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Examination And Cross-Examination Of Experts In Forensic Psychophysiology Using The Polygraph

by James A. Matte, Ph.D.

By James A. Matte, Ph.D.   Email:


This book is designed to prepare the attorney at law who wishes to lay the foundation for the admissibility of the results of a psychophysiological veracity (PV) examination using the polygraph as evidence in a court of law. It is also written for the various experts whom the attorney will depose in the process, such as physiologists, psychologists, psychophysiologists and forensic psychophysiologists who will also benefit from the model scripts of testimony by those experts set forth in this book.

While the scripts, which comprise questions posed by the attorney and ideal answers from the expert witnesses, will provide much detail about the psychological structure of the more advanced PV examinations and the physiology recorded and analyzed, these scripts are not intended to cover the vast amount of information on the subject contained in Forensic Psychophysiology Using the Polygraph (Matte 1996) [Fn 1], an 800-page textbook, which provides in-depth information that can be useful in the examination and cross-examination of those experts. The attorney should heed the welcoming remarks of Dr. William J. Yankee, Director of the Department of Defense Polygraph Institute (DoDPI) at the 1990 Federal Interagency Polygraph Seminar at the FBI Academny, who stated that "We must realize that a polygraph examination is one of the most complex psychophysiological examinations ever developed." A review of the literature (Matte 1996; Chapters 11, 15, 17, & 19) regarding forensic psychophysiology reveals that there are several different PV examination techniques available to the forensic psychophysiologist, who may employ them in a variety of cases according to the legal objectives which meet the scientific requirements of the selected technique. The major differences in these PV examination techniques are discussed in Chapter 3 of this book.

There are numerous areas where the defense attorney can use PV examination results. Whenever there is a factual dispute regarding a distinctive issue, the PV examination may be used to prove or disprove essential elements of his/her client's verion of the incident or matter. This includes civil as well as criminal cases. The following are some of the areas where the PV examination is frequently used. Not all instances involve the introduction and admissibility of PV examination results as evidence in a court of law. However, compliance with the Federal Rules of Evidence by William Daubert v. Merrell Dow Pharmaceuticals, Inc., 113 S.Ct. 2786, 125 L.E.2d 469, 509 U.S. (1993) which superseded the Frye standard (Frye v. United States, 54 App. D.C. 46, 47, 293 F. 1013, 1014 [1923]), may still be required for acceptance of the results of a PV examaintion, even though the resutls are not being formally offered in a court of law.

Plea Bargaining: Even inadmissible PV examination results can be used to bargain with the prosecution for a lesser charge or outright dismissal. Verification of the essential elements of information in the subject's version of the incident will prevent unnecessarily lengthy investigations into sometimes incredible versions, when the other evidence against the subject is overwhelming and a very appealing offer by the prosecution is available if the case is resolved by a negotiated plea.

Motions to Suppress Evidence: Conflicting testimony between the defense attorney's client and the arresting officer concerning the legality of a search and/or advisement of his or her rights can be resolved by the administration of a PV examination.

Settlements: Acceptance of PV examination results prior to trial often results in settlements, thereby saving the time, expense, agony and embarrassment of a trial.

Sentencing: PV examination results may be used to disprove unfavorable information found in presentencing reports that was not used to arrive at a guilty verdict, or to determine the veracity of a convicted subject's assertion of assets which may be an issue at sentencing.

Supporting Evidence: Quite often, a criminal defense depends upon psychiatric opinion testimony as to the defendant's ability to understand the charges and assist in his or her defense or his or her legal culpability for actions he or she may have committed. The opinions of the expert witness in this area often depend heavily upon statements made to the expert by the defendants. Prosecutors often attack the expert's opinions by challenging the truthfulness of the defendant's statements. The PV examination used in conjuntion with a psychiatric examination can provide the expert with verified information upon which to base his or her opinion.

Parole and Probation: The PV examination can be an invaluable aid in verifying the accuracy of information to be used as a basis for granting or revoking parole or probation. In fact, several states have adopted a program of monitoring sex offenders with the use of PV examinations as a condition of their parole or probation. (See Chapter 24 of Forensic Psychophysiology Using the Polygraph [Matte 1996].)

Arbitration: Forensic psychophysiology has been successfully used in federal and state arbitrations to resolve conflicting testimony.

Civil Actions: PV examination results can be used to resolve paternity suits, effect marital reconciliation, settle child custody and visitation right disputes, and determine the veracity of accusations often made in domestic relations cases. Disputes in automobile accidents or transactions between businessmen can also be resolved by the use of PV examinations.

The benefits that the attorney will derive from the use of the psychophysiological veracity (PV) examination are by no means exhuasted. The bulk of his or her practice involves a constant effort to verify those facts that will further his or her cause. Awareness of the utility of forensic psychophysiology will open new vistas for the attorney in his or her daily practice.

The defense attorney who intends to introduce PV examination results as evidence in a court of law on behalf of his or her client must realize that the supersedence of the Frye standard in favor of the Federal Rules of Evidence by William Daubert v. Merrell Dow Pharmaceuticals is merely an invitation for forensic psycholphysiology to show that it is worthy of acceptance by the court. It therefore behooves the attorney who has such an aspiration to present to the court a most competent and well-prepared forensic psychophysiologist, whose expert testimony is preceded by the scientific testimony of a foundation expert, and whose results (of the PV examination) are confirmed by a qualified quality control reviewer.

The terminology used in forensic psychophysiology has recently undergone significant changes, which the attorney and testifying experts should familiarize themselves with by consulting the latest textbook and its glossary of terms in Forensic Psychophysiology Using the Polygraph (Matte 1996). (See also the Glossary of Terms in this book.)

The term polygraph examination, which has been widely used for the past six decades by the polygraph community and the media, has now been replaced by the Department of Defense Polygraph Institute (DoDPI) with the term psychophysiological detection of deception (PDD) (Yankee 1994), but this author prefers and has adopted the more appropriate term of psychophysiological veracity (PV) examination inasmuch as we verify the truth as well as detect deception, and the presumption of innocence must prevail throughout the PV examination process as a scientific requirement as well as a legal obligation to the examinee. The forensic psychophysiologist's objective is to seek the truth. The terms polygraph examiner or operator and polygraphist were replaced by the DoDPI and this author with the term forensic psychophysiologist. However, DoDPI subsequently reverted back go the term polygraph examiner due to some government examiners not possessing an academic degree related to that discipline. Nevertheless DoDPI retained the term forensic psychophysiology to describe its discipline. The term forensic describes and limits the application of psychophysiology to the legal system. The term psychophysiology refers to the psychological structure of the PV examination (psycho-), and the collection, analysis and quantification of the physiological data (-physiology). Thus forensic psychophysiology is a science that applies psychophysiological vercity examinations to the legal system. [Fn 2] The term forensic psychophysiology has also been adopted by the American Society for Testing and Materials (ASTM) after a full consensus ballot of the term and its definition had been approved by the ASTM committee on standards.

A distinction is made between the terms examination and test. A psychophysiological veracity examination is a complex, wholistic system (Crews 1993) encompassing the entire examination, which includes all parts of the pretest interview, and includes the formulation of test questions, their review and presentation and assurance of intended interpretation, as well as the conduct of the psychophysiological veracity test(s) for the collection of physiological data resulting in polygraph charts, which are analyzed and quantified for a determination of truth or deception. These tests can include the administration of an acquaintance test, a control-stimulation test, a silent answer test, and a control question test, all within the same psychophysiological vercity examination to resolve a single issue on t e same examinee. As will be seen in Chapter 4 and the scripts of the experts (Chapters 6, 8 and 10) set forth herein, the pretest interview and the psychological structure of the test(s) are designed to address known impeding variables; [Fn 3] thus procedural violations during any portion of the examination process, which may introduce unknown impeding variables, must be avoided. Hence, this wholistic system (examination) includes all of the aforementioned interacting parts, any one of which if omitted or altered affects the psychophysiological test results. The whole is the sum of its parts and the interactions of its parts which work together synergistically.

As will be recognized in the discussion of the PV examination structure in Chapter 3, there is a need for the entire PV examination process to be video recorded or at the very least audio recorded for preservation and availability to the court. This permits all parties to review the entire PV examination for evidence of procedural violations which may affect the test results. Scientific and legal justification for this recommended requirement may be found in Matte (1993); Krapohl (1998); and Chapter 23, Part III, of Forensic Psychophysiology Using the Polygraph, Mattee (1996).

Interestingly, in United States v. Hart (ED NY) 344 F Supp 522 (1971) the court ruled that the government had a duty to supply the results of the polygraph examination of its star witness to the defendants, and the tests' results would be admissible, so that the jury could evaluate the credibility of the government's witness (Sevilla 1977). Hence the need to record the entire PV examination on video tape for subsequent review by opposing counsel had become a necessity, inasmuch as its absence would prevent a significant reconstruction of the PV examination process.

The polygraph instrument, often referred to as a machine, which it is not, is a diagnositc tool which comprises at the most ten percent of the PV examination process. Yet much greater emphasis has been placed by the legal community on the instrumentation used than on the type of psychological technique and methodology employed to generate the physiological data recorded by the polygraph instrument. Many attorneys have readily accepted the nation that the computerized polygraph systems are superior to the electronic analog polygraph instruments in their physiological recording capability and in the algorithms used to interpret and evaluate the recorded physiological data. However, as of this writing, the analog instruments produce somewhat purer and more distinct tracings of the physiological data than the computerized instruments, which allows for better manual scoring (see Chapter 9, Part A, Sec.[1[[b[ of this book), and the well-trained and experienced forensic psychophysiologist still outperforms the computer algorithm in at least true [Fn 4] single-issue control question tests, which have been validated, as the most accurate tests in the arsenal of the forensic psychophysiologist. In fact, leading experts in the field of forensic psychophysiology recommend that "At the present time, the currently available computer algorithms are in a continuing stage of development and refinement and thus should be supported by the manual scoring of the physiological data recorded on the polygraph charts." (Matte 1996, p. 428).

The current electronic analog and computerized polygraph instruments still record the same physiological parameters (respiration, electrodermal, and cardiovascular activity) as did their predecessor, the mechanical polygraph instrument. However, significant improvements have been made in the recording components of the electronic and computerized polygraph instruments, which render most physiologically and mentally fit subjects testable. Furthermore, more polygraph research has been published in the last fifteen years than in the preceding sixty years of existence since the Frye standard was established in 1923. (Frye v. United States, 293 F. Court of Appeals of District of Columbia. Decided 8 December 1923). There is no doubt in the scientific community about the validity and reliability of the polygraph instrument currently being used in the field.

Of greater importance is the amount of published research on psychophysiological veracity (PV) examination techniques. As reflected in Chapter 3 of this book, which goes into greater detail, of the eighty (80) research projects published since 1980 on psychophysiological veracity examinations, twelve (12) studies of the validty of field examinations involving 2,174 field examinations provided an average accuracy of 09% (Ansley 1997). It should be noted that twice as many laboratory studies were conducted as field studies, most likely because laboratory studies are conducted in academia with restricted budgets but available students for mock crime experiments. The lack of funds or availability of a professional forensic psychophysiologist is another factor as well. The fourty-one (41) studies involving the accurage of 1,787 PV examinations in laboratory simulations procuded an average accuracy of 80% (Ansley 1997). This should not surprise anyone inasmuch as laboratory (analog) studies lack three essential emotions present in field studies; fear of detection by the guilty, fear of error by the innocent, and anger. Chatper 3 of this book, which is a micro reflection of Chapter 3 in Forensic Psychophysiology Using the Polygraph (Matte 1996), provides the necessary research data for use as a basis for the foundation testimony.

The Script of Foundation Testimony (Chapter 6) is designed for use not only by qualified forensic psychophysiologists, but also by physiologists, biologists, psychologists, and psychophysiologists who have had no formal training and/or experience in the conduct of psychophysiological veracity examinations, but have participated in published research directly related to forensic psychophysiology using the polygraph, and have an intimate knowledge of the physiological and psychological aspects of the psychophysiological veracity examination being proffered. The fouindation testimony is followed by the testimony of the forensic psychophysiologist who conducted the PV examination being proffered. When the instant PV examination has been reviewed by a quality control reviewer, which is highly recommended, then his/her testimony normally follows that of the forensic psychophysiologist who conducted the PV examination. The importance of having a second opinion by a qualified expert forensic psychophysiologist in cases where the PV examination results are being offered into evidence in a court of law has been amplified with the adoption of its requirement into the Standard Practice for the Quality Control of PV Examinations by the American Society for Testing and Materials (ASTM), which will become the international standard on forensic psychophysiology. The quality control reviewer must be a graduate of a polygraph scoool accredited by the American Polygraph Association who has successfully served the school's required internship, and has at least five years of experience in the conduct of PV examinations. The more experience and attendance at continuing education schools and/or courses, the better his/her testimony will be received and valued.

The qualify control reviewer (QCR) may also serve as the foundation expert if he/she meets the education and publication requirements listed in Chapter 5 of this book. The qualified forensic psychophysiologist who conducted the proffered PV examination may also serve as the foundation expert if he/she meets the education and publication requirement listed in Chapter 6 [Fn. 6]; however he/she still needs the testimony of a QCR to confirm external reliability.

The cross-examination of the forensic psychophysiologist who conducted the proffered PV examination is usually far more vigorous than that of the foundation expert. Nevertheless both types of experts should be prepared for the unexpected, and be well prepared prior to giving their testimony. Chapters 7 and 9 should be useful in that regard.

The admissibility of confessions in PV examinations varies with different jurisdictions. Chapter 12 discussses some of the decisions rejecting confessions, and methods that may reduce and/or avoid problems associated with the acquisition of confessions resultingin their inadmissibility in court.

I hope that this book will ease the task of the attorney at law in deposing his/her expert witnesses, and that the aforementioned experts will find the information contained herein, especially the scripts, most useful in establishing a proper foundation for the admissibility of psychophysiological veracity examinations using the polygraph.

References Omitted


  1. Forensic Psychophysiology Using the Polygraph: Scientific Truth Verification--Lie Detection. (1996) James Allan Matte, Ph.D.: Williamsville, NY: J.A.M. Publications.
  2. The attorney should not confuse voice stress analyzers such as the CVSA with the polygraph instrument. On 11 September 1996, the Department of Defense Polygraph Institute (DoDPI) issued a Position Statement on voice stress analysis including the CVSA which states "To date, we have found no credible evidence in information furnished by the manufacturers, the scientific literature, or in our own research, that voice stress analyhsis is an effective investigative tool for determining deception." (Capps. 1996). For more information on voice stress analyzers, see Forensic Psychophysiology Using the Polygraph (Matte 1996).
  3. Identified impeding variables are listed and explained in Chapter 9, Forensic Psychophysiology Using the Polygraph: Scientific Truth Verification--Lie Detection (Matte 1996).
  4. Some polygraph techniques have been labeled as single-issue tests even though they contain an evidentiary or other secondary relevant question, which truly renders the test a multiple-issue test.
  5. In People v. Brown (1985) 40 Cal3d 512, 533 (220 Cal Rptr 637), which involved typing of semen stains by electrophoresis, the State offered the testimony of two Department of Justice criminalists who had analyzed the stains. The court stated that: "[They] were competent and well-credentialed forensic technicians, but their identification with law enforcement, their career interest in acceptance of the tests, and their lack of formal training and background in the applicable scientific disciplines made them unqualified to state the view of the relevant community of impartial scientists." In this instance the criminalists were technicians, not scientists. Furthermore, most scientists qualified to lay the foundation for the admissibility of polygraph results are expert forensic psychophysiologists. The notion that a scientist should be disqualified as a foundation expert due to his expertise as a forensic psychophysiologist because of his/her inherent "career interests" would not only be impractical but would also be inconsistent with the fact that the party attempting to introduce polygraph evidence in court would most certainly not select a scientist opposed to admissibility, thus an implied bias. The foundation expert does not offer testimony regarding the validity and reliability of the results of the PV examination to be offered into evidence. That is the function and responsibility of the forensic psychophysiologist who conducted the PV examination and the Quality Control Reviewer who evaluated the instant PV examination.