INTERPRETATION OF THE TEST

A polygraph examination is designed to detect physiological responses to stimuli in a carefully controlled interrogation. Such responses may accompany and indicate deception.[A17-89] The polygraph instrument derives its name from the Greek derivative “poly” meaning many and the word “graph” meaning writings.[A17-90] The polygraph chart writings consist of three separate markings placed on a graph reflecting three separate physiological reactions.[A17-91] A rubber tube is placed around the subject’s chest to record his breathing pattern on a pneumograph.[A17-92] That device records the respiratory ratio of inhalation and exhalation strokes.[A17-93] The second component is called a galvanic skin response which consists of electrodes placed on the examinee’s fingers, through which a small amount of electrical current is passed to the skin.[A17-94] The galvanometer records the minute changes in electrical skin response.[A17-95] The third component consists of a cardiograph which is a tracing obtained by attaching a pneumatic cuff around the left arm in a manner very similar to an apparatus which takes blood pressure.[A17-96] When the cuff is inflated, that device records relative blood pressures or change in the heart rate.[A17-97]

From those testing devices, it is possible to measure psychological or emotional stress.[A17-98] This testing device is the product of observation by psychologists and physiologists who noted certain physiological responses when people lie.[A17-99] In about 1920 law enforcement officials with psychological and physiological training initiated the development of the instrument to serve as an investigative aid.[A17-100]

The polygraph may record responses indicative of deception, but it must be carefully interpreted.[A17-101] The relevant questions, as to which the interrogator is seeking to determine whether the subject is falsifying, are compared with control questions where the examiner obtains a known indication of deception or some expected emotional response.[A17-102] In evaluating the polygraph, due consideration must be given to the fact that a physiological response may be caused by factors other than deception, such as fear, anxiety, nervousness, dislike, and other emotions.[A17-103] There are no valid statistics as to the reliability of the polygraph.[A17-104] FBI Agent Herndon testified that, notwithstanding the absence of percentage indicators of reliability, an informed judgment may be obtained from a well-qualified examiner on the indications of deception in a normal person under appropriate standards of administration.[A17-105]

Ordinarily during a polygraph examination only the examiner and the examinee are present.[A17-106] It is the practice of the FBI, however, to have a second agent present to take notes.[A17-107] It is normally undesirable to have other people present during the polygraph examination because the examinee may react emotionally to them.[A17-108] Because of the numerous interested parties involved in Ruby’s polygraph examination, there were present individuals representing the Commission and the Dallas district attorney, as well as two defense counsel, two FBI agents, the chief jailer, the psychiatrist, and the court reporter, although the assistant district attorney and one defense counsel left when Ruby was actually responding to questions while the instrument was activated.[A17-109] Ruby was placed in a position where there was a minimum of distraction for him during the test.[A17-110] He faced a wall and could not see anyone except possibly through secondary vision from the side.[A17-111] Agent Herndon expressed the opinion that Ruby was not affected by the presence of the people in the room.[A17-112]

Answer by Ruby to certain irrelevant control questions suggested an attempt to deceive on those questions. For example, Ruby answered “No” to the question “While in the service did you receive any disciplinary action?”[A17-113] His reaction suggested deception in his answer.[A17-114] Similarly, Ruby’s negative answer to the query “Did you ever over-charge a customer?” was suggestive of deception.[A17-115] Ruby further showed an emotional response to other control questions such as “Have you ever been known by another name”[A17-116] “Are you married?”[A17-117] “Have you ever served time in jail?” [A17-118] “Are your parents alive?”[A17-119] “Other than what you told me, did you ever hit anyone with any kind of a weapon?”[A17-120] Herndon concluded that the absence of any physiological response on the relevant questions indicated that there was no deception.[A17-121]

An accurate evaluation of Ruby’s polygraph examination depends on whether he was psychotic. Since a psychotic is divorced from reality, the polygraph tracings could not be logically interpreted on such an individual. A psychotic person might believe a false answer was true so he would not register an emotional response characteristic of deception as a normal person would.[A17-122] If a person is so mentally disturbed that he does not understand the nature of the questions or the substance of his answers, then no validity can be attached to the polygraph examination.[A17-123] Herndon stated that if a person, on the other hand, was in touch with reality, then the polygraph examination could be interpreted like any other such test.[A17-124]

Based on his previous contacts with Ruby and from observing him during the entire polygraph proceeding, Dr. William R. Beavers testified as follows:

In the greater proportion of the time that he answered the questions, I felt that he was aware of the questions and that he understood them, and that he was giving answers based on an appreciation of reality.[A17-125]

Dr. Beavers further stated that he had previously diagnosed Ruby as a “psychotic depressive.” [A17-126]

Based on the assumption that Ruby was a “psychotic depressive,” Herndon testified:

There would be no validity to the polygraph examination, and no significance should be placed upon the polygraph charts.[A17-127]

Considering other phases of Dr. Beavers’ testimony, Herndon stated:

Well, based on the hypothesis that Ruby was mentally competent and sound, the charts could be interpreted, and if those conditions are fact, the charts could be interpreted to indicate that there was no area of deception present with regard to his response to the relevant questions during the polygraph examination.[A17-128]

In stating his opinion that Ruby was in touch with reality and understood the questions and answers, Dr. Beavers excepted two questions where he concluded that Ruby’s underlying delusional state took hold.[A17-129] Those questions related to the safety of Ruby’s family and his defense counsel.[A17-130] While in the preliminary session Ruby had answered those questions by stating that he felt his family and defense counsel were in danger, he did not answer either question when the polygraph was activated.[A17-131] Dr. Beavers interpreted Ruby’s failure to answer as a reflection of “internal struggle as to just what was reality.”[A17-132] In addition, Dr. Beavers testified that the test was not injurious to Ruby’s mental or physical condition.[A17-133]

Because Ruby not only volunteered but insisted upon taking a polygraph examination, the Commission agreed to the examination. FBI Director J. Edgar Hoover commented on the examination as follows:

It should be pointed out that the polygraph, often referred to as “lie detector” is not in fact such a device. The instrument is designed to record under proper stimuli emotional responses in the form of physiological variations which may indicate and accompany deception. The FBI feels that the polygraph technique is not sufficiently precise to permit absolute judgements of deception or truth without qualifications. The polygraph technique has a number of limitations, one of which relates to the mental fitness and condition of the examinee to be tested.

During the proceedings at Dallas, Texas, on July 18, 1964, Dr. William R. Beavers, a psychiatrist, testified that he would generally describe Jack Ruby as a “psychotic depressive.” In view of the serious question raised as to Ruby’s mental condition, no significance should be placed on the polygraph examination and it should be considered nonconclusive as the charts cannot be relied upon.[A17-134]

Having granted Ruby’s request for the examination, the Commission is publishing the transcript of the hearing at which the test was conducted[A17-135] and the transcript of the deposition of the FBI polygraph operator who administered the test.[A17-136] The Commission did not rely on the results of this examination in reaching the conclusions stated in this report.

APPENDIX XVIII
Footnotes

For references to the testimony of witnesses before the Commission, the following citation form is used: number of volume, “H” (for “Hearings before the President’s Commission on the Assassination of President Kennedy”), page number, and the name of the witness in parentheses, e.g., 7 H 441 (O’Donnell). Commission exhibits are referred to by the capital letters “CE” and number; deposition exhibits by the name of the witness, the capital letters “DE,” and the number or letter of his exhibit, e.g., CE 705; Sorrels DE 1. References to audiovisual sources for one Dallas broadcasting station (WFAA) are cited as follows: PKT for video tapes, PKF for films, and PKA for audio tapes. The video and audio reels and tapes of other stations are cited by number, e.g., WFAA-TV reel PKT 10; KBLD-TV reel 13.