The build team tests out ways to beat the lie detector... do they succeed?

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MythMod

I have been a polygraph examiner in law enforcement for ten years. You guys did a great job on the segment! Thanks!

Hey everyone I liked this episode and wanted to share a website I found about Polygraphs Antipolygraph

***I have no affiliation with that site and make no claims to its validity***

man i was hoping tha gun would work but thats amazing 700 yards very pleased w/ this episode

Antipolygraph will discuss the exact countermeasures used in the episode. The bottom line is an experienced examiner is very difficult if not impossible to beat. If you are truly interested in polygraph and its accuracy try the American Polygraph Association website.

A great job on the steam gun except I'm shocked they opted for steel instead of lead for the shot. Anyone into guns knows that steel rounds are a lot less effective than lead. It might have made the difference in the impact tests.

Also I think the hang up was with using the 12 rounds at once. The issue was the rounds needed to be able to leave the barrel over the distance of the openning or risk being partly out of the barrel when it passed in front of the shroud.

Lots of fun I'd just love to have seen it with lead rounds.

One thing I found funny with the polygraph was I knew they'd fail as soon as Adam gave the "reward - punishment". That "small" thing caused a bit of anxiety in them, enough that they'd be stressing more over the lies than they would've before hand. Meaning that when they were lieing, not only were they concentrating on fooling the test, but they were also at some level thinking "I don't wanna wash the cars!".

With the MRI based one (can't remember it's actual name), I had a pretty good idea Grant would have the greatest chance of getting away with it. Different parts of the brain are divided into specific tasks (ex: creative and logic) if you lie, your brain patterns for creative should be active which shouldn't be if you were telling the truth. His method should've clouded the results. The other two picked (were given, whichever) things that should of been as useless as taking a cooking class to learn to scuba dive.

I think that the lead shot is key to the confederate steam driven machine gun myth. Lead has a molecular weight 4 times that of steel. So by my rough calculations that would be 4 times the energy if the machine could throw the balls at the same speed. I don't think that would be a problem because it didn't seem underpowered in any way. If the steel balls were close the lead balls very well could be leathal.

Also, the machine in the picture seemed much bigger. Large diameter shot would have more mass delivering more energy (you get the idea).

This would be a great revisit!!!

I think a shot with a smaller diameter would also work better than the ammo used in this episode. Ammo with a smaller surface area would have a higher velocity and possibly penetrate the skin of the target rather than glance off like the larger rounds did.

I also think that using lead shot would be worth a try as well.

You're not really proving anything if you use modern machining and extruded pipe, not to mention ball bearings. Period steam engines would be slow low tolerance bore devices that could work on primitive bearings. No power turbines until several decades later. Try cutting the speed so you could have a piston driven device running on lignum vitae bearings and pushing cast lead shot through a hand forged barrel. Think of automating a parthian sling rather than a modern machine gun and you have something that would impress the period soldier.

Great episode.

Smaller shot, longer barrel.

there was an experienced, trained polygraph examiner on this show. He has the experience if someone is telling the truth or lying. the build team was inexperienced in taking the test. i would've like to have seen people who spy or who are secret agents. i would think that their training would cover polygraph tests on how to beat the test.

Another meathod I've heard is to stress yourself. Raise your heart rate and blood pressure intentionally, then allow yourself to relax a bit when telling the lie around which the case rests. The theory being that since you relax for that particular question, you are less likely to be lying.

I don't know if that would work, but it would certainly be worth testing.

quote:

Originally posted by dagorin:
Another meathod I've heard is to stress yourself.....

That's what Grant attempted I believe. Not sure exactly how his results were -- but the polygraph examiner said his sweat gave him away. After a while it'd wear the person down though, tests can run from like 2-6 hours I think (or longer, non-stop).

But they did try to test it.

Apparently I don't have permission to edit my own posts now...

Anyway I was going to add that they missed one very important thing that they should've tested: whether an innocent person that feels guilty or just wants to be found guilty can be proven "guilty" by the machine and examiner.

From what the announcer said, Kari wasn't trying to lie, she was being honest.

But they needed a person that did everything that she did, only try to get all sweaty and nervous only when telling the truth about stealing the money. That is "did you enter the room today"--"yes [acting normal]", "did you steal the $50?"--"no [trying to act nervous and sweat, like thinking of something else they stole]"

One odd thing about them doing this myth was the part about having to wash all the cars and riding the bus a long way home if they couldn't beat the test.
That seemed like a mean thing for the producers to do.

quote:

Originally posted by jd2666:
One odd thing about them doing this myth was the part about having to wash all the cars and riding the bus a long way home if they couldn't beat the test.
That seemed like a mean thing for the producers to do.

Well, the washing the cars was just part of the test -- throw them off so they'd be more anxious (worried about making sure they could lie) so they'd "fail" the test.

But the bus ride... that was just mean. Given how the MRI based test is based on (from what I've read/seen) as long as you have brain activity, can read, and can push buttons it'll work. It was practically guaranteed that they'd be taking the bus back home.

quote:

Originally posted by jlrodgers:
Well, the washing the cars was just part of the test -- throw them off so they'd be more anxious (worried about making sure they could lie) so they'd "fail" the test.

If it was for the test then there was no reason to actually have them wash the cars after the test was done. Or at least not all the crew member's cars.

Edit: I just watched the recording again and it was washing, waxing and polishing the cars.

quote:

Originally posted by jd2666:
If it was for the test then there was no reason to actually have them wash the cars after the test was done. Or at least not all the crew member's cars.

Edit: I just watched the recording again and it was washing, waxing and polishing the cars.

You'd have them do it still since they'd expect it. Not to mention they decided to do the same ploy the second time. If it was stated "it was for the test" then the other time it was done wouldn't of had the desired effect (depending on shooting order, either the "bus ride or $1000" was first, or the "first-class plane ticket or wash/wax/polish cars"). If they hadn't of done it, the second time they'd of known it was a hollow threat, so they'd have no anxiety over it (nor any incentive to do well).


Basically, you don't want your mice knowing they're in a maze, especially if they still have to perform as if they don't know.

quote:

Originally posted by Chouette:
Hey everyone I liked this episode and wanted to share a website I found about Polygraphs Antipolygraph

***I have no affiliation with that site and make no claims to its validity***

I'm a co-founder of AntiPolygraph.org. We're a non-profit, public interest website dedicated to exposing and ending waste, fraud, and abuse associated with the use of polygraphs and other purported forms of "lie detection" (such as voice stress analysis).

We provide information on polygraph countermeasures (methods for passing or beating a polygraph) in Chapter 4 of our e-book, The Lie Behind the Lie Detector, which may be downloaded as a 1 mb PDF file here:

http://antipolygraph.org/lie-behind-the-lie-detector.pdf

While there is quite a bit of folklore on how to beat the polygraph, the information in our book is based on peer-reviewed academic research and U.S. Government documentation. And it is well-referenced with footnotes and an annotated bibliography.

I haven't yet seen this episode of Mythbusters, and thus cannot comment on it. But I think a better myth to explore would be the notion that there is such a thing as a machine that can detect lies. There is broad consensus amongst scientists that polygraph testing is without scientific basis. Yet the myth of the polygraph persists.