Stories claiming that electrical brain stimulation had been used to cut sniper training time in half helped spread confusion around the nascent biohacking technique iStock/zabelin

Back in 2012, a story spread around the biohacker community that Darpa was using a new technique called tDCS to cut military sniper’s learning time in half. The story has become a great example for explaining why people should care about electrical brain stimulation. But while it might be eye-catching, it isn't true.

Not for the faint of heart, tDCS involves using electrodes to deliver short bursts of electrical current directly to the brain. One of its potential uses is to increase the excitability of the neurons, making them fire more readily and helping the brain learn new skills more quickly. Darpa’s publicised use of electrical brain stimulation to accelerate learning has fed into a hype that’s been growing for years. The sniper story was pervasive — and one I’d heard repeated countless times.


"It’s urban legend," Michael Weisend told me over lunch at the Experiential Technology and Neurogaming Conference in San Francisco. Weisend, one of the neuroscientists who worked on the Darpa program that studied brain stimulation, thinks the legend is "a good one" because of how far it spread. He explained how the confusion started, when a journalist covering his research tested the tDCS technique inside a sniper simulation and reported on her own success.

"What we actually did," he went on, "is show that we could double the rate of learning if you ask people to identify potential threats in real pictures collected from drones." An entirely different task, with no snipers involved.

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But the real story is just as impressive. Learning times were indeed cut in half, but the sniper fiction demonstrates how difficult it can be to separate hype from reality when it comes to strapping a battery to your scalp.

"There’s a distance between a research setting and the types of experiences where you can just walk up and put on a headset" Amy Kruse


Several companies now have tDCS devices ready for consumers to buy, which added to the conference hype. A spokesperson from one company, Halo Neuroscience, excitedly told me that Olympic athletes and the US Naval Special Warfare Division were already clients for their consumer product. Willing conference participants - myself included - were able to try the device, which resembles any normal pair of sleek-looking headphones. It’s only when you glance under the headband that you notice the rows of electrodes: a series of porcupine looking teeth that deliver electricity to the brain.

After several minutes of wearing the headset I felt a slight tingling sensation — but nothing unusual or unpleasant. When I described my experience to Amy Kruse, a conference speaker and the Darpa program manager who oversaw Weisend’s research, she shared her own tempered optimism about consumer tDCS.

"Some of the research data we’ve seen is quite compelling, but there’s a distance between a research setting and the types of experiences where you can just walk up — like you did — and put on a headset." According to Kruse, our brains likely require targeted placement of the electrodes to see much of a benefit. But consumer devices today don’t offer much level of precision.

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Weisend agreed that placement of the electrodes mattered, and that there needed to be more rigour in this area.


"More than 90 per cent of the research on tDCS that’s out there is done in a haphazard way," he said. "By haphazard I mean there needs to be much more rigour in the placement of electrodes and choice of electrode technologies. Further, blinding of sensations across treatment groups, and reporting of the sensations experienced by participants should be required."

Researchers typically start by stimulating different parts of the brain and then figure out what areas improved the intended outcome. "That’s a pretty standard way to operate and I think that’s backwards," said Weisend.

With funding from Kruse’s Darpa program, Weisend’s team took the opposite approach. Instead of beginning with stimulation, they first measured the brain activity of novices to see how they functioned. After the novices were trained into experts, with no stimulation involved, their brains were measured again. They then took images from both novice and expert brains and subtracted the two to uncover the parts that had changed during training. “Only then did we stimulate those parts of the brain, and when we did that we got a two-times effect.” That method, Weisend said, has been replicated multiple times.

"More than 90 per cent of the research on tDCS that’s out there is done in a haphazard way" Michael Weisend

Getting a reliable outcome, Weisend said, required a level of rigour he doesn’t yet see across the industry. "You can’t apply stimulation haphazardly without very careful thought and technique unless you’re ok with getting a haphazard inconsistent results."


Kruse pointed out that tDCS is interesting because of its relative accessibility. As it doesn’t require a clinical setup - essentially you just need a battery and something wet to put on your head — hobbyists and small teams have been free to tinker with ease. Weisend acknowledges that a few companies including his, Rio Grande Neurosciences, are taking a more rigorous approach. One company, Neuroelectrics, was at the conference to demonstrate a clinical grade tDCS device that could soon be approved by the US Food and Drug Administration to treat epilepsy.

When I asked about the electrical brain stimulation industry as a whole, Weisend suggested there were two kinds of efforts. "One is more of a parlour trick," he said. "The other is a serious effort to move to applications that might actually help people."

Aaron Frank is Principal Faculty at Singularity University