder weapon (a
kitchen knife) in his face, and asked him if he had used it to kill his mother.
When he said no, they asked him if he had seen it before. When he said no
again,
they asked him if he had ever seen anything like it... anything vaguely
knife-shaped, or at least metal... prior to the incident. And after twelve hours
of this, Peter Reilly came to the conclusion that he had murdered his mother in
a fit of rage, and then instantly blocked the memory out. He was even willing to
sign confessions, pleading guilty to every accusation and tearfully apologizing
to anyone who would listen.
A few years later, the real killer
was nabbed for something else entirely and confessed to the murder of Peter
Reilly’s mother. Eeeesh.
And a dash of irony
One of the ways that polygraph
examiners instill this brand of total belief is to use what are called ‘stim
tests,’ or stimulation procedure tests. The most common one involves, as do
all good magic tricks, a pack of cards. The polygraph examiner hooks the subject
up to the machine before the actual lie detector test begins. The examiner then
pulls out a pack of cards, and asks the subject to pick one without letting him
see it. Lets say it's the King of Diamonds. The examiner first has the subject
say that he is holding a face card, and then that he is not holding a face card.
After studying the resulting charts for a few moments, the examiner declares
that the former is true. Cue astonishment.
The polygraph examiner then decides
to go a step further, and has the subject say that it is not in the suit of
Spades, not in the suit of Hearts, etc. The examiner states unequivocally that
the card is in the suit of Diamonds. Finally they run through the different face
cards, and the examiner finishes with a flourish, modestly giving all the credit
to the powerful mind-reading machine on the table between them. "The
machine says that the card you are holding is the King of Diamonds. Is that
correct?"
More astonishment, and a growing
feeling of unease on the part of the subject. Even the innocent ones. I actually
had the opportunity to perform this particular stim test on an unsuspecting
classmate of mine when I gave a presentation on polygraph tests. She
described it as both spooky and invasive. Actually, she said that it was "like that
thing could, like, totally read my mind. Like it knew what I was thinking, sorta.
Like it was inside my fucking head. Whoa. I mean, really whoa."
While they aren't always that articulate about it, most subjects
feel something along the same lines. But you
want to know the dirty secret? The really filthy irony of it all? Of course you
do. The truth is that if you looked through the pack of cards that your smiling
polygraph examiner (that is, the one administering the lie detector test)
is holding, you would find no less than fifty-two King of Diamonds cards.
They don't let the subject in on
that little secret, of course.
So, how to polygraph examiners justify
blatantly deceiving just about everyone who walks into their office?
Well, the idea runs basically as follows: for the innocent subjects to respond
equally to control and relevant questions, they have to believe that the
polygraph machine is 100% effective, and never fails. The problem with this
convenient line of reasoning? It isn't, and it does.
Different Breeds of Examiner
Polygraph examiners are, on the
whole, a rather strange and antisocial bunch. I suppose they would have to be,
given their chosen profession. In any case, my attempts to infiltrate their
tightly-knit group were largely unsuccessful (one or two even stood up to the
'admiring youngster' act), so I can only describe one major schism in polygraph
testing theory.
There are really only two main types
of polygraph examiners; clinical examiners, and straight chart examiners (Or 'SCE,'
as the boys around the office have taken to calling them). I'm going to cover
the SCE first. What that means is that the examiner uses only the polygraph
charts to make his decision, and nothing else. The examiner is not supposed to
take into account the active signs of nervousness that the subject was
exhibiting, or those streaks of dried blood on the subject's lapel. The charts
are scored using a standard scale, and the decision is reported exactly
according to the charts. Very numerical. Sometimes, in order to ensure that the
examiner's decision wasn't tainted by his own damned observant nature, the charts are
scored by someone else entirely. Either way, very dangerous. You go first.
The second kind of polygraph
examiner considers himself to be as much a lie detector as the machine on the
table in front of him. He feels that he is a highly-trained agent of Truth -
practically a Honesty Ninja, in fact - and that his observations should
therefore heavily influence the final decision. This type of examiner is, if
anything, even more dangerous than the SCEs. The truly astounding subjectivity
of their decision is partially acknowledged in the fact that what they conclude
is called a 'diagnosis,' rather than a 'result.'
A man named Reid developed the aptly
named Reid Symptom Chart, which was intended to help clinical examiners determine when someone is being deceptive. I believe the take-home
message is
something along the lines of "Smile big, sit still, and eat before you
go."
Deceptive
Truthful
Late for appointment
Eager to take the test
Nervous, resentful, aggressive
Feelings of confidence
Exhibiting mental blocks
Attitude of sincerity/straightforward
Dry mouth/gurgling stomach
Composed/cooperative
Overly friendly/polite
Moving restlessly
Claiming to be religious
Complaining
of pain (from blood pressure cuff)
Eager to leave
Folding hands together
Many similar charts have been created
over the years, and lots of seemingly intelligent people believe in them
wholeheartedly. A well-respected judge in the higher court system, for
example,
recently resigned and decided to let the public in on a little secret. For over
twenty years, he said, he had been able to determine without question who was
guilty and who was innocent. As a judge, he could then treat them accordingly.
You can tell, he told the eager listeners, because a guilty person will always
touch their nose during the trial.
No bullshit.
Types of Polygraph Tests
Relevant/Irrelevant (R/I) Test
The first type of polygraph test was developed in the 1920's, and it is
still commonly used today. It is called the
Relevent/Irrelevent test, or R/I test. For this exam, there are two types of
questions: relevant questions ("Did you kill her?"), and Irrelevant
questions ("Is today Tuesday?"). Three relevent questions are asked,
and each one is preceded and followed by an irrelevant question. A subject is
considered to be deceptive if their reaction to the relevant questions is much
stronger than their reaction to the irrelevant questions. Now, the problem with
this should be immediately obvious. Some questions are just more inherently
upsetting than others, and just as much so for the wrongfully accused as for the
murderers.
Because of this, the chance of an
innocent person being classified as deceptive is actually greater than if
the judge had just flipped a coin. Downright spooky, if you ask me.
Fortunately,
those few polygraph examiners who acknowledge this flaw have been working round
the clock from the 1920's on to develop more accurate methods.
Lie Control Test (LCT)
The LCT is like the R/I test, except
that what are called 'control' questions are used. Before the test, the examiner
explains that the control questions are used to 'get to know' the subject. For
example, the polygraph examiner might ask if the subject has ever cheated on
income taxes. If the subject says no, it is assumed that he is lying. The
emotional response to this 'known' lie (on the polygraph charts) can then be compared to their reaction to the
relevant questions. If the reaction to the
relevant question is much larger than the reaction to the control, the subject
is clearly lying.
The problem with this, succinctly, is
that not all lies are psychologically equal. Denying something that is commonly
done, such as cheating on income taxes, is not the psychological equivalent of
denying that you killed someone. Other control questions include "have you
ever stolen money from a company while employed there," and "have you
ever done drugs?"
There is a second problem with the
concept of control questions, of course. What if Jane Smith really hasn't ever
cheated on her income taxes? She says 'no' the way she was instructed to, and
does so with the warm, proud glow of excessive honesty in her heart.
Too bad that she's
thrown in prison for murder a few months later. Maybe her attorney will come and
visit once in a while.
Truth Control Test (TCT)
Next, the few polygraph examiners left
who still maintained a modicum of rationality decided to try the same theory,
but in reverse. They developed what is known as a 'guilt complex comparison
question,' and then failed spectacularly to put it to the test. For this type of
test, the examiner invents an entirely fictitious crime of a similar type and
magnitude to the subject's original crime. They pretend to be examining the
subject about both. Say, for example, that a nice digital camera went missing
from the CEO's office. The bold little punk who may or may not have done it is
dragged in front of a polygraph machine, and told that the CEO's nice wrist
watch also went missing a few weeks back. The boss didn't report it at the time,
they tell him, but now he's looking for the culprit.
Because the subject is known to be
telling the truth when they deny involvement in the second crime (remember, it's
fictitious), their emotional response to those accusations and the real
accusations can be compared. If the subject reacted quite a bit more to the real
crime than to the invented crime, they are classified as being deceptive. The
good thing about this method is that it allows the examiner to set a
baseline;
if the subject is that emotionally upset to begin with, a certain amount must be
factored out of her final polygraph charts in order to make the readings
accurate.
This sounds quite a bit more
promising, but there are two problems with it. The first is that the subject has
to actually believe - completely, 100% bought in - that they are in just as much
danger from the fictitious crime as from the real one. If they are innocent
their emotional response to the control question, which they had to have
answered honestly, should be the same as their emotional response to the
relevant question. Unfortunately, this kind of belief in a secondary crime can
be difficult to instill in someone - I mean, how many watches does the boss
really have? Seems kinda fishy, if you ask me. If the person has even some doubt
as to the validity of the second accusation, then their emotional responses to
questions regarding that crime will be significantly smaller. So they seem
guilty, when really all they are is a good, home-grown, modern day
skeptic.
The second problem with this type of
lie detector test is that it requires deceiving the subject, which is supposed
to be some kind of moral issue, or something. Fortunately, most polygraph
examiners don't let that bother them.
Positive Control Test (PCT)
Subjects taking the PCT are asked only
relevant questions, and they are instructed to answer each one twice; the first
time, they are supposed to answer 'yes,' and the second time, they are supposed
to answer 'no.' Since the question is the same, theoretically the only factor
that could account for different reactions is that one answer is known to be
deceptive. So, if the subject responds more strongly when they say that they did
not commit the murder, it would imply that they did, in fact, commit it.
Do you see the problem?
As with some of the previous, the
problem falls squarely in the interpretation. Different factors could be
responsible - maybe the person reacts more strongly to the 'did not' reply
because they're worried that the authorities don't believe them. Alternatively,
this might get a real killer pronounced innocent, when he is more upset by the
admission of true guilt. Also, again, some sentences are just more disturbing to
say or think than others. Admitting to rape, for instance, would cause a rather
large emotional response in a rape victim.
Echhh. Gets pretty muddy, don't it?
Relevant Control Test (RCT)
This is more of a general test, used
when there's no single crime being discussed - for example, during job
application screening. The subject is asked vague relevant and irrelevant
questions such as "is your last name Tong," followed by "have you
ever used drugs before coming to work?" Theoretically (and I have a homework
assignment for you - go back and count the number of times the word
'theoretically' appears in the writeup), since there's no specific crime, a
reaction to any one of the relevant questions should indicate deceptiveness in
that area.
What we have here, kids, is another
relatively useless style of polygraph exam. Suppose, just for a fun
experiment,
that a friend of yours recently died of a drug overdose. You yourself had never
used drugs (we-ell... not since Harvard, anyway), and you had been trying to get
him help for months now. You apply for a new job, and they begin asking you all
kinds of questions about drugs, drug use, etc. Pop Quiz: are you exhibiting a
strong emotional reaction to the questions?
(A) No, because I never liked that guy
anyway.
(B) Yes, but I'm responding even more strongly to the questions about child
molestation because of the... 'incidents'
(C) Yes.
There are a thousand other reasons for
someone to respond more strongly to one type of question than to another, and
most of them don't indicate any deceptiveness on the part of the subject.
Searching Peak of Tension (SPOT)
Test / Guilty Knowledge Test
Instead of detecting lying, this type
of lie detector test detects guilty knowledge. As you might have guessed from
the absence of the word ‘theoretically’ in that last sentence, this is by
far the most promising technique developed so far. What this type of test does
is look for a ‘peak of tension,’ or point where the emotional reaction is
the highest by a considerable amount, rather than just comparing responses.
This is best used, for example, in a
kidnapping case. Say that seven suspects are brought in. Each is shown a series
of photographs of children of about the right age, one of which is the kidnapped
child. Now, only the kidnapper would know which child had actually been
kidnapped, and so seeing that photograph in particular would (and here,
unfortunately, I must use the t-word) theoretically trigger a stronger emotional
reaction.
The other good thing about this type
of test is that it provides a baseline; if one of the suspects is reacting very
strongly to all the photographs, it can be assumed that he is just generally
upset, and not necessarily guilty.
The other time that this test is
useful is even more morbid: crime scenes. The cops are instructed to take
pictures of the scene with the dead body dragged to different locations, and
these pictures are then shown to the suspects. Though all are gruesome, only the
real murderer should know which one shows where the victim actually died.
Now… the problems. The first problem
is that the media tends to get involved, splashing pictures of the kidnapped kid
all over the newspapers in the admittedly reasonable hope that he will turn up. Once pictures of the
child are widely available, however, the police can no longer use the SPOT test
to determine who is the kidnapper.
The second problem is, simply,
psychopaths. It seems fairly intuitive that the kind of person capable of
committing a grisly murder is likely to be the kind of person who isn’t overly
affected by it. Not always, certainly, but it does make the test slightly
pointless.
Black Sheep Syndrome (BSS)
Voice Stress Analysis is sort of the
uncle that nobody talks to of lie detector tests. The uncle that's always
getting drunk at three in the afternoon, and then shouting bad jokes that he
forgets the endings to while simultaneously trying to flirt with one of his
niece's friends.
Err... that is, voice stress analysis
is what the polygraph examiners keep around to make them feel better about their
own jobs. Voice Stress Analysis operates on the basic and largely flawed
principle that emotional arousal can be detected through vibrations in the throat
and larynx muscles. It’s measuring stress instead of lying, and not
even doing that terribly well.
This technique was, of course,
developed in the 1960’s. It was immediately used on old clippings from the Lee Harvey Oswald trial (the person doing the testing came to the conclusion that Oswald was innocent, which I think tells you all you need to know about voice stress analysis).
In a masochistic sort of reverse case
study, one supporter of voice stress analysis asked a group of people to look at
a number of slides, half of them pastoral landscapes and half of them mutilated
corpses. The subjects were then asked to say “yes, I like this picture” in
response to each. Three judges studied the results independently, and tried to
guess in each case which type of picture the subject was observing. Sorting at
random, let me remind you, would have produced 50% correct guesses for each
judge.
Judges One, Two, And Three were
correct about, respectively, 50%, 40%, and 35% of the pictures. From this, we
must conclude one of two things; voice stress analysis is worse than
useless, or
there are an awful lot of sick people wandering around out there.
The Second Half of this Node (Oh,
God! Will it never end?)
The real problem with lie detectors
(and forgive me if you have already drawn this conclusion yourself) is that they
don’t work. Polygraph examiners claim accuracy ranging from 95% to 99%, but
there are three problems with this.
(1) Polygraph examiners want the
machines to work, and so they will creatively interpret the data. Not lie,
precisely, but… well, I like ‘creatively interpret.’ They are more likely
to remember the good (times when they were right) than the bad. This is of
course perfectly normal (because who wants to acknowledge the fact that their
chosen profession is complete bunk?), but it does lead to a certain
bias.
(2) Polygraph tests are extremely intimidating (at least, if you’re American
they are), and so they tend to elicit confessions. A polygraph examiner
considers a confession to be a correct diagnosis, even if the charts said
differently. Some polygraphers never ever bother to score the charts and
determine what they would have decided on their own.
(3) Finally, for the vast majority of their cases, polygraph examiners never
know whether they were right or wrong. If a subject who was diagnosed as
‘deceptive’ goes to jail (even if it’s on the strength of the diagnosis),
then the examiner can feel free to chalk it up as another brilliant success in
the name of Science.
As in the case of
Peter Reilly, however, many Americans believe so strongly in the results that
they can convince themselves that their own memory is flawed, rather than
acknowledge that the machine might be. Polygraph machines actually have a validity that varies between 70%, for the good ones, and closer to 50%, for the
bad ones. That’s only a little better than a coin toss. Since polygraph
machines offer a solid answer (a guilty/innocent verdict) rather than
testimony,
they need an accuracy far better than 70%.
How to Approach
Taking the Polygraph Test
Did you note the
careful wording? Is it too late in the node to take up political correctness as
a hobby?
Probably.
How to Beat a
Polygraph Test
There, that’s
better.
Now, chances are
fairly good that you will, at some point, be asked to take a polygraph test. If
not for murder, then probably for a job application.
The first step in
beating a polygraph test is to completely refuse to take one. The test is
never obligatory, and in many cases it can be turned down flat. Sometimes, however,
social pressure rears its ugly head. Refusing to submit to a polygraph exam can
be interpreted as an admission of guilt, and for that reason it can’t always
be avoided.
There are two types
of countermeasures to take if you are forced to take a polygraph test.
Behavioral
Manipulation
First of all, make
no admissions, except if you’re asked if you’ve ever committed some extremely
minor crime such as lying to your parents in high school (‘extremely
minor’, right, dad?), or accidentally stealing pens from work. In any case,
sign absolutely no statements. Even if it’s something you admitted to during
the pre-test interview or as part of a control question – anything you sign
can quite easily be used against you later in a variety of vicious and diabolic
ways.
Remember not to trust your polygraph examiner. It isn’t an
interview, it’s an interrogation,
and you should be able to recognize the common interrogation techniques. The
most common is a projection of a false sense of empathy, trying to make you
believe that your polygraph examiner is your friend, and is there to help you.
He isn’t. Don’t believe his lies. Paranoid? Why, no. What on earth would
make you think that?
Other examiners will
take an aggressive approach and try to appear threatening. These two techniques
are sometimes combined, for extra fun and excitement. Think ‘good cop, bad
cop.’
Finally, a
particularly cruel brand of job applicant screening examiners will use an egotistical approach, during which they
play up your accomplishments and good
points. This is designed to make you feel that you aren’t just some ordinary
applicant, and that the company will go to any lengths to hire you.
Other ways you can
help your case is to make a good first impression by arriving on time, dressing
professionally, and keeping eye contact.
Remember – you are
being watched. In the waiting room, during the pre-test interview, and during
the testing. Some polygraph machines even have extra sensors that detect
motion.
During the pre-test interview it is important to be friendly and polite, to
admit to nothing more than some minor childhood misdeeds, and to keep your
answers fairly short. Avoid, for example, saying “yes, basically” when you can just say
“yes.”
Why do I feel like
I’m leading some kind of morally ambiguous “Learn to Lie in 10 Easy Steps”
type seminar?
No matter. Now,
polygraph examiners love mind games. Some of the most common ones are
below:
(1) Upon entering
the room, you may find your chair facing the wrong direction. By making you move
it, the examiner is (subtly?) indicating that he is in control of the
situation.
(2) Here’s an especially diabolical one. You are instructed to go into the next
room and wash your hands. According to the examiner, this is so that the
machine can get a better reading. A filthy lie. You are then observed (told
you). If you fail to wash your hands, it is interpreted as a desire to fool the
machine, which is a strong indicator of deceptiveness.
(3) And then, for the slightly dimmer bulbs out there, polygraph examiners have
developed another commonly used mind game. You are left alone in the room on
some pretext. As the examiner is leaving, he instructs you not to touch the
machine, because even the slightest change will completely invalidate the
results. You’re then watched, to see if you will try and loosen any wires,
etc. Of course, you won’t try. You’re much too bright for that. But it’s
terrifying how many people do.
One other behavioral
manipulation. Most polygraph examiners will ask you at some point how much you
know about polygraph testing. Don’t admit to knowing much, because that will
immediately make the examiner suspicious. Instead, say something like “I heard
on TV that they’re pretty much always right.” Improvise.
Chart-recording
Manipulation
First off, there are
some breathing countermeasures that will help steady your respiratory rate during the exam.
Practice maintaining a baseline breathing rate of 15-30 shallow
breaths per minute. Keep this up from the moment the pneumograph tube is placed
around your chest. Remember not to change the pattern once the last question has
been asked – an especially sneaky examiner may continue recording for several
minutes.
When you recognize a
control question (“Is you name…?”), change your breathing pattern to one
of the ones below:
-Hold your breath
for 4-5 seconds after breathing out.
-Breathe more slowly for the next 5-15 seconds, ending before the next question
is asked.
-Take several shallower breaths for 5-15 seconds, ending before the next
question is asked.
-Allow your breathing to get gradually shallower for 5-15 seconds, then return
immediately to your baseline.
That takes care of
breathing, but you have more than just the pneumograph strapped to you during
the exam. The second type of chart-recording manipulation are Cardio/Electrodermal
countermeasures. Use only one of the following:
(1) Mental
countermeasures, such as doing mathematical calculations in your head as quickly
as you can. Pick an arbitrary number and count backwards by sevens.
Alternatively, think about something upsetting, like falling off a cliff.
(2) Physical countermeasures, such as biting down on the side of your
tongue. Do
this as soon as you recognize a control question or just after answering it, and
continue biting for no longer than 20 seconds, pausing to answer the question. A
potentially harmful alternative is placing a tack in your sock, and pressing
your toe against it at the right moment.
Finally, during the
stim test, make sure to augment your responses so that when you respond strongly
to control questions (respond, in fact, as though you had just stepped on
something sharp), the examiner will assume that the heightened response is
normal.
And... well, that's about it.
FIN
Sources
(only the best for Everything2):
<http://www.antipolygraph.org> (if you have to take a polygraph test, I recommend downloading their free book on how to... ahem... approach the lie detector exam).
Lykken, David T. A Tremor in the Blood: Uses and Abuses of the Lie Detector.
1998.