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NRC Panel: My paper is described in this Oct. blog entry.
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Following the theme of the recent Field Evaluations Workshop, the NYT reports that Iraqi security checkpoints are relying on bogus detectors. The operators think they work, and won't believe test results. [NYT article]


Phil Rubin's presentation at the NRC Workshop discussed the clear evidence that Voice Stress analysis doesn't work, but noted the value of "a product in the hand" and how "The urgent need for results may overshadow the often difficult and slow process of evaluation." And once you have used the device and gotten a hit, it is nearly impossible to convince you it doesn't work.

In the case of Voice Stress, however, Rubin pointed out that there is another benefit. Even interrogators who accepted the results and the order to stop using it asked if they could keep it in the room and turned on. Why? Because even though the device may not work, the person being interrogated has some belief that it might work, and if they are guilty, and the machine appears to detect some of their lies, that alone is enough to induce confession. But we Rubin points out we need to separate the fear/authority effects from the intrinsic reliability.

It may be legitimate to place a dubious device in the room if it helps elicit true confessions (without increasing false ones). Explosives are not subject to such tricks, though Schneier's post today suggests drivers might feel pressured.

But where Voice Stress researchers seemed to think they had a real effect, it seems the U.K. company knows they are selling diving rods. They have refused to submit to a test when offered $1 million for passing above random chance, and they claim the device relies on such vagaries as the operator's pulse and body temperature.

The wands sell for $16K to $60K apiece. And customers are "mostly in developing countries". Great.

Background

It seems the device and debunking is old news. But apparently they're still being sold.



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