For thousands of years generals such as Caesar and Napoleon have molded citizens into soldiers en masse by using the same drills and training techniques for everyone. A recent study suggests how genetic testing could enable more personalized training for today's drone operators who remotely control missile-armed Predators and Reapers.

The small study, funded by the U.S. Air Force Research Laboratory, looked at how different variants of the catechol-O-methyltransferase, or COMT, gene affected people’s multitasking performances. The gene makes an enzyme that breaks down certain neurochemicals such as dopamine, thereby affecting behavior and mood. Humans have three variants of COMT, labeled as Met/Met, Met/Val and Val/Val. These abbreviations refer to the amino acids methionine and valine in certain paired positions in the molecular structure of the enzyme. The Met and Val variants create observable differences in human behavior that have led researchers to nickname COMT the "worrier–warrior" gene.

In the study led by Raja Parasuraman, a psychologist at George Mason University and director of the Center of Excellence in Neuroergonomics, Technology and Cognition, participants trained on a simulation that required them to each control a swarm of six military drones in a battlefield scenario. The results showed that individuals who inherited the Met/Met "worrier" variant had a significant multitasking advantage over those with the Val/Met variant or Val/Val "warrior" variant in terms of how quickly they directed their drones to intercept incoming threats and efficiently destroy enemy aircraft.

Evidently, the Met/Met variant may not degrade neurochemicals as well as the other variants, so that those with the Met/Met allele “can better express dopamine in the brain’s prefrontal cortex, which allows them to perform better in complex multitasking scenarios,” Parasuraman says. “Other individuals may simply require more time or different training techniques.”

Geneticists have already known about this particular advantage of the Met/Met variant based on past experiments that tested multitasking skill using card sorting. But the new study represents one of the first to try replicating such findings in more practical scenarios. “We’ve gone beyond a simple laboratory task to a more realistic task that has commonalities with real-world tasks,” Parasuraman explains.

This also represents one of the few studies to look at the effects of COMT variants across extended training sessions. The study's 99 student participants all underwent two practice sessions lasting seven minutes each before testing their newfound skills in two more seven-minute sessions consisting of "low" and "high" difficulty. As expected, the Met/Met group showed greater improvement in multitasking performance compared with the other two groups during the course of the training.

Such work is at the forefront of neuroergonomic research aimed at designing better systems based on a scientific understanding of the brain. It represents the first genetics paper in Human Factorsa professional society publication focused on improving technological design and training.

Parasuraman hopes to eventually discover the ideal combinations of learning and training techniques for each of the COMT variants. That ability to tailor multitasking training to each individual—which could include noninvasive brain stimulation—could theoretically benefit both military personnel and civilians such as ER physicians or air traffic controllers. "Knowing individual genotypes may also help further tailor training,” Parasuraman says.

Such individualized training options would likely come at a higher cost than the current "one size fits all" approach, Parasuraman says, so cost-benefit analyses need to be done. Certainly, multitasking efficiency makes sense for the U.S. Air Force, which envisions drone operators controlling robotic swarms in future wars. (By comparison, today’s Predator drones typically require a crew of one pilot and two sensor operators.)

But the study results also imply another possible future for the U.S. military: the idea of genetically matching individual soldiers with certain roles. “The findings “could clearly be used to develop a genetic testing program,” says Mildred Cho, associate director at the Stanford Center for Biomedical Ethics.

Currently, the U.S. military has no program with the known goal of using genetic screening to assign personnel to certain roles. Still, a group of independent scientific advisors for the U.S. military, known as JASON, previously published a report in 2011 recommending the armed forces prepare for the possibility of conducting genetic research on their personnel. Cho and her colleagues detailed the implications of such genetic testing in a research highlight article for Nature Reviews Genetics. (Scientific American is part of Nature Publishing Group.)

Some ethical complications remain even if U.S. commanders only consider genetic testing for tailoring individual training. For instance, the Met/Met variant may signal a better multitasker but it is also known as the “worrier” variant, because individuals inheriting the variant have greater vulnerability to stress and lower tolerances for pain. Such knowledge would likely give the U.S. added responsibility for shielding its most vulnerable soldiers from post-traumatic stress disorder. By comparison, holders of the Val/Val variant tend to better withstand stress and pain. “Because of this issue of genes being associated with multiple things, even weakly, what you do is create is the problem of potentially finding other things that are of concern and having the obligation to do something about them,” Cho says.

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