Reply to Anonymous SMS Inquiries

[George W. Maschke]

Dear Anonymous,

You write:

Please post comment on your web site to question: Is there a text book, accepted by those who favor or support polygraph use, which states that a GSR response alone, without any indications from breathing, blood pressure, or heart rate, can not be used in isolation to justify a "deceptive result", but rather could only justify either an "indeterminate/undetermined result", or a "no deception indicated result"? I need one of their own books which I can cite in court.

I am not aware of any polygraph textbook or instructional material that explicitly propounds such. Typically, however, numerical scorings of the electrodermal channel are combined with scorings of the respiratory and cardiovascular channels to reach a combined score.

The most relevant materials to which I could refer you are the Federal Psychophysiological Detection of Deception Examiner Handbook:

https://antipolygraph.org/documents/federal-polygraph-handbook-02-10-2006.pdf

and the DoDPI (now NCCA) Numerical Evaluation Scoring System:

https://antipolygraph.org/documents/federal-polygraph-handbook-02-10-2006.pdf

For the purpose of rebutting polygraph "evidence" in court, however, I think that instead of arguing that the polygraph chartgazer misread his scrolls, it would be better to attack the notion that polygraphy has any evidentiary value whatsoever. It is thoroughly discredited pseudoscience. You might cite, for example, Professor William G. Iacono's article, "Forensic 'Lie Detection': Procedures Without Scientific Basis":

https://antipolygraph.org/articles/article-018.shtml

Chapter 1 of The Lie Behind the Lie Detector also gives a good overview of the scientific evidence on polygraphy with citations to primary sources:

https://antipolygraph.org/lie-behind-the-lie-detector.pdf

You also write:

Please post answer to QUESTION: has there ever been an actual "double blind study", published in a peer reviewed scientific journal, which is also recognized by another independent peer reviewed scientific journal? Or any "double blind study" whatsoever? Even knowing of the complete list of such studies, authors, where details might be found and subsequently criticized can be very helpful.

I am not aware of any arrangement whereby peer-reviewed scientific journals "recognize" studies published by other such journals.

There are peer-reviewed laboratories studies where polygraphers were blind with regard to the truthfulness or deceptiveness of examinees (indeed, that's typical); however, they may not have been blind with regard to other significant variables, in particular, the base rate of deceptive examinees in the subject population. And polygraph operators typically are not blind to the fact that they are participating in a study.

A non-peer reviewed racial bias study that DoDPI, evidently not liking the results, suppressed and never published, did evaluate polygraph outcomes of examiner trainees who were unaware that their conclusions were being used for such a study. It showed innocent blacks failed at a rate significantly higher than innocent whites, and that innocent subjects of both races failed at high levels. In aggregate, less than 60% of tests resulted in a correct decision having been rendered:

https://antipolygraph.org/documents/dodpi-racial-bias-study.pdf

The best list of polygraph studies I could refer you to is that included in the 2002 National Research Council report, The Polygraph and Lie Detection:

http://www.nap.edu/openbook.php?record_id=10420&page=232