The recorded differences and purported indicia of deception
may be caused
by numerous variables. These unassessable factors are crucial to
an accurate
polygraph examination. Among the proven variables are: (1)
physical
characteristics of the subject such as fatigue, obesity, heart
disease,
respiratory difficulties and abnormal blood pressure; (2) temporary
or permanent
mental disorders such as delusions, feeble-mindedness or insanity,
which result
in an inability to affirmatively participate or to be unable to
differentiate
between right and wrong; (3) the undetected use of alcohol or
drugs; (4)
distractions in the examination setting, such as extraneous noises,
temperature
fluctuations, or unusual objects; (5) the responses to his/her own
lying; (7) a
guilty party's subjective belief in his/her own innocence; (8)
excessive previous
interrogation; (9) prior dry run examinations leading to belief
that one can beat
the machine; (1) the complexity of the matters being investigated;
(11) the
wording of the relevant questions; (12) the extent of motivation
and fear by the
subject that the polygraph will detect his/her lying; and even (13)
the
nervousness of an innocent subject induced by fear or a guilty
complex involving
a different offense.