if Approved For Release 2001/03/07 : CIA-RBP96-0078 LIK DETECTION THROUGH VOICE ANALYSIS By Frederick C. Link* "Have you read the articles on voice analysis in recent Playboy™ and Penthouse* magazines?" "Have you seen the movie 'The Trial of Billy Jack?" "Or, have you watched television presentations on ‘What voice analysis shows really happened in the Kennedy assassination.'" If the answer to any one of these is "yes," you may well have been left with the impression that voice analysis is the cure-all for detection-of— deception problems in law enforcement. Lie detection through voice analysis has been glamorized by publicity in the popular media, and all this glitter has led many citizens to form an un— realistically high opinion of the present value of voice analysis. However, television, movies and popular magazines have not given unbiased, impartial #resentations of the facts regarding the effectiveness of voice analysis for Hie detection. At the present time, no military law enforcement agency is using voice analysis for lie detection, although all of these agencies use the polygraph technique when it is appropriate. There are good reasons for this nonuse of voice analysis. While voice analysis may some day in the future be devel~ vped to the point where it is useful for military lie detection, that day has not yet arrived. In order to understand why this is so, let us look at some pertinent facts. The Basis of Voice Analysis Although human speech is the result of a very complicated process, several different aspects of the voice can be analyzed. The manufacturer of one voice zenalysis device (the Psychological stress Evaluator) relates that the Single, Y/Y integrated sound that we hear as human speech is composed of at least three different sounds blended together: the basic sound, formant sound, and the microtremor. The basic sound is formed by air being forced over the vocal cords and is a signal generally between 100 and 300 hertz, (1 hertz, a frequency equal t one cycle a second). This frequency forms the base of the combined signals tnat constitute the voice. 4 “the author is a Chief Warrant Officer, Corps of Military Police, U.S. Army, and an instructor in polygraph technique in the Army Polygraph School av Fort McClellan, Ala. The article is reprinted from the Military Police Low Enforcement_Journal, Spring, 1976, with permission of the journal and the adathor. 163 Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2
Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2 The formant sounds are resonances (vibrations) created by the various cavities of the head, especially the mouth, _ Which add a second amplitude- modulated sound to the voice. Finally, the microtremor (an inaudible frequency modulation) is super imposed on the base and formant sounds. FM meet ts | The microtremor signal is normally in the range of 8 to 12 hertz andj it \, is present in all normal speech. However, when a speaker begins to feel ‘in- | ternal stress and those speech processes that are normally mediated by tis | | | | | wee autonomic nervous system are brought under conscious control, then the micrc- tremors are suppressed and disappear from the voice. When this presence or absence of the microtremor is recorded and charted with suitable equipment, it is possible to determine from speech whether a speaker shows stress. Under suitable testing conditions, the presence of stress would_be an indication of lying, and the absence of stress would show truthfulness. Another voice analysis device, the Mark II Voice Analyzer, is claimed to function by extracting and processing the trenmlo effect from the voice, a process rejated to but not the same as that used in the Psychological Stress Evaluator. Dt gt gag MAA EE REN ge ; Voice analysis devices have been highly marketable and they have been ly popping up like mushrooms. Although these devices differ from each other in i their exact modes of operation and in their finished designs, they are all | essentially similar in that they extract and process some signal contained in speech. The devices offered by the manufacturers range in price from about $3,500.00 up. Usually, these systems consist basically of a tape recorder; the analyzer itself, which gives a chart readout and, in at least one case, | a numerical readout and the accessories such as microphones, telephone tcfos, ‘ and the like. nl . *. : pee TA oe: ce pee Does Voice Analysis Really Work in Lie Detection? The manufacturers of these devices, of course, claim that they really work. In fact, they claim them to be better than the polygraph in accuracy, reliability,.ease of use, comfort and dignity of the examinee, and in just about any other respect you can imagine. Additionally, the manufacturers: of some of the devices have gotten nation-wide publicity by claiming to have analyzed and determined the truthfulness of the recorded statements of such _ contemporary figures as Lee Harvey Oswald, Edward Kennedy, and Patty Hearst.” They further claim to have determined the truthfulness of the statements made by these persons. We will deal with these latter claims further on in 1 this paper. en ett ce 7 Military attitudes on voice analysis for lie detection are based on tes-s | of some of these devices made by several military agencies and on validatior research conducted by a civilian institution under contract to the Army. The Air Force tested a,Psychological Stress Evaluator for lie detection and found it "not useful.’ n6 The National Security Agency tested a Psychologica. Stress Evaluator and found it “insufficiently reliable."? The Army obtained three Psychological Stress Evaluators and used them in a study of lie detection nel MMIII TOOL DAG RTT Fert, : eT ae Pee 164 Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2
Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2 conducted by Dr. Joseph Kubis of Fordham University. Following this study, the Army dismantled two of the devices and transferred the third one to the Air Force for research in areas not related to the detection of deception. “the Kubis study ,? completed in 1973, provides the primary justification for the Army's nonuse of voice analysis. It is also a very interesting and 3 enlightening document on the relative effectiveness of the polygraph tech-— nique, voice-stress analysis, and investigator intuition. In essence, Dr. Kubis put a number of volunteers through a crime situation in which money was stolen from a purse. The volunteers were placed in groups of three in which3 one person stole the money, the second acted as a lookout, and the third . person had no connection with the crime whatsoever. After the crime had been committed, all three persons were tested to attempt to determine what their individual roles in the crime had been. In the structure of a polygraph ex- amination situation, the suspects were given a polygraph examination while at the same time their answers were tape-recorded. These tape recordings were ‘subsequently analyzed with two different voice analysis devices to attempt to determine each suspect's role. Finally, the examination was watched by ob— ‘servers who attempted to tell if the suspects were lying or telling the truth - just by looking at them and interpreting their actions. Kubis' study concluded that the polygraph technique had high validity, observation of behavior was second most effective in determining who did what, and voice analysis came off a poor third in detecting deception in this ex- periment. In the words of Dr. Kubis: "Essentially, the findings indicated the clear inferiority of voice analysis in its present state of development, not only to the polygraph but also to judgments made on the basis of simply observing subjects! behavior." He further says: "The results failed to demonstrate that either of the voice-analysis techniques was effective in identifying the three basic roles of thief, lookout, and innocent suspect in the simulated theft. In contrast, the polygraph achieved an accuracy score of 76 percent, a value comparable to that obtained in previous studies using the simulated theft paradigm." This validation effort provided the militaiy community with a scientifically researched basis for rejecting voice analysis as a lie detection technique at this time. Dr. Kubis does not conclude that voice analysis for lie detection is unworkable, only that presently availabie voice analysis equipment does not fill the bill. He attributes the failure of voice analysis in his experiment to "ga matter of insensitivity or other inadequacy in the devices themselves in their present state of development ."12 Perhaps someday in the future, voice analysis will be developed to the point where it is usable for lie de- tection. It should be noted that the manufacturers of the equipment and some of its users have criticized the Kubis study on technical grounds. These criti- cisms range from the claim that the tape recordings were of such poor quality they could not be analyzed to the claim that the requirements of the research contract were not met. Therefore, it is claimed that the results and con- clusions of the Kubis study are invalid. This appears to be a somewhat extreme position and there is probably little valid reason to doubt the over— all conclusions of the study. Nevertheless, a new validation study is being 165 Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2
‘Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2 conducted by a group at the Michigan State University, but so far no findings have been announced. Can Voice Analysis Determine If Public Figures Are Telling The Truth in Public Statements? Probably the most effective publicity for voice analysis has come from the media that ran sensational stories about the analysis of public statemen 4s made by newsworthy persons. The publicity centered primarily about the quest.ions of whether Lee Harvey Oswald shot President Kennedy, whether Oswald acted alfne, and whether there was a conspiracy among various unnamed persons acting to shcot Kennedy. The leading article on this subject was written by a trained voice analyst. The article, entitled "Lee Harvey Oswald Was Innocent , "14 appeared in the April 1975 issue of "Penthouse" magazine. It contained a quite de- tailed account of how the author had determined Oswald's innocence, and many other details of the Kennedy assassination, through voice analysis. Naturally, as indicated by the title of the article, the most significant conclusion wa: that Oswald was most probably telling the truth when he denied shooting Presi-- dent Kennedy. ; More recently, another prominent voice analyst was reported in the press) to have analyzed the tapes made by Patty Hearst while she was under the domina- tion of the Symbionese Liberation Army (SLA). This recognized authority on voice analysis concluded that Patty Hearst made all of her antisocial state- ments under duress. He said she was not telling the truth when she claimed to have voluntarily joined the: SLA and to have voluntarily participated in the bank robberies and other illegal activities perpetrated by the SLA. He said she was innocent of any voluntary wrongdoing, and was doing only what she was forced to do. All of these conclusions were formed on the basis of this authority's analysis of the Hearst tapes. On June 4 and 5, 1974, a subcommittee of the Committee on Government Operations of the House of Representatives of the United States held hearing on "The Use of Polygraphs and similar Devices by Federal Agencies." Various advocates of the voice analysis lie detection technique testified before this subcommittee. A position paper prepared by one manufacturer of voice analysis devices said: , Because the PSE uses the voice as a medium for stress measure— ment, the question has been raised concerning the ability to detect attempted deception of truthfulness from television or radio broadcasts. It is indeed a fact that the PSE can be used to determine the stress levels on the part of the speaker under these circumstances. However, as has been discussed previously, lie detection is an interpretative or analytical process which requires certain control elements to allow equating the stress indications to attempted deception, as opposed to any other stress cause. Without these controls, appropriate pre-test, properly structured examination, and post-test interview in- dications of stress remain just that. (sic) It would be in- teresting, indeed, if lie detection could be accomplished un- der such circumstances, but it cannot." 166 Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2
Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2 tne developer of another of the voice analyzers told the subcommit ommittees "While the Mark II can provide data . in dialog, our cxperience to date shows sheer ess occurring papcedinely complex area. Patterns of stress rosctd an » al present, we cannot be certain as to thes tons occur Therefore, we do not believe that the Mark IL e€ir meanings, instrument currently available can analyze ro th any other and determine deception based upon our present knowles eet Bee » 4 <t wes He also stated that: "se. We just dontt know eno ugh to be abl + what the patterns of tension in dialog meng vputhfully say to mak rn find support for whatever interpretation he wishes e from these patterns. This is very bad obviously,#l8° "2... For example, it has been s uggested t} ig to tape record a presidential news conference Peon tent bY ele~ logical stress in it. But unless he fhesttons fron a structured interview, it yosle be ge the sources. Was the en nostcal Stress derived from lying or oe pou ces € stress caused by a lie, an ang 2 other » an extraneous thought, Or a gas i ed il ewan produce psychological stress ,"19 eee Pasn? All could At these same hearings, th i . . : Sy © president of ‘ . society, who is also a medical, doctor, made this stator esis Professional} "Another charge that is made is that the _ _ Psychologi (SE tave PeE-101) gan and may be used in a clandestine tashroe® Te ator conversation off the bel phone, ana pandestine fashion, in a f onface, formal bestia altrced epee noney and off the television. Hayeysn eo ce achieve from these t sts ie t spreeture, the only evaluation that ou con’ or they are notes ests 1s that the individual you are talkin “t "ts ote evaluation could be undert enol this type of recording no type of tr Pe oesing or conviction, the r . ae Mee erson As Speaking with omot ¢ y tne recording will show stress i ereat emotion emotion or conviction."20 7 48 1% should, mirroring that subcommittee: "The system, the PSE as a lie detect dowi as a or cannot i the knowLedge of the individual because detection wonton very specific set of circumstances, which means a personal * 167 Approved For Release 2001/03/07 : CIA-RDP96-00788R002000150003-2 ee