The use of polygraphs, voice stress analyzers, and forensic testing in sensitive areas, such as the questioning of suspects in criminal cases, recruitment processes (e.g. by the FBI), investigation of insurance fraud and interrogation of current or potential employees raises certain ethical issues. In particular, the appropriateness of compelling, or coercing people to undertake such testing needs to be examined. The use of polygraphs also raises the broader question of whether we want to live in a society that is dominated by these types of testing. Voice stress analyzers, unlike polygraph, are 98 percent accurate. These devices are so efficient and accurate, that many government agencies now use them. The major problem today in our criminal justice system is prosecutorial misconduct, consisting of hiding information to prosecuting those known to be innocent. The latter results in some 20 percent of our two million-inmate populations having not committed any crime. Despite this inherent difficulty in the relationship between psychology and the law, the forensic psychologist can assist a court or an investigation by giving an expert opinion on aspects of behaviour that will increase the probability of the outcome being correct; (i.e. can assist in avoiding miscarriages of justice). Forensic psychology, voice stress analyzers, and polygraph testing both in the mental health area and in other broader areas of behaviour have a body of knowledge that is of major value to the justice system; however, these issues have raised many controversies regarding its validity to the judicial system.
The validity of polygraph examinations to detect deception has long been a controversial issue. Since development of polygraph techniques almost 80 years ago, their use both within and outside the Federal Government has been the focus of numerous judicial opinions and, as well, legislative and executive branch debates. A Polygraph or lie detector is an instrument used to measure the autonomic nervous system responses in terms of blood pressure, pulse rate, respiration rate and galvanic skin response. In theory when a person tells a lie, fear of detection causes uncontrollable reactions in these physiological areas, which the polygraph indicated with inked lines on a moving paper scroll. Polygraph examinations have been approved as a way to determine guilt of criminal suspects, to exonerate innocent suspects, to protect national security, and to maintain employee honesty. Polygraph examinations have, at the same time, been criticized for providing inaccurate and misleading information, for failing to detect security risks, for interfering with the rights of private citizens, and for lowering employees morale. At the center of controversy over the use of polygraph examinations is the question of its validity: does a polygraph examination actually identify truthful and non-truthful individuals?
The most obvious concern is tat lie detectors do not actually tell you whether the subject has lied but rather deed on physiological responses recorded during the questioning of a person. An example of where polygraphs can give erroneous results is when nervous persons are tests. Person of a nervous disposition may display galvanic responses, which may be interpreted as indicating that the person Is lying when they are answering questions truthfully but are feeling stressed. Others are able to beat the lie detector. One method may be for a person to state a proposition numerous times until the person accepts its validity and consequently passes a lie detector test (e.g. the earth is square, the earth is square).
When courts have been called on to resolve disputes concerned with use of polygraph examinations, they have had to consider both the techniques validity and whether its use, however valid, interfaces with other values that the law seeks to protect. Indeed, for many years, the leading case on the admissibility of novel scientific evidence (Frye v. United States) was a case about the admissibility of polygraph evidence, and the opinion centered on the question of validity. The issue of how a court is to decide the question of any scientific techniques validity has brought the Frye test into question in recent years and makes striking the problem of establishing judicial standards for assessing validity.
The Frye v. United States case involved a 19-year-old defendant convicted of robbery and murder. Prior to his trial, a well-known psychologist and one of the originators of polygraph testing, Dr. William Marston, administered a systolic blood pressure test” to detect deception.
Dr. Marston determined, on the basis of this test, that Frye was truthful when he denied involvement in the robbery and murder. The trial judge, however, refused to permit Dr. Marston to either testify about the examination or conduct a reexamination using the blood pressure test in court. Frye appealed his conviction on the grounds that relevant exculpatory evidence had not been admitted. The appeals court; however, concurred with the initial trial court judgment. The court reasoned that the systolic blood pressure deception test was validated only by experimental” evidence and was not based on a well recognized scientific principle or discovery.” The decision stated that, while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the things from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs. Just when a scientific principle crosses the line between experimental and demonstrable is difficult to define.”
Ironically, Fryes conviction was later reversed when another man confessed to the crime, thereby providing Frye with more convincing corroboration of his denials of guilt. This did not settle the case; however, and recent discussion of the facts of the case indicate that Frye was, indeed, guilty. The crude polygraph examination conducted by Marston, thus, appears to have yielded an inaccurate conclusion. The Frye test is still used as precedent in most Federal courts. Subsequent opinions (in areas other than the polygraph) have tried to better define that line between experimental” and demonstrative” stages of a scientific innovation.
The preponderance of authority in the United States is against the admission of polygraph evidence with a variety of grounds having been asserted for refusing its admissibility.
It intrudes on the ultimate issue, which the Court must determine. It does not fulfil the criteria of the Supreme Court of the United States test in Frye Case with regard to admitting scientific evidence. It is hearsay evidence. It relates to the credit of witnesses not suffering psychiatric illnesses and is therefore not a proper matter for expert evidence. The elicitation of the responses is unfair because of the trickery and deceit necessary to obtain responses. The testimony is self-serving for the Defendant.
Central to legal, legislative, and scientific assessment of polygraph tests is their validity. Yet, despite many decades of judicial, legislative, and scientific discussion, no agreement has come forth about the accuracy of polygraph tests. It is extremely doubtful that polygraphs will ever gain general acceptance within the scientific community. There are simply too many reasons why polygraphs results or interpretations of test results may be flawed.
Police departments across the country are buying the controversial Computer Voice Stress Analyzer, which its manufacturer claims, can tell when a person is lying merely by the sound of his voice. When a suspect speaks, a computer program “listens” for minute vocal shifts that, in theory, indicate stress. The technology’s critics, citing government and university research, say the CVSA is little more than an electronic Ouija board with accuracy rates to match. At best, they say, voice stress analysis scares suspects into confessions; at worst, it can incriminate the innocent. CVSA results are not admissible in most courts, under the same Supreme Court decisions that generally bar polygraph evidence. In the Federal legal system, test results are inadmissible as substantive evidence. Whilst some States in the US have allowed test results in criminal trials. States such as California have prohibited the admission of such evidence unless all parties consent to its admission. Other States such as Illinois completely bar the use of such testing in criminal trials.
Even so, police officers love it. It is cheaper and faster than the polygraph, the CVSA can be operated with a few days’ training and without the need to “wire up” a suspect. It can also be used in the field, covertly, and on tape recordings, according to the National Institute for Truth Verification of West Palm Beach, Fla., its manufacturer. Between 1999 and 2000, NITV added 100 new customers. So far in 2001, NITV officials say nearly 300 police departments have bought at least one CVSA. Some have bought several, and nearly all “have put their polygraph on the shelf,” said David Hughes, a retired police captain and executive director of the company. Originating from a Cold War military project, voice stress analysis was first commercialized in the early 1970s.
The company’s Web site is replete with testimonials and success stories. One Alabama police department is said to have solved a murder case 14 years cold by re-interviewing the main suspect with the CVSA. The suspect had previously taken four polygraphs given by three different examiners, all inconclusive. Confronted with three failed voice stress tests, he broke down and confessed. Researchers counter that nothing in 30 years of studies proves that voice stress analysis works either generally or in the specific case of the CVSA. “Voice stress analysis is a fraud. It has zero validity,” said David T. Lykken, a psychology professor emeritus at the University of Minnesota in Minneapolis and author of the book “A Tremor in the Blood: Uses and Abuses of the Lie Detector.”
A 1996 Department of Defense Polygraph Institute study of the CVSA found that the device performs no better than chance in detecting deception. In other words, guessing or flipping a coin would be as accurate as the test. Based on this study, the Department of Defense, the Central Intelligence Agency and the Federal Bureau of Investigation do not use voice stress tests. Vincent Sedgwick says he was arrested in a rape case because of the test. In 1996, the Henderson, Nev., man had never heard of a voice stress lie detector. But, eager to clear himself of suspicion, he took the test, and failed. “When we’re done with the machine, (the examiner) tells me it looks like I’m lying,” Sedgwick said. “I was shocked. I had 100 percent faith it would clear me. It didn’t dawn on me until later that this thing is a sham.” Henderson police said in court filings that the arrest was based on evidence other than the CVSA results. Sedgwick was accused of being a lookout while a rape took place, but a judge threw out the charge for lack of evidence. NITV’s marketing materials claim a 98 percent accuracy rate for the CVSA, but company officials acknowledge that the figure is based on anecdotes from satisfied customers and not independent research.
In the United States of America, in England and in Scotland the legal systems use the expertise of the forensic psychologist in a variety of different ways that are outside the area of mental health. This use of a psychologist as only a source of mental health opinions closes off a number of potentially very valuable sources of information and evidence. Psychology is the study of behaviour (not only the pathology of behaviour) and from this wide knowledge-base a variety of skills can be used to assist legal professionals – both solicitors and barristers – in their work.
In Australia this does not appear to be the case as yet. There is major controversy over these matters in the Australian courts but in being cautious about admitting psychological evidence the courts are failing to give access to a source of information that is essentially valuable to the legal process. Psychology and the law, although both are intimately concerned with human behaviour, have a major difference in that the former sees behaviour in infinite shades of gray whereas the criminal law sees it in black and white – guilty or not guilty. Most criminal legal systems see and respond to behaviour in this simplistic but decisive manner. There is at least one exception to this in the Scottish legal system where a third verdict of “not proven” is possible. This is recognition by a judicial system that there are gray areas in human behaviour and that a simple guilty or not guilty model is not completely adequate. In civil law there is more recognition of the grayness of behaviour in such dimensional legal concepts as contributory negligence.
Despite this inherent difficulty in the relationship between psychology and the law, the forensic psychologist can assist a court or an investigation by giving an expert opinion on aspects of behaviour that will increase the probability of the outcome being correct; i.e. can assist in avoiding miscarriages of justice. Forensic psychology both in the mental health area and in other broader areas of behaviour has a body of knowledge that is of major value to the justice system.
There is considerable debated about the validity and accuracy of polygraph, voice stress analyzer, and forensic tests in the questioning of crime suspects and others and indeed about the validity of the techniques as a whole. In particular, the appropriateness of compelling or coercing people to undertake such testing needs to be examined. The uses of these devices also raise the broader question of whether people want to live in a society that is dominated by these types of testing.