Polygraph testing has no scientific basis.

[Revy]

More info here. (http://antipolygraph.org/)

I was surprised to learn that the inventor of the polygraph believed plants could read human thoughts and that there was a conspiracy in the scientific community to suppress evidence of this unusual belief.

[mikelepore]

It's based on the assumption: If you got nervous when you answered that question, your answer must have been a lie. It's as if they never heard of getting nervous when you tell the truth because you're afraid that the others might not believe you, which every human being has experienced.

[The Gallant Gallstone]

Hannah Arendt had something interesting to say regarding lie detectors in her Origins of Totalitarianism:

The lie detector is perhaps the most graphic example of the fascination that this dream apparently exerts over the mentality of all policemen; for obviously the complicated measuring equipment can hardly establish anything except the cold-blooded or nervous temperament of its victims. Actually, the feeble-minded reasoning underlying the use of this mechanism can only be explained by the irrational wish that some form of mind reading were possible at all. (p.131)

[anticap]

the inventor of the polygraph believed plants could read human thoughts

Well, they can blog (http://news.bbc.co.uk/2/hi/asia-pacific/7681966.stm)....

[Zapatas Guns]

I always thought it was funny that in the U.S. a polygraph test is not admissible in court, but to become a government agent or in a host of other private businesses a person must be subjected to a polygraph exam.

There is work being done on real mind reading devices. The American and Israeli governments are very interested in them. It works this way: They have a big picture of someone you are not supposed to like, ie bin Laden. If it does not evoke certain response in your brain then you must be a terrorist!

I tried to post a bunch of links to the company that makes this technology and the governments that are interested in it but my post count is too low. :( Anyway I expect the TSA to get this soon.

"A polygragh is able to tell if a person is being truthful or not and the WeCU (We See You) will be able to tell what a person may be up by their body language being analyzed by the system.