Christopher Talbot thought he would make a great police officer. He was 29 years old, fit, and had a clean background record. Talbot had military experience, including a tour of Iraq as a US Marine, and his commanding officer had written him a glowing recommendation. In 2014, armed with an associate degree in criminal justice, he felt ready to apply to become an officer with the New Haven Police Department, in his home state of Connecticut.
Talbot sailed through the department’s rigorous physical and mental tests, passing speed and agility trials and a written examination—but there was one final test. Like thousands of other law enforcement, fire, paramedic, and federal agencies across the country, the New Haven Police Department insists that each applicant take an assessment that has been rejected by almost every scientific authority: the polygraph test.
Commonly known as lie detectors, polygraphs are virtually unused in civilian life. They’re largely inadmissible in court and it’s illegal for most private companies to consult them. Over the past century, scientists have debunked the polygraph, proving again and again that the test can’t reliably distinguish truth from falsehood. At best, it is a roll of the dice; at worst, it’s a vessel for test administrators to project their own beliefs.
Yet Talbot’s test was no different from the millions of others conducted annually across the public sector, where the polygraph is commonly used as a last-ditch effort to weed out unsuitable candidates. Hiring managers will ask a range of questions about minor crimes, like marijuana use and vandalism, and major infractions, like kidnapping, child abuse, terrorism, and bestiality. Using a polygraph, these departments believe, increases the likelihood of obtaining facts that potential recruits might prefer not to reveal. And like hundreds of thousands of job candidates each year, Talbot was judged to have lied on the test. He failed.
New Haven allows failed applicants to plead their case in public before the Board of Police Commissioners. So in February 2014, Talbot sat down and recited his experiences with lie detectors. He had first applied to the Connecticut State Police and was failed for deception about occasional marijuana use as a minor. He then tried again with a police department in New Britain, where a polygraph test showed him lying about his criminal and sexual history.
This time he had failed the New Haven polygraph for something cryptically called “inconsistencies.” “[But] I’m not hiding anything,” he said at the hearing. “I was being straight and honest and I’ve never been in trouble with the law. I’m not lying about anything.”
Electronic lie detection is a peculiarly American obsession. No other country carries out anywhere near the estimated 2.5 million polygraph tests conducted in the US every year, a system that fuels a thriving $2 billion industry. A survey by the Bureau of Justice Statistics from 2007 found that around three-quarters of urban sheriff and police departments use polygraphs when hiring. Each test can cost $700 or more. Apply to become a police officer, trooper, firefighter, or paramedic today, and there is a good chance you will find yourself connected to a machine little changed since the 1950s, subject to the judgment of an examiner with just a few weeks’ pseudoscientific training.
Last week the technology burst into the news when Christine Blasey Ford, the woman who accuses Supreme Court nominee Brett Kavanaugh of sexually assaulting her as a teenager, said that she had taken a privately administered polygraph test to help bolster her account of the incident. “While not admissible in court, they’re used by various governmental agencies and many people believe in their abilities,” Douglas Wigdor, a former prosecutor who now represents victims in sexual harassment and sexual assault cases against high-profile men, told The Washington Post.
In one of the biggest surveys of law enforcement use of polygraph screening to date, WIRED filed more than 50 public-records requests with America’s largest federal, state, and local law enforcement agencies, seeking to discover how they use the polygraph during hiring and what safeguards they have in place to prevent abuse. The results were erratic—and discouraging. A quarter failed to respond at all, and nearly half said they had no responsive documents— meaning they do not track the age, gender, race, or disability status of those undergoing examination.
But the results obtained offer a peek inside an outdated system that continues to influence who gets hired—and who doesn’t—at some of the most important institutions in the United States. Inconsistent and skewed polygraph screening programs are undermining the very places that are designed to uphold the law—a failure that comes with personal costs.
Lie detection has come a surprisingly short way from its inception a century ago. As a graduate student at Harvard in 1915, American psychologist and proto-feminist William Marston noticed that when his wife “got mad or excited” her blood pressure seemed to climb. He theorized that measuring her blood pressure while asking her questions could reveal deception by pinpointing the answers that caused a spike.
With the United States’ entry into World War I, Marston approached various government departments with the idea of developing his system as a tool to trap spies. He eventually secured a position in a medical support unit of the War Department (the precursor to the Department of Defense), where he carried out his initial research, often using women in university sororities as subjects.
After the war, Marston trained his focus on the legal system. In 1921, James Frye, a black man in Washington, DC, was accused of shooting a doctor. Frye confessed the crime to police, then a few days later recanted his confession. Frye’s lawyer brought in Marston to test his client’s honesty.
At the time, Marston’s device was a hack: a basic blood pressure monitor, administered with a medical cuff and stethoscope. After subjecting Frye to an examination, he concluded that his story of innocence was entirely truthful and agreed to testify on his behalf. However, the judge objected to the use of an unknown and unproven tool. An appeals court agreed, writing, “The thing from which [a] deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.” This became known as the Frye standard. Because polygraphs have never convinced the majority of scientists, the Frye standard has excluded them from most courtrooms for almost a century.
The experience only fueled Marston to make his method more sophisticated. He began working with a device, soon dubbed the polygraph, that measured blood pressure, breathing rate, and skin conductance—aka sweatiness. With some electronic and digital upgrades, these are essentially the same devices in operation today. Marston was media-savvy, touting polygraph technology in a public advertising campaign and, ultimately, even in comic books. While working as a consultant to DC Comics in 1940, Marston proposed a female superhero, Wonder Woman. She would be strong and smart, armed with bulletproof bracelets and an unbeatable lie detector—a Lasso of Truth that prevented anyone within its golden orbit from lying.
In reality, Marston’s design was far from perfect. Mainstream psychologists were concerned that the physiological responses the polygraph recorded could be caused by a host of things other than deception; the device might capture unrelated emotions, such as nervousness, arousal, anxiety, or fear. And once you have results, their meaning is open to interpretation. A polygraph only records raw data; it is up to an examiner to interpret the data and draw a conclusion about the subject’s honesty. One examiner might see a blood pressure peak as a sign of deception, another might dismiss it—and it is in those individual judgments that bias can sneak in.
But regardless of a polygraph’s accuracy, some organizations were beginning to find it useful. The polygraph’s scientific aura gave police a tool to intimidate suspects and recruiters a convenient way to shape their workforce. By the middle of the 20th century, polygraphs were being used by government agencies, factories, and banks to screen employees and investigate crimes, with little control or oversight. During the Cold War, federal polygraph tests were used to target left-wingers and homosexuals in government agencies.
Eventually, science began pushing back. In 1965, the US Committee on Government Operations evaluated the scientific evidence for polygraphy and concluded: “There is no lie detector, neither man nor machine. People have been deceived by a myth that a metal box in the hands of an investigator can detect truth or falsehood.” The next year, the American Polygraph Association was formed to promote polygraphy and provide standards for examiners and technologies.
In 1988, after years of intense lobbying by unions, the Employee Polygraph Protection Act prohibited most private companies from using lie detector tests. But the unions did not get a clean sweep: The Act excluded federal, state, and local government employers, along with private companies whose business is moving cash or drugs.
The American Medical Association had come out against pre-employment screening in 1986, and in 1998 the Supreme Court also chipped in, saying that there was simply no scientific consensus that polygraph evidence is reliable. In 2004 the American Psychological Association said “the lie detector might be better called a fear detector,” noting there was virtually no research validating its use in job screening.
In 1999 the Department of Energy asked the National Academies of Science to review the scientific evidence of the validity and reliability of polygraph examinations, particularly as used for screening.
The resulting committee visited governmental polygraph units and reviewed almost a century of scientific papers and data. Its comprehensive report, which took four years to research and write, was damning. “Almost a century of research ... provides little basis for the expectation that a polygraph test could have extremely high accuracy,” wrote its authors. “Polygraph testing yields an unacceptable choice between too many loyal employees falsely judged deceptive and too many threats left undetected. Its accuracy in distinguishing actual or potential violators from innocent test takers is insufficient to justify reliance on its use in employee screening.”
In short, the technology was judged to be pseudoscientific hokum.
It was the polygraph’s tendency to produce false positives that especially worried the Department of Energy. Imagine using a polygraph in an investigation like the one proposed by US senator Rand Paul to identify the author of a damaging anonymous New York Times op-ed earlier this month. If a polygraph is accurate 85 percent of the time, as some data suggests, an investigation of 100 White House senior officials might well identify the guilty individual, but at the cost of falsely accusing 15 others. Shift that accuracy to 65 percent, a figure many critics suggest, and you couldn’t even be certain your culprit would be among the 34 individuals the machine would accuse.
In 2005, the Department of Energy report concluded that “false positives … clearly affect the morale of those for whom such a result is reached. They risk interrupting the careers of valuable contributors to our nation’s defense [and] pose a very serious risk of depriving the United States of the vital services of individuals who may not be easily replaced.”
Christopher Talbot would never become a New Haven police officer. Despite his heartfelt plea, the commissioners voted unanimously to remove him, and dozens of other candidates, from consideration.
Of course, Talbot may in fact have been guilty of a lie or crime for which there was no other proof. But evidence amassed by WIRED suggests an equally likely explanation: that he was the victim of a flawed and unreliable technology that is also vulnerable to examiners’ own personal prejudices.
Data obtained by WIRED showed vast differences in the outcomes of polygraph tests depending on the examiner each candidate faced. Consider another law enforcement agency that uses polygraphs in its employment process: the Washington State Patrol (WSP). Between late October 2011 and the end of April 2017, the WSP conducted 5,746 polygraph tests on potential recruits. This was the largest data set WIRED received, including copious data on both applicants and examiners. While one examiner failed less than 20 percent of candidates, others failed more than half the applicants they screened. And while two examiners disqualified just four people in more than 1,000 applicants for supposedly having sex with animals, one of their colleagues failed more than 10 times as many for bestiality—around one in 20 of all job seekers. The same examiner was also twice as likely as the rest of his peers to fail applicants on the grounds of child pornography.
There were no further hearings for these supposed crimes, and no jury to convince or judge to adjudicate, just scores of otherwise qualified applicants who would now not become Washington state troopers.
“We don’t know which, if any, of the examiners are accurate, but the disparity between them suggests the test is not being used in a way that is at all reliable,” says John Allen, a professor of psychology at the University of Arizona. And tests that are not reliable, Allen says, cannot be valid.
Not only can a failing polygraph test cost you a job, it can also follow you around throughout your career. People who fail a polygraph are usually asked to report that fact if they reapply for law enforcement positions nationwide, and some departments can share polygraph results with other agencies in the same state. “The polygraph’s great flaw is the substantial number of false positives that it gives out, especially when you’re using it for large-scale screenings,” says former CIA director James Woolsey, in a previously unreleased interview from 2009. He believes that polygraphs do not accomplish much more than “seriously damaging a lot of people’s lives by having them fail the polygraph when they haven’t really done anything.”
This is not just a problem in Washington state. Around the US, most police departments use similar test formats and near-identical lists of questions, yet polygraph pass rates vary wildly. According to data supplied to WIRED, the toughest place in the country to take a polygraph could be Houston, whose police department passed just 32 percent of applicants in 2009. More recently, less than half (47 percent) of applicants passed the San Diego Police Department’s polygraph test in 2017.
Slightly more lenient is the Texas Department of Public Safety in Austin, which passed 60 percent in 2016. But if you fail there, you could try again down the road at the Dallas Police Department, where 77 percent of test-takers passed last year. And if the thought of all those wires and dials really gets you nervous, head to Baltimore, where more than 91 percent of applicants aced the polygraph in 2017. Despite similar tests and presumably similar applicants (especially in Texas), the departments' pass rates are wildly different—and these rates have varied little over multiple recent years.
But while polygraph examinations can be a lottery, history seems to show that the house can sometimes tip the odds.
Forty years ago, Harold Moon applied for a position as a correctional officer in Cook County, Illinois. After taking a polygraph test, Moon, who was black, was informed that he had failed and was rejected. Moon then brought a class action suit alleging discrimination in violation of the 1964 Civil Rights Act. His suit included analysis that there was only a one in 1,000 chance of the high polygraph failure rate among black applicants in Cook County between 1976 and 1978 being random. The Congressional Record in 1987 noted that Moon’s case was quietly settled, including an agreement with Cook County to eliminate the polygraph requirement.
That agreement would probably come as news to Donna Bibbs and two other African Americans who filed their own Civil Rights Act lawsuit against Cook County and its Sheriff’s Department in 2010. Bibbs and her fellow plaintiffs alleged that they were rejected for employment because of confessions given during their polygraph examinations that were never actually made.
“The Sheriff has not adopted any procedure to allow applicants to dispute the correctness of reports of admissions on the polygraph examination,” read their complaint. “A consequence of [this] is to vest the polygraph examiner with the final authority to reject applicants by making false reports of admissions.”
This case never made it to court either; the parties eventually reached a settlement in 2016. There is no indication that Cook County has since altered any of its policies, and, in fact, the Sheriff Department’s legal department told WIRED that it does not retain polygraph records in an aggregate format, rendering it unable to track systematic racial bias.
From WIRED’s public records requests, it appears that few jurisdictions retain these records, making it nearly impossible to systematically identify bias in their programs. That comes as no surprise to William Iacono, professor of psychology, psychiatry, neuroscience, and law at the University of Minnesota. “[Demographic data] sounds like something these organizations don’t want to have,” he says. “Because if they have it, and someone asks for it, then it might reveal something that they’re not comfortable with. The examiner doesn’t really use an algorithm to figure out if people are employment worthy. The examiner’s decision is probably based primarily on the human interaction that the two people have.”
In a survey of Virginia’s state licensed polygraphers carried out by University of Virginia researcher Vera Wilde in 2011, roughly 20 percent of respondents said they thought certain groups (for example, black people) tended to fail polygraphs more than others. In a US Senate hearing in 1987, the attorney general for New York said, “The [polygraph] operator’s prejudices, moods and feelings can strongly influence and even determine the outcome of the test. For example, we have received complaints about a polygraph operator who consistently fails a much higher percentage of black subjects than white subjects.”
A study carried out for the Department of Defense’s Polygraph Institute in 1990 showed that innocent black polygraph examinees were more likely to suffer false positives than innocent whites, under mock crime conditions. The National Academy of Sciences report in 2003 worried about possible race, age, and gender biases, but noted that little research had been done in the area. “We know that there’s a potential effect of gender [and] race, in terms of [the] mix of polygrapher and subject,” said NAS committee chairman Stephen Fienberg in 2009. “We know that context matters. And we know that there can be systematic biases.”
In 2007, a federal court observed that black applicants to the Arkansas State Police one year failed polygraphs at twice the rate of white applicants, although the numbers were too small to draw firm conclusions.
Dozens of equal opportunity complaints have been made against the FBI’s polygraph screening unit, accusing examiners of racial and other biases. Many of the complaints, released to Wilde under Freedom of Information laws, reveal applicants’ frustrations with an opaque and seemingly hostile process.
In 2008, one failed applicant wrote: “Black females are subjected to an entirely different level of scrutiny. I was given a polygraph test in Memphis and told that I failed, which was given by a male white. I requested a retake and was told that I passed the second polygraph test taken in Nashville, TN., which was given by a male black.” The FBI recorded her as saying its hiring criteria were “preset for hiring white males.” Both her application and her subsequent complaint were denied.
While undergoing a polygraph examination for a position at an FBI field office in New Haven in 2010, a black man was told that his recollection of using marijuana only a few times in high school was showing as deceptive, and that he should change his answer. Later, he wrote: “I was convinced that [the examiner] may have made an assumption, based on a stereotype about African Americans and drug use, and used that stereotype to profile me. I also realized that what [he] was asking of me would reflect negatively either way—if I didn’t change my answer I was being deceptive, and if I did change my answer I was lying on my application.”
This catch-22 grievance was investigated by the Department of Justice’s Complaint Adjudication Office in 2012. That office noted that the FBI had another polygraph examiner review the case blind, with “no information concerning complainant’s race.” However, the FBI’s definition of a blind review demands some scrutiny. The second examiner wrote that “the only personal information available to him when conducting the review was complainant’s name, date of birth, social security number, gender, height, weight, and address.” The controversy around so-called redlining has shown repeatedly that race and zip code (and even names) are closely linked. The man’s complaint was ultimately dismissed, as were all the other complaints obtained by Wilde.
The FBI rejected multiple requests from WIRED under the Freedom of Information Act for the demographics of applicants failing its polygraph screening tests, citing exclusions for law enforcement and national security data. However, the agency accidentally included relevant (but incomplete) data in a response to Wilde in 2012, not published until now.
The New Haven discrimination investigation included a memo stating the racial backgrounds of 130 FBI applicants who had failed preemployment polygraph tests between October 2008 and June 2010. (An additional 2,130 applicants who failed the polygraph were listed as “race unknown.”) While 12 percent of FBI staff are black, 19 percent of those failing its polygraph tests were black. Asians, Hispanics, Native Americans, and Pacific Islanders were also overrepresented in those failing the polygraph. And although 75 percent of FBI workers are white, they made up just 57 percent of applicants failing the polygraph tests.
New data collected by WIRED show that local police departments fare little better. The Metropolitan Nashville Police Department uses a computerized voice stress analyzer (CVSA) in place of a polygraph. This is a machine that supposedly detects deception by analyzing the low frequency audio information from answered questions about sensitive topics—some systems purport to detect “micro tremors” in deceptive answers. The technology is regarded with as much skepticism in the scientific community as polygraphs.
Data supplied to WIRED by the Metro Nashville Police Department show that black applicants are selected at only about half the rate of white applicants, and that Hispanic and Native American officers are also significantly under-selected. Metro Nashville also selects younger candidates (up to age 39) at nearly twice the rate of older ones (40 or older). The department says it has no record of anyone making an age, gender, or race-related complaint about the CVSA test, and that no applicant is ever disqualified based on a CVSA result alone.
Although a voice stress analyzer test is only one part of Metro Nashville’s hiring process, there is some evidence that lie detector screening contributes more directly to lopsided hiring practices elsewhere. The Baltimore Police Department might have a relatively lenient polygraph screening system, passing the vast majority of those applying, but black applicants from 2013 through 2017 still failed their polygraph tests at higher rates than their white counterparts. In 2016 and 2017, they failed more than twice as often.
Discrimination can work the other way too, if departments are giving preferred candidates a second shot at passing a test. In a 2014 internal survey of the San Diego Police Department’s polygraph unit, supplied to WIRED, one police officer noted: “I feel the examiners do a good job … They always offer to re-test if we want to.” This calls into question whether all applicants are treated equally, and suggests that even some police officers suspect the test is not always accurate.
While the 2003 National Academy of Science report removed the last vestiges of polygraphy’s scientific credibility, researchers continue to track the technology’s real-world use. A 2017 study at Walden University in Minneapolis found no relationship between preemployment polygraph exams and officers’ propensity for future misconduct—a purported justification for administering polygraphs—nor any differences in attitude toward misconduct between officers who had or had not undergone such testing.
“The research we’ve done shows that there’s no higher level of misconduct among police departments that don’t give polygraphs to applicants [than among] ones that do,” says Daryl Turner, president of the Oregon Coalition of Police and Sheriffs, an association of law enforcement professionals that campaigned against a bill last year to introduce preemployment polygraph screening in the state. “We also feel [the polygraph test] is not a fair assessment of a person’s truthfulness or integrity.”
That is not a view shared by the American Polygraph Association, which certifies polygraph schools across the country. The majority of law enforcement agencies using polygraphy require examiners to be graduates of an association’s polygraphy course, which costs around $6,000 and can take 10 weeks to complete.
The Washington State Patrol says that all of its examiners are APA certified, carry out polygraph tests consistently, and check results with colleagues. Despite that, data supplied to WIRED shows that the WSP hires black men at a lower rate than white men, and is more likely to fail older candidates during its polygraph screening.
WSP lieutenant John Matagi could not offer a good reason why its examiners failed applicants or uncovered crimes at different rates, except to say: “They’re humans making human decisions [and] as each polygraph examiner gets better at their skill, they will have different results.” He also brushes off concerns that older candidates fail more often. “One of the things we speculated is that people who have been alive longer have more opportunity to engage in activity that is disqualifying,” he says.
Other departments appear more concerned about possible inequities. The Dallas Police Department supplied WIRED with data on the gender and race of its applicants and their relative success in polygraph tests. It also compared each group to the majority demographic of applicants. (As in every department that gave data to WIRED, this was white males.) Dallas reported more equitable hiring outcomes, and less variation between different groups, than other departments that responded: Both genders and all racial groups passed at similar rates.
So if the polygraph is so unreliable and prone to bias, why does law enforcement continue to use it? WSP’s Matheson says that much of the value in polygraph testing comes during the pre-polygraph interview, where “it is not uncommon for us to learn information that disqualifies the candidate. That’s a big part of the value of what we hope to gain from the entire process.”
In other words, the mere specter of being subjected to a lie-detector test can induce applicants to confess information they might have otherwise withheld.
Between 2010 and 2017, the Phoenix Police Department told WIRED that it conducted 3,711 polygraph tests while recruiting sworn officers, civilian staff, interns, and volunteers. On 96 occasions, applicants admitted to crimes during or after their test, including two confessions of extortion—and four of murder. Although the polygraph cannot reliably detect truth or falsehood itself, its cultural reputation for omniscience can be used by an artful examiner to elicit confessions from nervous or suggestible subjects.
“The one thing that lie detection appears to be good for is tricking naïve people into thinking that the person who’s examining them knows more about what’s in their mind than they actually ever could,” says Jay Stanley of the American Civil Liberties Union’s Speech, Privacy, and Technology Project. “It’s an intimidation device.”
The polygraph industry does not always get its way. The ACLU and the Oregon Coalition of Police and Sheriffs succeeded in fighting off the attempt to legalize polygraph screening tests in Oregon last year, and evidence obtained using a polygraph remains inadmissible in most legal settings.
Even the New Haven Police Department, which continues to use the polygraph for screening recruits, has proposed shifting their standards around the test. Earlier this year, the New Haven mayor’s Police and Community Task Force noted that minority officers are underrepresented in the department and laid part of the blame for that with the polygraph screening process. “NHPD needs to create a policy prohibiting contact between the psychologist and recruitment staff and the person administering the polygraph test,” it wrote in a report.
According to the best available science, polygraph tests are no more reliable at extracting the truth than Wonder Woman’s magic lasso. But by the time a new installment of the super hero’s story is released, in November 2019, millions more polygraphs will have been administered across the nation.
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