The nation just watched Judge Brett Kavanaugh and Dr. Christine Blasey Ford testify about Dr. Ford’s allegations that Judge Kavanaugh sexually assaulted her 36 years ago. Part of Blasey Ford’s supporting evidence for her claim is that she took and passed a polygraph test on August 7th of this year. How does it compare with other polygraphs, and what can it tell us?
Not a Science
There is a reason polygraphs are not admissible in court. They are unreliable and subjective. Their effectiveness depends on a number of factors, including the overall state of mind of the test subject, the identity and background of the interviewer, and the types of questions. The experience of the interviewer and the interviewer’s understanding of the test subject play an outsized role in obtaining and interpreting the results.
In the later years of the Reagan administration, Secretary of State George Schultz threatened to resign rather than take a polygraph. He rejected congressional attempts to require them at the State Department. His objection, he said in congressional testimony, was that they were not reliable. “If they were reliable,” Schultz said to somewhat nervous chuckles, “the wife of every member of Congress would have one.” That ended that policy proposal.
It is inaccurate to call polygraphs “lie detectors.” They don’t detect lies, they detect stress while telling a lie. If a person feels no stress while telling a lie, the machine will not detect it.
The polygraph looks scientific, because it measures bodily (galvanic) responses while the test subject is talking. The machine is hooked up to various points on the body, to measure heart rate, blood pressure, perspiration, and breathing. The theory is that if a subject believes you can tell she is lying, she will feel stress at the thought of being caught.
Interpreting the test is also subjective. According to William Iacono, a polygraph expert quoted in The Washington Post, senior executives in intelligence agencies almost never fail polygraphs, but 30 to 40 percent of new applicants do. That is not just because the executives lead totally exemplary lives, it’s also because no polygraphist wants to accuse the CIA Director or Deputy of lying.
Errors: From False Positives to Sociopaths
Most people feel stress when they fear that a lie may be exposed. Ethical people feel stress when they lie. A large minority of people feel stress when they know someone thinks they are lying, even if they are telling the truth. Those people generate false positives. Unfortunately for them, they can even get trapped in a cycle where they anticipate the question, and generate an increased stress response each time they answer it.
Polygraph tests are manna from Heaven for subjects with certain psychological disorders. They have nearly no effect on sociopaths, psychopaths, or people with borderline personality disorder. Anyone who is not overly burdened with a conscience or empathy has no trouble lying, and therefore no trouble passing a lie detector. But they also are easy to pass when the test subject feels no connection with or respect for the test administrator.
The Soviet Informant
Old Sovietologists remember a case from the 1970s that illustrates the importance of the polygraph administrator, or polygraphist. The CIA had recruited a mole within the Soviet military, who was passing them sensitive information. Each time the U.S. government conducted an operation on the basis of the information; however, it proved faulty.
Supervisors in both Washington and at the relevant diplomatic mission suspected that the mole was a double agent, purposely passing us false information. He was given several polygraphs, and passed them all quite easily. They even brought him to Washington to have him tested with their best equipment and by their best polygraphists. He passed them all easily, but his information still seemed suspect.
Washington requested a background and psychological workup on the agent. He was from one of the Central Asian republics, and was Muslim. Washington found a Muslim polygraph administrator, and sent him overseas to interview the agent. He introduced himself to the subject, they discussed their mutual faith and background, and then he administered the polygraph.
The Soviet agent failed the polygraph spectacularly. He had no trouble lying to Americans who also were infidels; they were unworthy of his respect on both counts. But he felt stress when lying to his coreligionist, to whom he felt some level of duty.
It’s Not Just the Polygraph, It’s the Questions and the Administrator
The real key to an effective polygraph is understanding the background and mindset of the subject. An effective polygraphist will administer a drug screen and a psychological screening, in addition to obtaining a comprehensive biographical file. Dr. Ford’s polygraphist, Jeremiah Hanafin, told CBS News that he interviewed her at length before the test. This explains her rather cryptic remark that the test took a long time and seemed to cover her life history.
It also explains the apparent contradiction between that statement and the test results released by her attorneys, which showed only two short, very general questions. She was referring to the general biographical interview, and the test results showed only the two actual questions that were administered in her polygraph. During the biographical interview, Hanafin would have been monitoring her responses to determine a baseline against which to measure her responses.
As a side note, Dr. Ford said she cried a lot during that interview. It is difficult to see how Hanafin could calculate an accurate baseline measurement while she was crying. The effect on her perspiration, blood pressure, heart rate and breathing would reflect stress, just as guilt or fear about lying does.
What Hanafin did not do, according to any public comments about the process, was administer either a drug screen or a psychological profile. Many medications will dampen the stress responses picked up by the polygraph. Xanax and other anxiety medications, and blood pressure medications, are especially effective in masking stress responses.
The Psychological Screen
Anyone truly interested in obtaining a reliable result would not pick the polygrapher without first conducting a psychological screen. That would have suggested what type of polygrapher to recruit. It also would have informed the polygrapher what types of questions to ask to provoke stress responses and to induce baseline “truth-telling” responses.
All we know for sure about Dr. Ford’s general ideological background is that she went to one of the women’s marches in 2017. Although it was billed as a march for science, it was an overtly political, anti-Trump event. We also know that she considers herself a survivor of a sexual assault; that forms a significant part of her identity.
Assume for a moment that Ford is generally Leftist in her ideology, and that she feels a closer kinship with Leftist or liberal women than she does with, say, white males who are retired law enforcement officers, like Jeremiah Hanafin. Would her test responses have been different if her polygrapher had been female?
What if Ford had been interviewed by a Leftist woman who shared her political feelings? What if it had been a woman who had experienced sexual harassment or a sexual assault, or survived an actual rape? We would have far more confidence in the reliability of the results.
Like computer programming, polygraph output is only as reliable as the data entered. Unfortunately, this polygraph was paid for by her attorneys, and seems to have been designed to ensure a negative response. It is quite useful as a public relations tool, but is unreliable as a measure of the truth.
