Tony Perry of the LA Times reports:

As Marines train to deploy to war zones, there is daily discussion about how to detect and disarm the buried roadside bombs that are the No. 1 killer of Marines in Iraq and Afghanistan.

Military researchers have found that two groups of personnel are particularly good at spotting anomalies: those with hunting backgrounds, who traipsed through the woods as youths looking to bag a deer or turkey; and those who grew up in tough urban neighborhoods, where it is often important to know what gang controls which block.

Personnel who fit neither category, often young men who grew up in the suburbs and developed a liking for video games, do not seem to have the depth perception and peripheral vision of the others, even if their eyesight is 20/20.

The findings do not surprise Army Sgt. Maj. Todd Burnett, the top enlisted man with the Pentagon-based Joint Improvised Explosive Device Defeat Organization, or JIEDDO, which conducted the study. He's made multiple deployments to Iraq and Afghanistan and ridden in more than 1,000 convoys and, on 19 occasions, been in a vehicle hit by a roadside bomb.

The best troops he's ever seen when it comes to spotting bombs were soldiers from the South Carolina National Guard, nearly all with rural backgrounds that included hunting.

"They just seemed to pick up things much better," Burnett said. "They know how to look at the entire environment."

Troops from urban backgrounds also seemed to have developed an innate "threat-assessment" ability. Both groups, said Army research psychologist Steve Burnett, "seem very adaptable to the kinds of environments" seen in Iraq and Afghanistan.

Video game enthusiasts are narrower in their focus, as if the windshield of their Humvee is a computer screen. "The gamers are very focused on the screen rather than the whole surrounding," said Sgt. Maj. Burnett (no relation to the research psychologist).

About 800 military personnel at Twentynine Palms and several other bases took part in a complex set of vision and perception tests, follow-up interviews and personality tests. Test subjects were asked to find hidden bombs in pictures, videos, virtual reality exercises and open-air obstacle courses, including on pitch-dark nights.

Although many of the findings remain classified — lest the enemy discover what the U.S. has learned about its methods of burying and detonating the devices — military officials agreed to discuss the eyesight portion of the study.

The study was completed in June, and its results are being circulated for peer review to researchers with security clearances. It took 18 months to carry out and cost $5.4 million.

After eight years of war and billions of dollars spent on electronic detection, the best technology for spotting improvised explosive devices, or IEDs, remains the sharp-eyed Marine, soldier or sailor.

Back in the 1960s, the Air Force officer qualifying exam had a 100 item Officer Biographical Inventory. The latter was a personality test that asked about "past experiences, preferences, and certain personality characteristics related to measures of officer effectiveness." It inquired into enthusiasm for sports and hunting, and was only vaguely correlated with IQ.

(A retired Air Force test psychologist told me that this section was later dropped because women did very poorly on it, and urban and suburban youths didn't do as well as country boys. "It was politically incorrect, but"—he recalled wistfully—It was a predictor of success as an officer.")

As for the guys who defuse the roadside bombs in Iraq and Afghanistan, the EODs, plain old IQ is one necessary factor. Kathryn Bigelow, director of last summer's fine Iraq movie The Hurt Locker, pointed that out in all the interviews she did.

Beaks: One thing I don't think people take into account with these guys is how highly intelligent they have to be to get assigned to a bomb squad unit.

Bigelow: That's an aspect that's very, very critical. You're invited into EOD [Explosive Ordinance Disposal] because you've scored on an aptitude test at a very high level. You're definitely a rare kind of individual. And to amplify what you're saying, you have to take into consideration that this is a volunteer military. So these are individuals who have an extremely high IQ and have chosen - after being invited into EOD - to take on the most dangerous job in the world.