They tested the wrong guy

Fortunately, I found out about the "Beat the Lie Detector" secondary story in the most recent episode of MythBusters before I watched it. So I knew to fast-forward through the lie detector story and just watch the other one.

This was entirely for the sake of my health. There's no way I could watch someone claiming that polygraphs are "80% to about 99% accurate", and then see a screen shot of software saying "Probability of Deception is Greater Than .99", without dangerously elevating my own metabolic markers.

(But yes, I've skimmed through the lie detector story now, just to make sure the complaints are valid. They are.)

The icing on the cake is the fact that the person making the "80 to 99%" claim, and later administering the polygraph tests, was "Doctor" Michael Martin. Who, apparently, bought his doctorate from a diploma mill.

You certainly don't need university qualifications to be knowledgeable about a subject, but fake degrees are anti-qualifications. Nobody who bought a diploma to make themselves look qualified in an area should be believed about anything, until they say they're sorry and take the unearned honorifics off their business card.

In reality, it is arguable that the polygraph is not entirely useless. (This may set some sort of record for damning with faint praise.)

The polygraph looks especially good if you, unfairly, count the cases in which it's used merely as an intimidation device to trick a guilty person into confessing. Wen Ho Lee, for instance, passed his polygraph test with flying colours - but that was no problem for the Feds, who just said he'd failed. It's like police interrogators telling a suspect that their buddy has already confessed, when no such thing has actually happened.

Contrary to not-a-real-doctor Michael Martin's statement, the polygraph's history is one big losing streak. Nobody's ever actually been able to demonstrate, in proper controlled tests, that the darn thing is actually worth using. Not that many governments or corporations seem to listen when the National Academies of Science tell them as much.

The NAS actually concluded that, although the polygraph is the best lie-detection device created so far, it's still worse than useless, thanks to its high false-positive rate. The essential randomness of the polygraphic process means that although it certainly is possible to "beat" a polygraph test, there are no guarantees; no matter how innocent you look (because you know the tricks, or because you really are innocent), the polygraph operator may still decide you're guilty.

The popular conception that a polygraph actually does "detect lies" in any straightforward sense is entirely wrong. An honest TV show should make this clear, and not give air time to someone who proudly states the opposite, whether or not that person has valid qualifications.

As psycho-quackery goes, the polygraph is a long way behind the real horror stories (like the lobotomy craze, for instance). But it still very royally deserves an "anti" Web site.

MythBusters genuinely does make an effort to get things right, which makes them almost unique in the "reality TV" field, and quite unlike certain other shows in their own niche.

This time, though, they appear to have dropped the ball very seriously indeed.

This isn't just a procedural error, oversimplification or scientific mistake on the level of getting the shape of a raindrop or the principles of operation of a wing wrong. It's a big ol' slab of prime-time bullshit.

7 Responses to “They tested the wrong guy”

  1. Alan Says:

    Dare I suggest they deliberately got it wrong? If only to give themselves the opportunity to "revisit" this topic- thus getting twice the airtime from the one idea?

  2. Lazlo Says:

    Whenever they are making fake fingerprints or mixing up explosives on Mythbusters, they always "leave out" a key ingredient or step, so as not to teach the general public how to commit mischief, and anger local law enforcement in the process.
    I don't see how they could make a show where they bust the lie detector, but "leave out" how they did it, so they decided to paint it as plausible instead. They probably felt that busting it would encourage criminals, the same way a gunpowder recipe would.

    If that is what happened, I am sad.

  3. Daniel Rutter Says:

    they always “leave out” a key ingredient or step

    Yes, at the insistence of the Discovery Channel lawyers.

    But the fake fingerprints example is a fine one, because they certainly did not change their results in that story; while they left it up to their audience to find some miscreant's Web page explaining some of the details of making fake fingerprints, they showed that those fake fingerprints worked just fine. This information could, in theory, also "encourage criminals", and the ease of making a fake fingerprint was widely known for a few years before the MythBusters story.

    (And then, of course, there's all the stories they've done before about subjects of great interest to crooks. It strikes me that the how-to-beat-the-motion-detector story, which was aired entirely unexpurgated, is of a lot more practical value to the jobbing burglar than any story about polygraphy could ever be.)

    There's no reason why the Discovery Channel lawyers would be concerned about spreading the information that polygraphs don't work. If they did work and there was some devious little-known trick you could use to cheat then there might be some sort of case to be made, but (a) they don't work, and (b) information about cheating them is widely available already.

    (Even if all you search for is the phrase "beat the lie detector", and you specifically exclude the string "mythbusters", you'll still get about 251 results, as I write this.)

    It's not illegal to know that polygraphs are garbage, and there's also nothing inherently illegal about cheating in a lie detector test. I think far more people are polygraphed by dimwitted employers than by the police, these days; if given the choice you should of course try to get a job somewhere else, but if that's not an option, it pays to know how to maximise the chance that you'll pass that bullshit test.

    This doesn't even rise to the level of cheating in a drug test, since workplace polygraphy generally has to do with establishing the general content of your character, not whether you've actually done anything illegal.

  4. Odeen Says:

    I, frankly, do not see the point of a TV show that airs, to some degree, because it is licensed by the government to do so talking about methods to subvert such government.

    I originally felt that way when Mythbusters did a "beating the speed camera" myth. Even if there is a solution to make your car invisible to police, no TV show subject to the FCC is permitted to actually reveal it. Ditto for lie detectors.

    It's different from witholding a crucial piece of information about how to make explosives - that is just a matter of keeping the less intelligent viewers, who are not capable of retrieving such information from a privately created and privately hosted website, outside of the government control from blowing himself up by accident. No - beating the speed camera and beating a polygraph is not a matter of learning how to do something dangerous or illegal - it's a matter of how to get away with what you already do or have done - the step where the government actually gets involved.

    It's a little disingenuous. I like watching a barrel of bricks land on a crash test dummy, or a guy with a beard saying that "ontogeny recapitulates phylogeny" with a French accent, as much, if not more than the next guy. Smash the two trucks together, but don't insult me by pretending to beat the speed cameras or a lie detector. Unlike the ninjas walking on water myth, they know and I know that, even if they could confirm the myth, they won't.

  5. Daniel Rutter Says:

    (That high-pitched noise you hear in the background of Odeen's comment is the Founding Fathers of the United States of America whizzing round and round in their graves.)

  6. squash Says:

    The "beat the speed trap camera" episode left me feeling a bit dry. I don't know where they got some of those methods, but they were pretty obviously not going to work. For the most part, in order for your license plate to be visible to a non-camera, it would be visible to a camera as well. I would have been interested to see some active systems... Infrared tricks come to mind...

  7. Daniel Rutter Says:

    Many of the speed-camera-beating ideas were indeed never going to work, but retroreflective license plate obscurers actually can, under certain circumstances.

    They work like any other retroreflective material (bicycle reflectors, street signs...); they reflect incoming light back to the source, no matter where the source is, usually with an array of little cube-corner mirrors. If the light source is a flash next to a camera lens, then the camera will be dazzled by its own flash and will be unable to see anything under the reflector.

    Cameras whose flash is not close to the lens will be affected less (shine a flashlight at a retroreflective street sign and move the flashlight nearer to and further from your head, and you'll see the apparent brightness of the sign change markedly). And daytime speed cameras that use normal ambient light will be completely unaffected.

    And, of course, proper retroreflective material has to be opaque in order to work. One way or another, a license plate obscurer has to appear see-through most of the time. This precludes the use of good retroreflective material.

    It's still, however, possible to coat a license plate with something that'll reflect flash-light strongly enough that it'll wash out the plate in at least some speed-camera pictures.

    The prismatic obscurers they tested showed some promise as well - they're transparent when the viewing angle is roughly perpendicular to the plate, but become more and more opaque as you get further off axis. You can see the same effect in a plastic Fresnel lens, which is probably actually what the prismatic obscurers are made from.

    Unfortunately, a prismatic obscurer that works at the relatively obtuse viewing angles of most speed cameras is one that will also be readily visible to passers-by, including passers-by in uniform. But, for what it's worth, you could see at least one of the prismatic obscurers significantly greying out the top of the plate in the MythBusters tests. In a marginal photographic situation (rain, fog, crap on the lens), it might be enough to make the difference.

    But all of these devices - even the completely useless ones like the magic spray - are thoroughly illegal in most countries, so I think you really might as well just steal someone else's plates :-).

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