Criminals lie, just like the rest of us. And as a whole, humans are terrible at detecting when we’re being lied to. According to a meta-analysis of “deception judgments,” we only recognize a deliberate falsehood about 55 percent of the time. It’s better than a coin flip, but not by much.
As such, there’s obvious appeal to a lie detector test: a technology that goes beyond the naked eye in measuring honesty. And in the early 20th century, Dr. James Mackenzie invented the polygraph “lie detector” test, based the premise that through the measuring of physiological response we would be better able to pick up on falsehoods.
But does it work?
A&E True Crime spoke with George Olivo, a retired FBI special agent and senior polygraph examiner, about the test’s reliability.
Olivo appears in the upcoming documentary Casey Anthony’s Parents: The Lie Detector Test which premieres on Thursday, January 4 at 9/8c on A&E. The documentary will be available to stream in the A&E app the next day.
You spent 14 years in the FBI before you ended up working as a polygrapher. Can you explain how you ended up where you did?
I started in 1998. I was working in violent crimes—doing bank robbery investigations, things like that. But when 9/11 happened, in 2001, they sucked a lot of agents out of criminal work and put them into intelligence and terrorism.
So in 2001, I started working on a counterintelligence squad. We were spy catching. You can think of the CIA and the FBI as being akin to the offense and the defense. The CIA goes out and spies. The FBI stays at home and tries to prevent other countries from doing that to us.
From there, in 2011, I went into polygraph work.
I love to interview people. And FBI investigations are very long. They can be two-to-four year investigations. And you don’t interview the main subjects until the end of the investigation. Usually it’s months of collecting information.
But the polygraph goes hand-in-hand with interviewing people every day.
[Stream Casey Anthony’s Parents: The Lie Detector Test in the A&E app.]
Can you explain how the test works?
You can think of it as being similar to a tape recorder: A tape recorder doesn’t add or subtract information. It records in real time, every word. Polygraph works the same way. It doesn’t edit or summarize…it just records everything in real time. But it doesn’t record sound. It records physiology, what the body is saying: heart rate, sweat gland activity.
And we record physiology because we say physiology always tells the truth.
The body never lies because it’s based on the autonomic nervous system.
The fight-or-flight response happens automatically whenever you perceive a threat. And it also occurs when you lie. It’s the perception of jeopardy—of getting caught in the lie—that causes the response.
If you tell a lie, and you’re in a polygraph chair, you think, what’s going to happen to me if I get caught in that lie? That risk of exposure…causes a fight-or-flight response.
Is there a strategic art and science to asking questions during a polygraph? Does what and how you ask questions matter?
Everything matters when it comes to test questions for legitimate polygraphs. Test question construction, explanation and presentation are all critical aspects of a legitimate polygraph exam.
The sequence in which the questions are presented is also very important, which is why only validated test formats should be used to ensure fairness and accuracy. Relevant questions must be neutral, single-issue and fact-based.
An example of a poorly worded question in a rape case is ‘Did you rape Jane Smith?’ A better [version is] ‘Did you ever have non-consensual sex with that woman?’
Repetition is also critical to establish a clear pattern of truthfulness or deception, based on objective diagnostic features. That is why all questions are asked multiple times, verbatim, with short breaks in between.
Feelings, intentions or emotions are never appropriate relevant polygraph questions because they are not factual, black and white issues.
All questions must be answered ‘yes/no’ and thoroughly explained in advance to avoid confusion. In other words, a legitimate polygraph exam is black and white with no surprises.
Can you explain a bit about how the machine differentiates, technically speaking, between a nervous result and a deceptive result?
It does not. That is why [how questions are asked] is so important. To produce fair and accurate results, a polygraph examiner must minimize contaminants, like nervousness [and] confusion, isolate the relevant issues and only use validated test formats.
The polygraph simply records physiological changes in response to questions posed during a structured exchange between the examiner and examinee.
It is a scientific fact that the body reacts in certain ways to stressful stimuli. For most people, the immediate threat of getting caught in a serious lie is a stressful stimulus. Most truthful people will habituate to relevant questions over time, because they know that they are telling the truth. They tend to become more at ease, knowing that the truth is on their side.
By contrast, most deceptive people do not habituate over time. The guilty often produce progressively stronger physiological reactions due to the increased perception of jeopardy of getting caught in a serious lie.
It seems there’s a lot of dubiousness about the test’s reliability.
People say it’s no better than a coin toss. That it’s just a prop. Those are misconceptions. There have been 30 controlled studies done on validated formats of the polygraph test by the National Academy of Science.
If it’s done correctly, it’s pretty good. Nothing’s perfect; nothing’s 100 percent.
But it’s a good tool when it’s used properly—as long as we put it in perspective. It shouldn’t stand alone to confirm truth or try to find deception.
Are polygraph results admissible in court?
There are some states that allow the polygraph in court, like New Mexico. But most states do not—or at least not in front of a jury.
Do you agree with their inadmissibility?
[In a ruling that allowed states to ban polygraph evidence,] the Supreme Court says the jury should be the final arbiters of truth, and I agree with that.
If the test results aren’t admissible in court, then is the polygraph test itself anything more than an interrogator’s prop?
Of course. I can’t tell you how many times I’ve had an agent bring me a suspect or person of interest. We’re not sure if he’s involved in a bank robbery or this or that, and then he’ll pass the polygraph and so we’ll look somewhere else.
You mentioned that the fight-or-flight response is triggered automatically whenever we perceive a threat, or when we’re lying. How can the test, or its administrator, parse the difference? Don’t people sometimes fail the test because they’re stressed by the process itself?
Not every stressful reaction is a deception indicator. You might be afraid of being blamed for something you didn’t do.
And so you [as the polygraph examiner,] do your very best as an examiner to make the person feel comfortable, but the polygraph in its nature is an accusatory process. It just feels that way.
Someone could be overly nervous. Nervousness should not affect the results of the test, but they do sometimes.
If someone is truly innocent, the test should be inconclusive. They shouldn’t fail, if everything goes like it’s supposed to do. In that case we’d retest them another day, and then they’re usually better.
Is there ever a situation where you think an innocent person should nonetheless stay away from a polygraph test?
Yes. If the person doing the polygraph examination is not qualified to do it.
It can’t be stressed enough that what you see on TV or in the movies—that’s not the real polygraph. The whole protocol that’s used is different. The pre-test interview before the test is usually 45 minutes to an hour. You talk to the person, get their side of the story, construct questions in a way that’s fair to that person. We don’t use ‘gotcha’ questions; every question is scoped.
Is that really the only time? If you were hooked up to a polygraph right now, would the results say you were telling the truth?
That would depend on who was running the examination.
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