Introduction to the Role of the Polygraph
Polygraphs, also known as lie detectors, have been used for decades as tools for law enforcement and investigatory purposes. These devices measure physiological changes in order to ascertain whether a person is being truthful or deceptive. Specifically, they track stress responses in the body associated with deceit such as blood pressure, pulse, respiration and galvanic skin response, which measures perspiration. Despite the popularity of polygraphs, their efficacy as reliable tools for the truthfulness of an individual has been widely debated and has ultimately been determined not to be reliable enough for admissibility in criminal cases. As a result, they are primarily used when both sides are consensually agreeing to the test before they enter into litigation. It’s crucial for both parties to agree to the use of a polygraph and fully understand how the results of those tests will be treated and what the cost will be.
In criminal courts, the primary concern is the protection of an individual’s constitutional rights, particularly the rights against self-incrimination. The Fifth Amendment of the Constitution provides an accused individual with a right to be free from self-incrimination. As a result , the courts have determined that an individual cannot be compelled to testify against him or herself and produce evidence that could incriminate them. Given the nature of a polygraph’s inquiry, individuals who take them face the possibility of confessing to crimes that could be incriminating. This has led the courts to deem polygraphs inadmissible in criminal courts.
In civil cases, however, there is no Constitutional provision providing an individual with freedom from self-incrimination. Thus, parties who are involved in civil disputes are free to either voluntarily contribute to a polygraph or to be compelled to take one as a part of the attempt to settle the dispute. While the results of a polygraph are not completely admissible in civil courts, they may be used in limited circumstances to impeach witness credibility in the event that the witness later provides conflicting statements that are inconsistent with the results of the test. Thus, there are several advantages and disadvantages to taking a polygraph test, and these must be weighed against the pros and cons evaluating the individual case.
How the Polygraph Functions
The polygraph measures physiological responses such as heart rate, blood pressure, sweat gland activity and respiration. These reactions are thought to be coupled with certain emotions, including fear, anxiety and grief. To obtain a baseline reading, the subject is asked control questions meant to elicit a neutral response for comparison. For example the examiner might ask, "Is today Tuesday?" Once a baseline is established, the subject is asked questions and their physiological response to each question is recorded.
Based on the premise that deceptive answers will produce physiological reactions, the examiner records and scores the exam. While experienced examiners are able to obtain reliable results, studies have demonstrated that their accuracy is not perfect. In one study, the reliability of specific examiners varied substantially from a 47 percent to a 93 percent accuracy rate. Factors such as the examiner’s level of training, the purpose of the test, the seriousness of the issue, the subject, as well as the scientific, legal and social ethics of the area in which the polygraph test is being administered also play a role in the accuracy of the readings.
Legality of Using a Polygraph
The legal admissibility of polygraph test results is a significant concern in both civil and criminal cases. The general rule is that courts do not allow the introduction of polygraph results as evidence. There are a number of rationales for this, including:
For these reasons, and the fact that most states look down on people who participate in or conduct polygraphs, it is often contentious in court to even mention the word polygraph.
Although the more enlightened judicial ideals of the 1970s and 1980s accepted polygraph results as evidence in certain types of cases, today the general view is that they are not reliable enough to be considered by judges and juries. The courts even go so far as to deem a polygraph operator who uses his or her expertise in the courtroom as a party, meaning that the polygraph operator’s legal offsetting factors (envy, reward, guiding, ability, and reason) apply to the polygraph operator as well.
A review of state admissibility standards indicates that only California, New Jersey, and Nebraska allow polygraph results to be admitted into evidence without qualification. Most states make polygraph results admissible only if certain threshold criteria are met, while even more states put up additional hurdles in order to consider the threshold criteria.
Before even entering into a polygraph examination, attorneys should review what the law is in the relevant jurisdiction, as well as try to find an expert who knows what will pass muster.
Jurisdictional Acceptance of the Polygraph
The acceptability of polygraph evidence in court differs broadly from state to state and country to country. Most jurisdictions completely exclude polygraphs or admit them only for purposes of a preliminary examination.
In the United States, polygraph usage is governed by state law, which is frequently influenced by federal laws and regulations as well as the U.S. military’s rules on polygraphs. The prevailing federal statute, the Employee Polygraph Protection Act of 1988, excludes pre-employment polygraphs, limiting their use to criminal cases or national security threats. Although this statute effectively covers most private employment situations, some still fall under the purview of state laws or executive orders.
However, even when state law allows polygraphs under certain conditions, courts may still refuse to admit the evidence for either relevance or reliability issues. Due to their potential unreliability, polygraphs are inadmissible in nearly all states for civil or criminal proceedings. Exceptions include the District of Columbia, Massachusetts, Nevada, New Jersey, Oregon, and Tennessee, which have established "per se" exceptions to the federal statutory exclusion, as discussed below. In the District of Columbia, for example, polygraphs are only admissible if both parties stipulate thereto in writing, but such stipulations are not usually entered into (though they are very common in civil cases), resulting in minimal uses in D.C. The District Court overturned an earlier ruling that allowed such polygraph testimony in civil matters. Today, this issue is currently pending with the D.C. Court of Appeals.
Federal Rules of Criminal Procedure, Rule 12.2 extends the exception for criminal prosecutions to crimes under the Uniform Code of Military Justice, provided that each party stipulates in writing to the test. The Army and Air Force allow polygraph evidence subject to such a stipulation. Navy policy, however, requires the accused to waive their right to present evidence if they opt to take a polygraph test, i.e., they can use it as a sword and shield. The Army, Air Force, Coast Guard, and Marines file allegations of polygraph evidence, the decision being made within the command whether to present it or not. The decision regarding the admissibility of polygraph evidence in military tribunals turns on relevancy and reliability, which the court in United States v. Tovey subsequently went on to cite 43 Military Judges’ Manual of Court Martial (1998) at ¶ 9d(1) as the framework for assessing admissibility in non-military courts.
Although the federal district courts normally disallow polygraph evidence, in Cornett v. General Motors Corp., et al., the court allowed the polygraph as evidence of due diligence when the parties had agreed to the polygraph and agreed it could be relied upon as dispositive evidence in the litigation. This is consistent with the public policy permitting the admissibility of polygraph evidence in civil cases in Tennessee. The court in Union Carbide Corp. v. Farley, 785 S.W.2d 144 (Tenn. App. 1989) held that an employee who was given a polygraph test for a suspected violation of a company policy was due process entitled to the test results in defending against his employer’s action. As such, the court admitted the polygraph into evidence and the jury returned a verdict in favor of the employee.
In internationally, Germany’s approach is to allow wider admissibility of polygraph evidence within its judicial system while reserving the right to assess the credibility, proficiency, and choice of questions for the polygrapher. Australia recently set out its "Daubert-style" approach to polygraph admissibility in its decision in Regent Beverages Pty Ltd v Boral Ltd, which persuaded the Court of Appeal that they might consider the possibility of admitting the test results. However, New Zealand and Canada have chosen to follow the U.S. model in excluding most polygraph evidence.
Case Studies of Polygraph Use
Even courts that are willing to allow polygraph results into evidence typically look at the specifics of each case to determine if the circumstances rise to a level acceptable to allow the evidence to be used. In 2015, for instance, a mother unsuccessfully appealed a decision that a report from Michigan’s Department of Health and Human Services (DHHS) should not have been admissible because it relied on an unreported, non-validated polygraph in support of its conclusions against the mother. The mother’s objection was denied by both the trial court and the state Court of Appeals, which noted that there was no error in admitting the report because the "trial court was free to weigh the credibility of the report’s findings."
Conversely, a refusal to allow polygraph results into evidence even when both parties agreed to allow them was deemed an abuse of discretion by a panel that included now-Justice Joan Larsen in 2014. In that case, a federal court in Michigan had ruled in favor of the plaintiff based on an unwitnessed report by a polygraph expert that had tested the defendant , but didn’t allow the live testimony of the expert because the state he was purportedly from could not be substantiated. Upon appeal, the Sixth Circuit reversed the lower court’s ruling, in part based on the fact that "the district court denied [the defendant] the hearing [he] sought and the jury the hearing it demanded" and did "not explain its refusal to permit live testimony".
Not all cases have been found to outflow such positive results for the victims of wrongful accusations. In 2012, as discussed above, a decision by the Oregon Supreme Court found that members of a criminal defendant’s family could not be questioned using a polygraph and that FBI rules excluded the use of polygraph tests in interviews of federal criminal suspects unless all parties explicitly consented to their use. In 2015, a Washington appellate court found that a $5.5 million verdict against Boeing failed because a single question asked about in a polygraph test was deemed to be ambiguous and inadmissable, and thus the case was remanded for a new trial.
The Controversy: Reliability and Debate
A number of experts have publicly expressed doubt about the accuracy of polygraphs, pointing to the risk of false-positive results. In a 2012 article for the New York Times, journalist Tara Parker-Pope cited a study out of the Department of Defense Polygraph Institute, which "found that neither scientists nor computer algorithms performed a better job than a typical individual in judging the honesty or dishonesty of a subject…. ‘Nor did the overall accuracy of the "scientific" veracity judgment increase over time (i.e., were scientific advancements in terms of accuracy made in 30 years of research?).’ "
An article authored by experts in legal medicine in 1983, cited by Psychology Today to illustrate the long history of criticism directed at polygraphs, is far more scathing. "The weight of available evidence has led some investigators to conclude that the PCT [principal component analysis] is not a valid basis for assessing guilt or innocence, since many innocent subjects are classified as ‘guilty.’ " The psychiatric professionals continue, "Two recent reviews of the PCT point out the existence of substantial false positive classifications; that is, innocent persons are declared guilty. They conclude that the PCT is of questionable value for screening persons charged with a crime."
However, the use of polygraphs as part of criminal investigations continues, according to Dr. Richard Ofshe, who is a retired sociologist and criminal defense expert. He told Time magazine, "The reality is that law-enforcement agents and prosecutors know that—despite the [polygraph’s] supposedly infallible science, which is nonsense—they can steer investigations in directions favorable to the investigation…. Often, the person they are investigating makes a clean breast of it on polygraph because the agency that is investigating them doesn’t want to do an investigation to find out who really committed the crime."
Polygraphs in the Future
As with any other technology, polygraphs may undergo improvements that could influence their admissibility in the courtroom. For instance, as more sophisticated and accessible biometric data collection devices become mainstream, investigators may be able to offer even stronger evidence of culpability or innocence. Instead of reading brain waves or perspiration, they may read brain patterns or sweat glands. Increased knowledge about how the brain works may also allow scientists to develop more accurate models of inconsistent responses that will aid in making sound judgments about when and how to question a suspect. Furthermore, the law will evolve and react to emerging technologies. The intersection of law and technology has always been dynamic and continues to move at breakneck speed. As technology evolves, so will legal standards on privacy, fairness, and justice, including standards and case law applicable to interrogation and lie detection.
Conclusion to Polygraph Usage
The admissibility of polygraph evidence in court is a complex topic, often mired in state-specific regulations and legal precedents. The fact that these tests are only "generally inadmissible," meaning some courts do accept them in certain contexts, adds to the confusion. However, it’s clear that polygraph evidence may not be used during discovery or trial in most jurisdictions, and can only impact a case in specific circumstances. For example, you may learn about an individual’s passing or failing a lie-detector test. In this instance, if your client has taken a polygraph, evidencing that he’s vetted out her story, you can request that this information be considered when parsing out the facts of the case. If your client successfully passed a lie detector test, you can request that this information be submitted to the jury for consideration. However, be prepared to provide specific details of the test to the judge—what questions were asked? When? How accurate is the test? The judge will likely want to know—and may seek to impose restrictions on how this information can be used in court. If not upfront and honestly approached with fact-centric motives , the layperson’s obsession with lie detector tests might aggravate a jury, compelling them not to believe anything a defendant says under any circumstances. In that scenario, you’re adding more difficulty to your case than you are accomplishing through polygraph use. When exploring options concerning the use of lie detector testing in your case, discuss potential motivations behind the request with your client. Is the reason for your use of a polygraph legitimate? Are you confident that the results of this test correlate to your client’s claims and case? Your job is to represent your client—but if you have the slightest feeling that the use of the polygraph is inappropriately motivated, foregoing this practice may be advisable. Ultimately, polygraphs can (and often do) play an important role in factual development. Still, this does not mean their use is advisable in every case. When entertaining the idea of requesting or employing a polygraph in an action, counsel will serve themselves and their client best by closely evaluating not just the potential usefulness of such a measure, but also its potential for prejudicing and complicating the case.
