Thursday, November 05, 2009


To err is human; to explode, divine

Interesting article in Tuesday’s New York Times. Apparently, the Iraqi security forces have taken to using divining rods to search for explosives, against the advice of U.S. trainers and advisors.

The small hand-held wand, with a telescopic antenna on a swivel, is being used at hundreds of checkpoints in Iraq. But the device works “on the same principle as a Ouija board” — the power of suggestion — said a retired United States Air Force officer, Lt. Col. Hal Bidlack, who described the wand as nothing more than an explosives divining rod.

Still, the Iraqi government has purchased more than 1,500 of the devices, known as the ADE 651, at costs from $16,500 to $60,000 each. Nearly every police checkpoint, and many Iraqi military checkpoints, have one of the devices, which are now normally used in place of physical inspections of vehicles.

“Nothing more than an explosives divining rod,” of course, presupposes that divining rods aren’t effective. The Iraqis think otherwise:

The Iraqis, however, believe passionately in them. “Whether it’s magic or scientific, what I care about is it detects bombs,” said Maj. Gen. Jehad al-Jabiri, head of the Ministry of the Interior’s General Directorate for Combating Explosives.
Hm. “I don’t care whether it’s magic or scientific,” certainly sets a skeptic’s BS-dar beeping wildly. Has anyone looked at this seriously? Well, yes, the U.S. government’s explosives-detection experts have:
Dale Murray, head of the National Explosive Engineering Sciences Security Center at Sandia Labs, which does testing for the Department of Defense, said the center had “tested several devices in this category, and none have ever performed better than random chance.”
Our Iraqi explosives minister, though, dismissed such studies with an appeal to authority — his own:
“I don’t care about Sandia or the Department of Justice or any of them,” General Jabiri said. “I know more about this issue than the Americans do. In fact, I know more about bombs than anyone in the world.”
And that settles that.

The company that’s selling these “devices” to the Iraqis, of course, has nothing to say to the Times:

Jim McCormick, the head of ATSC, based in London, did not return calls for comment.
...but here’s what their brochure says:
ATSC’s promotional material claims that its device can find guns, ammunition, drugs, truffles, human bodies and even contraband ivory at distances up to a kilometer, underground, through walls, underwater or even from airplanes three miles high. The device works on “electrostatic magnetic ion attraction,” ATSC says.
Human bodies, distinguishing dead ones from live ones, it seems. And truffles; that’s handy. But isn’t it interesting that the list of things it “finds” are all things that we want to find. The list is so diverse that it would certainly have to also include a lot of things we don’t care about that would throw its false positive rate through the roof. But maybe it’s only certain illicit stuff that has magic fairy dust magnetic ions.

OK, so... what do we know about divining rods?

Well, we know that they were debunked so long ago that there don’t seem to be recent peer-reviewed papers on them. Nature has this study from 1971. It’s behind a paywall, but the summary isn’t:

Experiments organized by the British Army and Ministry of Defence suggest that results obtained by dowsing are no more reliable than a series of guesses.

But there’ve certainly been lots of controlled tests since then, even if they weren’t peer reviewed. And every credible test shows that divining rods are complete bunk. There’s no validity to them at all. And, in fact, the James Randi Educational Foundation made a statement about this very device last year:

No one will respond to this, because the ADE651® is a useless, quack, device which cannot perform any other function than separating naïve persons from their money. It’s a fake, a scam, a swindle, and a blatant fraud. The manufacturers, distributors, vendors, advertisers, and retailers of the ADE651® device are criminals, liars, and thieves who will ignore this challenge because they know the device, the theory, the described principles of operation, and the technical descriptions given, are nonsense, lies, and fraudulent.
That seems clear.

What studies have shown about divining rods is that they likely “work” through a form of cognitive bias. The length of the rod, along with how it’s held, amplifies the results of small arm movements. Those movements are largely involuntary, but they can inadvertently — and without the knowledge of the user — direct the rod to something we’re expecting to find. Of course, when we don’t know whether there’s really anything there, we’re either directing the rod randomly, or we’re guessing (which amounts to directing the rod randomly as well).

Or, perhaps put another way, we’ve been well trained. We’ll give General Jabiri the last word here:

During an interview on Tuesday, General Jabiri challenged a Times reporter to test the ADE 651, placing a grenade and a machine pistol in plain view in his office. Despite two attempts, the wand did not detect the weapons when used by the reporter but did so each time it was used by a policeman.

“You need more training,” the general said.

Yeah... more training. That’s the ticket.

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