Have polygraphs changed much since Sgt. Friday ran his Dragnet?

Have polygraphs changed much since Sgt. Friday ran his Dragnet?

I’ve seen a couple demonstrated on TV along with stories about the missing congressman’s aide, and they look like the same chest and finger wires, connected to the metal briefcase.

Surely there must be digital equivalents by now, with more sophisticated readouts, and using many more kinds of probes.

Or not?

Anybody actually taken a test?

Don’t have any first-hand experience, but from I’ve read and heard, I wouldn’t be too comfortable if my fate were to rest on a polygraph result. It sounds like you can pretty much get any result you are looking for depending on how the exam is administered. I also believe that the machine is essentially unchanged from its early models.

here is a link from the Skeptical Inquirer that is pretty …skeptical (you were expecting something else?).
They also apparently have an article on polygraphs in their new issue, which isn’t online yet.

I’ve taken one twice. Once when I was in Military Police school, they grabbed about 20 of us one day and bussed us over to the CID school (CID is the Army equivalent of the FBI). We were used as test subjects for the school’s polygraph course. What the hell, it got me out of rock painting detail.* The second occasion was when I applied for a job as a sheriff’s deputy when I was in college. I decided to go back on active duty, so I turned down the job anyway.
*[sub]In basic training, there is a joke that there are only three rules a private needs to know:

  1. If it moves, salute it.
  2. If it doesn’t move, pick it up.
  3. If you can’t pick it up, paint it.[/sub]

Oops, I forgot to answer the OP. Both tests were in 1987, but the machines looked just like the ones you describe. I don’t think there’s been a lot of change in the equipment over the years.

There’s been very little change over the years, though there are people working on better versions. Discover magazine had a good article on the subject a month or two ago. Lemme see if I can find a link…

Found it. No direct link, but go to discover.com, go to the July 2001 issue, and click on the “Works in Progress” link.

Found it! Here’s the link:

** http://discover.com/july_01/featworks.html **

That was exactly what I’d hoped to turn up.
One of the things Marilyn Vos Savant has repeatedly said was her most-awaited invention was a good lie detector. If nothing else, it would stop a lot of the political/sexual scandals from brewing so long before they burst.

I liked this quote from that article -

I think that this means a criminal could easily defeat the polygraph if he could practice with one. Surely any crook with a little dough could find someone to help him run practice tests while he watched.

This then becomes a form of biofeedback. You can train yourself to pick another emotion to substitute for the true one. I know you can force a “lie” by simple means like biting your cheek - pain looks like fear, which is interpreted as fear of exposure. There must be other emotions you can practice, like pride or triumph to change a lie into a personal “truth”.

I had been accused by a coworker of making anonymous sexy phone calls to her house late at night. (The reason she thought it was me was she kept asking the guy, Is this Joe?..I bet it’s Bob…etc. and on the fifth guess the guy “confessed” to being me.)

Anyway, I instantly asked for a company lie detector test to stop her from spreading rumors. (The company mainly used them for getting top monetary access clearances.)

I passed except for one part, my address!

When the tester asked, I had to decide whether to give my PO Box or street address. I only hesitated a second, and decided on the P.O. Box, since it was on the ID I’d already handed him, but “indecision” was recorded as “lying”. A glance at my driver’s license proved I hadn’t been lying, so the operator said he’d “overlook” that one as not significant.

I won my point and she backed down, but I suddenly realized how dangerous it had been for me to take the test. What if I had hesitated about something that couldn’t be proven? I’d have been fired and maybe even barred from getting a good reference.

I own a book that, among other things, gives a technique for beating lie detector tests. I don’t feel like finding the book right now, but I remember the jist of the technique. Those of you that have taken lie detector tests can tell me if this is on the ball. According to the book:

-There are four types of questions asked during polygraphs: general knowledge questions, irrelevant questions, control questions, and central questions.

-General knowledge questions are things like “Who is the president of the U.S.?” or “What is your address?” These are questions that everyone knows the answer to, and are used to establish how you behave when you’re being truthful.

-Irrelevant questions are, well, irrelevant. “How do you feel today?” “What is your favorite color?” They don’t really care about your answer, and are just trying to break things up a little.

-Control questions are where things really start to get f—ed up. They will ask something like: “Have you ever stolen anything in your entire life?” If you admit to something, they will re-word the question to exclude that incident, and ask again until you say “No.” The thing is: they will assume that you’re lying. What they’re tying to do is to get an idea of how you behave when they know that you’re lying, but their methods of doing this are obviously pretty far from foolproof. In fact, I doubt that they can even see ‘foolproof’ from where they are.

-Central questions are the questions that they’re REALLY interested in, like “Did you embezzle $10,000 from the company?” or “Were you having kinky sex with that intern, Mr. Condit?” They will interpret your answers for the central questions based on your responses to the control and general knowledge questions.

-The trick to beating lie detector tests (supposedly) is to pick out the control questions and make a big deal when answering them, so you appear to be really, really nervous at those points. Consequently, when they ask a central question and you lie for real, you won’t seems as nervous as when you were ‘known’ to be lying. The book suggested hiding a pebble in your shoe and pushing your foot down on it when you’re asked a control question.

-As I said above, this is all from a book I read. I have no idea if this actually works or is even remotely like a real polygraph test, so YMMV.