'Non-Invasive Polygraph' Uses Infrared Light

opticsorg writes "Infrared laser pulses could soon be used to determine whether someone is telling the truth or is under stress. In patent application WO 03/057003, US firm Defense Group describes a non-invasive polygraph machine that fires infrared pulses at the subject. The reflected and scattered pulses are gathered and analysed by a receiver. 'The receiver is connected to an information processing device capable of determining various physiological characteristics exhibited by the human subject,' say the authors." Whether "various physiological characteristics" are reliable signs of truth-telling is another issue, though.

Comments

This would make politics interesting

[Phillup]

Wouldn't it be cool to have one pointed at every politician, every time they made public statements?

Polygraph story

[Laplace]

So I knew this woman, a world class athlete, who also worked for the Department of Defense. For her Top Secret clearance she had to submit to a polygraph test every six months. On the day of one of her tests she arrived at the testing center having just worked out. Her pulse, respiration, and skin moisture were all a bit elevated, and the tester noted these abmornal readings to her. Now, one of her training techniques involved meditation, and she became adept at both mentally and physically relaxing in a very short amount of time. She went into her meditation routine and almost instantly her pulse and breathing rate dropped. The tester became angry with her, and told her to come back the next day. Now how hard can it be to learn to game the whole polygraph system?

Re:Polygraph story

[Sylver Dragon]

Sorry, bit of a typo there. Though I still stand by my assertion polygraph tests are junk science. If you haven't done so, I would recommend reading The Lie Behind the Lie Detector (PDF), its a good read and very informative about polygraph tests and the like. Polygraphs are just the moden day version of a mystic. They don't do anything in and of themselves, they only convince people to confess, and are great for destroying someone's credibility because the media believes in them.

Re:Still subjective measurements

[tanguyr]

Sir Bedevere: There are ways of telling whether she is a witch.
Peasant 1: Are there? Oh well, tell us!
Sir Bedevere: Tell me. What do you do with witches?
Peasant 1: Burn them!
Sir Bedevere: And what do you burn, apart from witches?
Peasant 1: More witches!
Peasant 2: Wood!
Sir Bedevere: Correct. Now, why do witches burn?
Peasant 3: ...because they're made of... wood?
Sir Bedevere: Good. So how do you tell whether she is made of wood?
Peasant 1: Build a bridge out of her!
Sir Bedevere: But don't we also build bridges out of stone?
Peasant 1: Oh yeah.
Sir Bedevere: Now, does wood float in water?
Peasant 1: No, no... Throw her into the pond!
Sir Bedevere: No, no. What else floats in water?
Peasant 1: Bread!
Peasant 2: Apples!
Peasant 3: Very small rocks!
Peasant 2: Cherries! Great lumpy gravy!
Peasant 3: Crutches!
King Arthur: A Duck!
Sir Bedevere: Exactly!

An alternative to classic lie detector

[FrankoBoy]

is found in new techniques involving brain scans. A brain wave pattern called P300 ( "positive wave" 300 ms after onset ) has been discovered to be activated when a person looks at a familiar object ( the P300 hypothesis has gained very solid evidence since a few years ). So you can display some pictures to the accused person and embed in these actual crime scenes pictures, and then tell if the accusee is familiar with crime scene pictures ( like what the place looked like, weapons involved, etc. ). Of course, you have to display pictures that has not been released to the media and whatnot, but the uniqueness of the combinations needed to figure out that someone is involved in the crime is pretty high. Links here, here and here.

This polygraph stuff got to be thrown away at some point anyway, since it's based on reaction patterns that many people just don't have so its accuracy isn't high enough for the important task it has to do.

Consumer Grade Unit

[4of12]

Infrared laser pulses

(Wife points TV remote at hubby.)

"Now tell me again where you were until 2:30 last night! And don't think you can get away with lying - I've got my IR polygraph aimed right at your forehead!"