Many people are nervous about taking a polygraph, and they may try to research
the testing procedures on the internet. Sometimes they feel that they
can “beat” the equipment by the use of popularly known deception
- One popular suggestion is to use antiperspirant on your fingers and palms.
This is thought to impede the polygraph’s ability to gauge your
sweat gland’s reactions. What actually may happen is that if the
antiperspirant works it will prevent the machine from making any readings
at all for that measurement. This is a tell-tale sign of deception. You
will be told to wash your hands to clean off the antiperspirant, and the
examiner will mark your test as attempted deceptive.
- Lie on the control questions – Some of the questions asked on a polygraph
are only there to set a baseline for your tests. A control question might
be something like “is there anything you hope I don’t ask
you?” or “have you ever done anything you felt guilty about?”
The advice goes if you lie on those questions, then the test won’t
have a bona-fide basis for comparison. What actually happens is that the
examiner will know that you are lying on the control question (for example
everyone at some point in their life has felt guilty or lied about something).
The examiner will simply select another control question to be used as
a basis of comparison, and will know you are attempting to be deceptive.
- Changing your breathing patterns – Some internet authorities suggest
that you can beat a polygraph by carefully holding your breath at critical
intervals during the polygraph test or biting your own tongue. The problem
is that most experienced polygraph administrators have been trained to
look for these standard countermeasures and will know that you are attempting
to be deceptive. Another problem is that unless you have access to a polygraph
machine to practice on, and know exactly what the examiners are looking
for in scoring your test, you will not be able to effectively control
your breathing in such a way as to manipulate the outcome.
People who are considering trying to beat a polygraph may also mistakenly
assume they only have to fool a machine. In reality you would have to
fool a trained, licensed professional examiner who may have decades of
experience in administering thousands or tens of thousands of test.
The best advice that we can provide to those who are considering whether
to subject themselves to a polygraph can be easily summed up as follows:
- If you are the subject of a police investigation do not take a polygraph
until you have retained a lawyer, passed a private polygraph and your
lawyer recommends that you take the police test;
- This advice does not change even if you believe that you are being wrongly
or unfairly accused of a crime. Polygraph tests are very accurate, but
on rare occasions there are false-positive test results. No one should
discover that they are not a good candidate for this test at the police
station (when it is too late).
I frequently make use of polygraph examinations when I have a client that
I think could benefit. I do this both for cases in the pre-arrest and
post-arrest stages. I reason that there is no downside to a client who
maintains that they are innocent of the charges to take a polygraph in
my office. If they pass the results can be shared with the police or the
prosecutor, and if they don’t pass then no one knows the test was
even taken at all. Favorable results have helped my clients avoid serious
charges such as child molestation, burglary, or murder.