'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

Inadmissability of polygraph results

[Dancin_Santa]

Maybe if they'd require them, we'd have found the real killers by now.

Starburst: The Juice is Loose

another issue?

[Hubert_Shrump]

Whether "various physiological characteristics" are reliable signs of truth-telling is another issue, though.

You question our methods, terrorist?

Perhaps it is you that stole the stapler!

Since when were standard polygraphs invasive?

[HaloZero]

invasive ( P ) Pronunciation Key (n-vsv)

adj.

1. Of, engaging in, or given to armed aggression: an invasive military force.
2. Marked by the tendency to spread, especially into healthy tissue: an invasive carcinoma.
3. Of or relating to a medical procedure in which a part of the body is entered, as by puncture or incision.
4. Tending to intrude or encroach, as upon privacy.

Polygraphs have consisted of blood-pressure monitors, pulse/respiration monitors/graphing, temperature, relative humidity/condensation on the epidermis, and as of late, retinal imaging. These are usually accomplised by a series of patches attached to the EXTERIOR of the patient's skin. No where, no how, is anything poked, prodded, or inserted.

If my invasive, you mean, less cumbersome, then sure, maybe. The patient would still have to breathe normally, and hold perfectly still (as to not alter the readings taken by the IR), which is really the only cumbersome thing about it.

Re:Since when were standard polygraphs invasive?

[Anonymous Coward]

not quite.

the poly i was given (it was for a gov't security clearance, and part of a larger background investigation for that clearance) consisted of a pair of sensors on two of my fingers (IIRC, index and middle; detects sweating), a pair of cords across my chest and stomach (monitors breathing), and a blood pressure wrap reader on my upper arm (blood pressure (duh) and heart rate). and you get a nice leather reclining chair to sit in. no patches slapped to my skin anywhere.

not sure how much retinal imaging would do, i was allowed to close my eyes as long as i didnt fall asleep.

they say "breathe normal," knowing full well the subject being interviewed is going to be nervous as hell, even when they are telling the truth. my breathing was more of a forced deep rhythm.

Re:Since when were standard polygraphs invasive?

[schlyne]

Supposedly, the retinal imaging section of the test is more reliable. If the pupil dilates suddenly, the person is lying.

Re:Since when were standard polygraphs invasive?

[LudditeMind]

I think what they're trying to say is that it could be used on you without your knowledge. Granted I would consider that more invasive, but it depends on your perspective.

This would make politics interesting

[Phillup]

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

Re:This would make politics interesting

[eglamkowski]

There'd be no point - it'd go off every time the politicians moved their lips.

Still subjective measurements

[neitzsche]

All "lie detector" tests are bogus because the results are always "subjective" to the machine's operator. This one is no improvement on the old [also invalid] concept.

Anyone know when this concept was first used? Sending someone to stand in front of a mystic or seer so as to evoke a confession?

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!

Re:Still subjective measurements

[outlier]

All "lie detector" tests are bogus because the results are always "subjective" to the machine's operator.

Not quite. Polygraphs can be valid under the right circumstances. They are reasonably accurate when used to ask questions about specific instances. Less so when they are used in hiring decision contexts. See this recent report from the National Academy of Science. There are many effective countermeasures to "fool" a polygraph. I wouldn't want my future (guilt or innocence) to depend on one, but they are pretty good at recognizing when people have unusual reactions to stimuli. How they are interpreted (e.g., is that a 'lie' or just nervousness?) is another matter.

Anyone know when this concept was first used?

The use of the polygraph as lie detector was pioneered by psychologist Dr. William Moulton Marston. He may be more familiar to Slashdotters under his pseudonym Charles Moulton. That's the name he used when he created the comic book "Wonder Woman."

Seriously!

Re:Still subjective measurements

[outlier]

Two points:

First, you are on the right track in pushing for a double-blind, methodologically sound study. However, the value of analyzing "a number of older experiments performed by a variety of organizations" should not be underestimated. In many ways a meta-analysis (evaluation of existing analyses) is actually more reliable than a single well designed study. No matter how well it is designed, any single study will have weaknesses -- they have a small number of subjects, the truths/lies are limited to a single domain, the time and location of the study has some unexpected influence on the results, etc.

By combining these studies, organizing them by potentially meaningful variables (question type, subject pool, etc.), and weighting their influence by the number of subjects (bigger studies are more important than small ones), you essentially cancel out a lot of the noise (e.g., experimenter bias, weird questions or instructions, etc.)

Second point: The polygraph is reasonably valid as a lie detector. I'd characterize their accuracy as "better than most people, but not good enough to execute someone." Unaided humans in studies similar to the one you outline above perform in the 55-65% range. Significantly better than chance, but not particularly awe inspiring. Moreover, police officers, judges, customs agents, FBI agents, and college students all tend to perform about the same. Some Prisoners, Secret Service Agents, Psychologists interested in deception, and some people who have grown up in abusive environments have been shown to perform even better. But accuracy tends to be pretty domain specific.

The polygraph can arguably be characterized as having an accuracy as a lie detector in the 60-80% range. There are people (and organizations) that will claim accuracies in the 95-100% ranges, as well as those who would argue that the accuracy of the polygraph is 55% or lower. In both cases, you're probably dealing with people who have hidden (or not so hidden) agendas.

Again, the polygraph is a decent tool to determine if someone reacts unusually to some stimulus. Any assumptions beyond that may be unfounded.

If it really worked

[ClosedSource]

the medical applications would be far more important and profitable then the "lie detecting" application. The fact that it wasn't a patent for a medical device suggests that it doesn't really measure anything meaningful.

Since there is no scientific standard for lie detectors (and the current ones are obviously a scam), you can use any kind of dubious technology you like. A medical device, however, has to demonstrate efficacy which is a much higher standard.

Re:If it really worked

[jdiggans]

Near-infrared neural imaging is already a very useful technique.

This is a new application whether or not you approve.
-j

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]

That's a crock of shit.

Stop right there. You have just described the whole "science" of polography. The only reason it sticks around is there is enough money being pumped into it, that the purveyors of this snake oil can keep lots of people convinced that it works. The only thing it is useful for is convincing weak minded idiots that you actually have a way to see inside their heads, and get them to confess. Other than that, it is total bunk.

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:Polygraph story

[Incongruity]

"Now, we're not talking about things like heart rate and respiration here, although those are observed. We're talking about things like galvanic skin response, which basically measures how sweaty you are at a very fine level of detail. These are not things you can change with rhythmic breathing or whatever. They are beyond your conscious and autonomic nervous systems and into the realm of physiological response."

How about you stop right there and go and read up a bit more. Galvanic skin responses can be ellicited by *a lot* of conciously controlled actions. If you take a sudden, strong sniff of air, for example, you'll see a really big GSR. That's an easy one. Also, btw, GSR *is* an autonomic response. If you doubt me on either of these two points, go ahead and read the recently published report on the scientific basis for the polygraphby the National Academies of Science. You can find it online and read it for free.

Re:Polygraph story

[alecto]

The only reason it sticks around is there is enough money being pumped into it, that the purveyors of this snake oil can keep lots of people convinced that it works.

Kind of like DRM, in that respect.

Re:Polygraph story

[ThereIsNoSporkNeo]

They couldn't come up with a color for "Modern day torture"... or, more accurately, it was already taken by the "Games" section.

Since they started using the 4th definition

[morcheeba]

4. Tending to intrude or encroach, as upon privacy.

If there is anything that should be private, it should be one's own thoughts. Attempting to read these is invasive.

Polygraphs are a Fraud

[jazman_777]

Read about it here. Looks like polygraphs are biased against honest people.

Great

[joelt49]

Great, another machine to do the impossible. I mean, really, how is this different than just looking someone in the eye when you ask them a question? Some people can lie convincingly and others can't. That's all there is to this system. Once you have a system, you CAN beat it, and some people do. Why don't we just accept that fact and get rid of polygraph machines? Either that, or have an experienced poker player read the results, as they have TONS of experience with poker-faces.

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!"

Different path

[Armbrust84]

I just wonder if there is anyone out there who is combining the new insights we gain each week into the workings of th emind with the newest theories and practices of forensic investigation. Seems to me that we cannot rely on only one method. Although, ever more frequently, the police require less evidence to arrest, and judges/juries even less to convict. Oh well, I pity my great-grandchildren.