Other Wars of the DoD articles can be found here.

How good are lie detector tests at achieving their goal of detecting lies?

There is an extraordinary amount of debate on this topic that goes back a full century:

A precursor to the polygraph was first used in 1921 by psychologist, lawyer and inventor William Marston, who later created the comic superhero Wonder Woman. A man named James Frye had been accused of murdering a prominent physician in Washington, D.C. He had confessed to the crime and then recanted his confession. Marston used a blood pressure cuff on Frye while asking him questions and measuring his physiological reactions. He claimed his test showed Frye to be innocent, but a judge in the case refused to admit the results as evidence, citing a lack of general acceptance by the scientific community. The ruling established what came to be known as the Frye standard, which governs expert witness testimony in many states, including Minnesota, to this day.

Before we move forward, let's be clear: there is no one type of lie detector test, but when we talk about lie detector tests, we generally refer to the traditional polygraph test.

How Polygraph Tests Work

Technically, there's more than one answer. I'll explain…

A polygraph machine is not unlike what kids have to strap themselves into to play video games these days. Try not to think about it.

Most polygraph machines measure

Breath rate.
Pulse.
Blood pressure.
Perspiration.
Willingness to participate (binary).

What it doesn't do is determine whether or not the subject is lying. Only Big Tech and Politifact are endowed with such superpowers. (Just kidding.)

A polygraph operator uses some simple questions to calibrate feedback. Different people have different physiological responses to being asked questions. Some get stressed more than others, and some begin rhetorically asking about the definition of "is".

Some others hold a press conference.

(Just kidding.)

After the test is calibrated, the polygraph operator judges as best as possible whether the data from the measured metrics fits with the calibrated controls.

Polygraph Tests: Admissible in Court?

In an interview or two over the past year, I mentioned that polygraph tests are not admissible in court. Mea culpa. When I "learned" that "fact", I must have been in a state where they were not admissible. But I've since learned that they are admissible in some states, but not in others. From lawinfo.com:

Those who think polygraph evidence should be used in court say that the tests are reliable most of the time and, therefore, useful information. However, many experts disagree with the assumption that lie detector tests are reliable in most situations. Accordingly, in leaving the decision up to individual jurisdictions, the Supreme Court commented that there is no reliable scientific evidence about the accuracy of lie detector tests. Still, the Supreme Court has not forbidden it outright.

Estimates differ, but the accuracy of a polygraph test (per operator) at detecting lies seems to be around 87%. But such a number is not set in stone! It may vary greatly among different people.

There is also a major problem leaping for percentage accuracy to meaningful results, however. An educated and skilled individual can push the accuracy very close to a fair coin flip (50/50). This is because studious individuals learned how to hack that game, and eventually experts like Doug Williams broke down and just gave the game away, completely.

Perhaps in some courtrooms, the jury is given the opportunity to decide, based on additional evidence about the person taking the test, whether the test is likely to be reliable.

Whether or not polygraph tests fairly work as lie detector tests, some investigators may find them helpful for determining who is and is not nervous about some important topics. This might help detectives track down better information aside from the test results.

Now, let's wade into the deep end of the pool…military intelligence.

The People Who Fool the Machines

While we have talked about people trained to game polygraph tests, most people don't go so far as to train themselves into the appropriate meditative state. Even so, there are still problems. One of the issues with polygraph tests is that there is a small subset of people whose polygraph results are not observably dependent on whether they're lying or telling the truth. From Psychology Today,

In February of 1994, the FBI arrested Aldrich Ames, who had been a CIA employee for 31 years. Ames was arrested and charged with espionage. He was a Russian spy. For nine years, he had been passing secrets to the Russians in exchange for over $1.3 million. His spying activities had compromised dozens of CIA and FBI operations. Worse yet, his treacherous crimes had led to the deaths of several CIA spies and the imprisonment of many more.
During the time that Aldrich Ames was operating as a Russian spy, the CIA had twice given him a lie detector test. Despite having no special training in how to defeat a lie detector test, Aldrich passed both times.

A few weeks ago I shared a several hour car ride with a Signals Intelligence (SigInt) officer in the U.S. military. She explained that everyone serving in SigInt submits to polygraph testing annually. It was the second time we'd had a conversation about it over the past several years. The first time she complained that she was weirdly growled out by the polygraph operator over the results, which surprised her. She laughed it off, but it was enough to make her ask about the test the next time around. During her more recent test, she asked the operator about the purpose of the test and was told that people who showed no response were removed from military intelligence.

Tell Me Another Fairy Tale

Upon hearing this story about people Ames-ing the polygraph, I declared shenanigans, and my passenger laughed and said something like, "Yeah, that's kind of what I thought, too." What I'd said specifically is that those "removed" over such a test were likely identified as cool psychopaths, and simply reassigned and retrained for work that requires their rare attributes.

Thinking from the point-of-view of the top of the opaque hierarchy that is military intelligence (which might as well be all of U.S. intelligence now that the DNI runs the whole show), can you imagine just tossing aside an asset like that?

I certainly can't.

Now, exercise your imagination and ask yourself how you would repurpose such an asset. The only limit is your creativity.

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