Tuesday, June 20, 2006

Liar, liar, pants on fire. OK, maybe not

Did you ever play cards with Aldrich Ames? Yes? Why is your heart racing? Why is my heart racing--The Washington Post has an interesting if somewhat incomplete story on the confusion over polygraph tests in the intelligence community. The National Security Agency doesn’t trust the polygraphers at the CIA, the Pentagon doesn’t trust the FBI’s, and the courts don’t trust any of them. The story, by Shankar Vedantam depicts several people caught in the confusion and distrust. The story mentions that master spy Aldrich Ames fooled CIA polygraphs three times. He is hardly the first or last person to fool the machines or their operators.

The story doesn't mention that polygraphs reached the status of religious belief in the intelligence community years ago and challenging them can be dangerous to your peace. See below. The operators essentially are their own cult.

Missing most of all in the story is that polygraphs are crap science. They do not measure truthfulness; they measure anxiety. They are not permitted as evidence in court for that reason and the courts are right. With the exception of Israel (and they may no longer use them either), no intelligence or law enforcement agency in the world uses them or gives them any credibility. They can not only be fooled--and apparently are regularly--but produce false positives at an alarming rate. A false positive means they (or more likely the operators) say someone is lying when they are not. Exact figures are classified (now I wonder why that is) but according the best estimates I was able to reach for a story I did several years ago, it runs about 15%. The article linked to above from Wikipedia, says 10%. That means that people are accused of lying 10-15% of the time when in fact they are being truthful .

Much of the efficacy is determined by factors other than technology. The nastier the polygraph operator is the better the test; intimidation is the juice polygraphs run on. More important, the more convinced you are that the machines work, the better they work, although that does nothing about the false positive problem. On the other hand, if you believe something is true even if it is not, you will fool the machine because you are fooling yourself. Again, it measure anxiety not truthfulness. In some cases, people can be taught to fool the machines, and it is not difficult, experts say, to guarantee an ambigous result. There are even websites that advertise ways of beating the machines. I don't know if those sites actually offer anything useful, but the machines are stupid things to hang national security on.

Even critics of polygraphs point out they are not entirely useless. If you have a small store and someone is raking off profits in the cash register, polygraphs probably can find the culprit because they are honing in on a specific incident among a small number of people and they are all scared to death. If, on the other hand, you use it the way the CIA, FBI, NSA and all the other places do--general screening--you are essentially running a scam. The operators will do every thing they can to convince you this is science, this works, and if you lie to them they will nab your ass. It isn't and it doesn't but they may nab your ass anyhow, perhaps even falsely. If you walk in convinced the tests are crap, you will get a negative or contradictory result or get caught in the 10-15%. Intimidation by the operators is key. One subject in the Post story had an argument with a polygraph operator over the bra size of a teenager he did not abuse.

The Post quotes someone as saying that analyzing polygraphs is more art than science. Actually it is not science at all and art is in the eyes of the beholder. There is no published scientific study supporting polygraphs.

By the way, the piece I did on polygraphs was for a major science magazine which, because of outside pressure on the editor, did not print the article. She is deceased now and refused to tell me what happened to the story before she died, but the pressure was clear and unambiguous. I never forgave her. I must add that the defenders of polygraphs were the most aggressively offensive people I’ve met in almost 40 years of journalism. My opinion above is not unbiased.

No comments: