Is It Time to
Reject the Friendly Polygraph Examiner Hypothesis (FPEH)?
Charles R. Honts
Boise State University
Paper presented at the meetings of the
American Psychological Society
24 May 97, Washington, D.C.
The Friendly Polygraph
Examiner Hypothesis (FPEH) is a notion that was first described
by Orne (1975). The FPEH suggests that polygraph examinations
conducted for the defense on a privileged and confidential basis
are more likely to produce false negative outcomes than when subjects
know that the examiner will report adverse outcomes. The FPEH
assumes that if the subject expects that only a favorable outcome
will be reported, the subject will have little at stake and will
have no fear of the detection of deception. This lack of fear
of the detection of deception will reduce the threat posed by
the crime-relevant questions in the polygraph examination and
the guilty subject will be more likely to pass.
Since Daubert v.
Merrill Dow Pharmaceuticals, Inc. (1993), the issue of the
admissibility of polygraph has again become an open issue in U.
S. courts of law (McCall, 1996). The FPEH is one of the main objections
raised by prosecutors (Raskin, 1986), scientific critics of polygraph
testing (e. g., Iacono & Lykken, in press) and by some law
enforcement agencies (Murphy, 1996) to the admission of defense
offered polygraph tests. Legal rulings in the U.S. are currently
mixed with regard to the validity of the FPEH, with some courts
finding it to be without validity (e. g., U. S. v. DeLorean,
1984; U. S. v. Galbreth, 1996) and other courts finding
it compelling (U. S. v. Caillier, 1996). The present effort
analyzes the FPEH by three methods: a logical analysis of the
assumptions and conclusions of the FPEH, a review of the published
scientific literature, and finally through new data from confidential
and non-confidential field cases.
The Comparison Question Test
Most polygraph tests
conducted for forensic purposes use some variant of the comparison
(control) question technique (CQT). There are two active elements
in a CQT: Relevant Questions which deal directly with the matter
under investigation (e.g., Did you shoot John Doe?) and Comparison
Questions to which the subject is either directed or maneuvered
into lying (e.g., Before 1996, did you ever do anything that was
dishonest or illegal?). The rationale of the CQT requires differential
responding between these two active elements. Guilty subjects
are expected to respond more to relevant than to comparison questions
while innocent subjects are expected to respond more to comparison
than to relevant questions. Equivalent response to both the relevant
and comparison questions results in an inconclusive outcome.
Two basic assumptions
underpin the FPEH: (1) Fear of the detection of deception is necessary
for the CQT to function. (2) There is no fear of detection of
deception (or other motivation) in a confidential polygraph examination.
First, there is no basis
for assuming that fear of the detection of deception is necessary
for the CQT to function. Physiological detection of deception
has been demonstrated in numerous laboratory studies under no
motivation, reward motivation, punishment and even when the subjects
did not know they were in a detection of deception situation (see
the review by Steller, 1986). No differences between these motivational
conditions has been reliably observed. Although fear may be sufficient
for the detection of deception it clearly is not necessary. Fear
is not an important part of any modern theory of CQTs.
Even if fear were necessary
for detection, it does not follow that a reduction in fear would
allow a deceptive person to pass the test. The CQT requires differential
reactivity between relevant and control questions. A reduction
in fear would reduce the fear associated with both question types
thus maintaining the differential reactivity between the two.
Since these tests are evaluated within-subjects, and not against
a normative standard, the effect of reducing the motivation level
(fear) would be nil.
Finally the FPEH's assumption
that there is no fear (or any motivation) in a confidential polygraph
is unrealistic. The subject of a confidential polygraph in criminal
case has a clear motivation, the gain she or he will receive from
passing the test. Clearly this is a more powerful motivation than
the small monetary rewards used in most laboratory studies.
Validity in the Laboratory
If the FPEH were correct,
then one would expect that laboratory studies of the CQT, run
under conditions that do not include negative sanctions associated
with deceptive outcomes, to produce a large number of false negative
errors. This is clearly not the case. The present analysis reviewed
16 laboratory studies of the CQT (see Table 1). None of which
contained negative consequences for failing the examination. Those
studies included 457 guilty subjects and 361 innocent subjects.
Over all of the studies, the false negative rate was 11.00% while
the false positive rate was 16.63%. This outcome is the opposite
of the prediction generated by the FPEH. Notably, five of the
16 studies reported no errors with guilty subjects, despite a
lack of fear or any negative sanctions associated with failing
Table 1. Outcomes of Laboratory Studies of Comparison
|Barland & Raskin (1975)||36
|Barland & Honts (1990)||20
|Honts & Barland (1990)||44
|Honts et al. (1985) Exp. 1||12
|Honts et al. (1985)1 Exp. 2
|Honts et al. (1987)1 ||10
|Honts et al. (1994)1||20
|Horowitz et al. (1997) 2||15
|Kircher & Raskin (1988)||50
|Otoole et al., (1994)||64
|Podlesny & Raskin (1978)||20
|Podlesny & Truslow (1993)||72
|Raskin & Hare (1978)||24
|Rovner et al. (1979)1||24
|Szucko & Kleinmuntz (1981)||15
Control Question subjects only.
Data From Actual Cases
An exhaustive sample
of field case data from an experienced polygraph examiner who
conducted both confidential and non-confidential polygraph examinations
was examined. Between January of 1983 and April of 1997 this examiner
conducted 110 confidential and 40 non-confidential polygraph examinations
that resulted in a decision. If the FPEH were correct, then the
percentage of subjects passing the polygraph should be much higher
in the confidential than in the non-confidential tests. This was
not the case, 56.30% of the confidential tests were passed, while
70.00% of the non-confidential tests were passed. This is not
different than chance c2
(1) = 0.15, ns, but the trend in the data is in the opposite
direction of that predicted by the FPEH.
- The FPEH does not
make sense in the context within which confidential comparison
question tests are actually conducted.
- Predictions of the
FPEH find no support in laboratory data where the effects should
be the strongest.
- Predictions of the
FPEH find no support in field data of confidential and non-confidential
comparison question tests.
The Friendly Polygraph
Examiner Hypothesis is completely without logical or empirical
support and should be abandoned as a reason for opposing the use
of defense offered of polygraph examination in courts of law.
Posted Online on 1 June 1997
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