I, EDWARD S. KATKIN, being first duly sworn, state under oath the following:

    1. I am a Professor of Psychology at the State University of New York (SUNY) at Stony Brook, New York. I served as Dean of the Division of Social and Behavioral Sciences at SUNY-Stony Brook from 1993-1996. My curriculum vitae is attached hereto as Exhibit 1.
    2. One of the fields in which I have conducted extensive scientific research is psychophysiology. I have been the author or co-author of more than 100 scientific articles and papers in the field of psychophysiology. During 1983-84, I was President of the Society for Psychophysiological Research, which is an international scientific society devoted to the advancement of basic and applied scientific knowledge in that field. I served as Chairman of the Polygraph Validity Advisory Panel, which was a scientific advisory panel, for a study of polygraph tests conducted by the Office of Technology Assessment in 1983. See Scientific Validity of Polygraph Testing: A Research Review and Evaluation - A Technical Memorandum (Washington, D.C.: U.S. Congress, Office of Technology Assessment, )OTA-TM-H-15, November 1983). From 1992-1996, I served as a member of the Curriculum and Research Advisory Committee of the Department of Defense Polygraph Institute. Another field in which my work is concentrated is clinical psychology. I am a licensed psychologist in the State of New York, and in my capacity as a Professor of Psychology at SUNY-Stony Brook, I train persons in the field of clinical psychology.
    3. I have not conducted applied research concerning polygraph examinations, nor do I conduct polygraph examinations. However, as a scientist actively working in the field of psychophysiology, I have been for many years a close and knowledgeable observer of the development of basic psychophysiological science as well as certain areas of knowledge in applied psychophysiology, including the polygraph examination. I have served as a peer reviewer of manuscripts of scientific monographs concerning the polygraph submitted for publication to the journal, Psychophysiology. I have attended scientific meetings and symposia concerning polygraph examinations. In sum, although I have not been a direct participant in scientific research concerning the polygraph, I believe my scientific training and experience qualify me to evaluate objectively the state of scientific knowledge concerning the polygraph, and the extent to which scientists who are knowledgeable about scientific research concerning the polygraph accept it as scientifically reliable and valid.
    4. It is my opinion, based on extensive review of the scientific literature concerning the polygraph that:
    5. a. The reliability of the results of certain types of polygraph examinations of suspects in criminal cases has been tested in a substantial number of field studies. These studies have evaluated the reliability of the control question technique and a variant of that technique known as the directed lie test. The scientific value of these field studies has been subjected to peer review with respect to their scientific methodology, and subsequently published in some journals that are properly respected by scientists.

      b. The reliability of certain types of polygraph examinations, including the control question technique and the directed lie test, has also been evaluated through numerous laboratory studies. The scientific value of these laboratory studies has been subjected to peer review with respect to their scientific methodology and value, and subsequently published in some scientific journals which are properly respected by scientists.

      c. When the totality of the scientific studies are considered together, including the most recent studies, the data show that confidence in the accuracy of the results of a polygraph examination is acceptably high by usual psychological standards if the test is administered by a properly qualified and trained polygraph examiner using the controlled question technique or the directed lie technique.

      d. Much of the controversy among scientists who are knowledgeable about the validity of polygraph examination results is focused on the rate of false positive results, that is, to subjects whose test results erroneously indicate that they have given deceptive responses to the relevant questions. This concern is especially related to the use of polygraph tests for employment screening, in which the base rate of undesirable candidates is quite low. It can be shown mathematically that when the base rate of "guilt" is very low, then as many as 50% of subjects identified as guilty are in fact innocent. The same mathematical analysis indicates that in such conditions (i.e., low base rates of guilt), the percentage of subjects who are identified as innocent, but are actually guilty (false negatives) is between 1% and 2%. There is considerably less controversy among scientists about the validity of the polygraph test when it is used in evaluating deceptiveness about specific incidents that took place prior to the examination. My own assessment of polygraph studies leads me to have somewhat greater confidence in the accuracy of a properly administered polygraph test which indicates that the subject did not give deceptive responses to relevant questions than in results of a similar tests which indicate that the subject did give deceptive responses to the relevant questions. The scientific data concerning the reliability of polygraph tests indicates that when proper procedures are employed, and a well trained examiner administers the test, false positive results are somewhat more likely to occur than false negative results. My review of the scientific literature indicates that the rate of false negative errors, that is, the rate at which deceptive subjects erroneously pass the test, is low (about 10%).

      e. The occurrence of a low rate of false negative errors on properly conducted polygraph tests of criminal suspects is accepted by a substantial portion of the informed scientific community as having been established empirically through scientifically conducted investigations and, for that reason, is not contested nor controverted by a substantial majority of scientists who are knowledgeable about scientific research concerning polygraph tests of suspects in criminal cases.

    6. As a scientist and practitioner in the field of clinical psychology, I am aware of the widespread forensic use of various types of psychological and psychiatric examinations, including the use of standardized diagnostic tests, in order to determine whether persons involved in criminal cases suffer from a mental disease or defect, r are predisposed to be repeat offenders. These tests also purport to identify persons who are malingering or attempting to deceive the examiner with respect to their mental health. I am also aware that there are data, generated by field or laboratory studies employing scientific testing methodology, demonstrating the reliability and scientific validity of the results of such diagnostic examinations. It is my opinion that the body of empirical data supporting the reliability of polygraph test results is as valid and trustworthy as the body of scientific data commonly relied upon as the basis for the forensic use of diagnostic examinations to detect psychological defects.
    7. As previously noted, I am not and have not been involved directly in conducting scientific research concerning polygraph examinations. However, I believe that I am a scientifically knowledgeable and objective evaluator of the psychophysiological theories which have been advanced as the underlying explanation for the reliability and scientific validity of polygraph examinations. In science, it is frequently true that we initially observe certain empirically verified relationships without a completely detailed theoretical understanding of how and why these relationships occur or operate. In such circumstances, science advances theories that attempt to explain these phenomena. At this time we do not have a complete or compelling theory to encompass all of the findings from laboratory and field investigations of polygraphy, but the empirical findings are sufficiently strong to demand further theoretical development. There is general consensus, however, on some theoretical elements. No serious polygrapher accepts the proposition that there is a specific pattern of physiological responses that is isomorphic with lying. Rather it is almost universally accepted that when a person experiences distress there are automatic reflex reactions that may be indexed by subtle changes in activity of the sympathetic division of the autonomic nervous system, and that among the most reliable indexes are changes in palmar sweat gland activity and cardiovascular reactions. The task of the polygrapher is to interpret the pattern of stress response that are elicited from a subject to relevant questions and control questions. Inferences about guilt or innocence are then drawn from the pattern of responses to these two kinds of questions. In the directed lie examination, the subject is being deceptive to both the relevant and control questions, so inferences about guilt or innocence are drawn on the basis of which specific act of lying elicits greater signs of the autonomic nervous systemsís "emergency." In the field of psychophysiology, the fully detailed and verified explanation of these psychophysiological process may be enhanced significantly by further advances in brain imaging and studies of electrical activity of the brain. For the present, it is my opinion that the protocol which is followed when a properly trained and experienced polygraph examiner administers the directed lie polygraph examination to a suspect in criminal case is likely to yield results that can be useful in helping to make a determination of which et of questions has elicited a greater distress reaction. Absent alternative explanations, it is logically reasonable to attribute the greater stress reaction to either set of questions (i.e., the relevant or the control) as an index of the personís reaction to being deceptive about those questions.

Signed under the pains and penalties of perjury this day of July, 1997.


Edward Katkin




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