VIDEO: The Military Discovered A Way To Boost Soldiers' Memories, And We Tried It

Oct 22, 2019
Originally published on January 8, 2020 2:54 pm

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An experiment funded by the U.S. military meant to sharpen soldiers' minds for the battlefield has found a way to improve memory: by zapping subjects' brains with tiny bursts of electricity during sleep.

In a multi-year study at the University of New Mexico, volunteers received a fraction of 9-volt battery's worth of electrical stimulation to their scalps while they slept at the lab. When they woke up, they were asked to play a video game they had learned the day before. Turns out that subjects were significantly better at it after the night spent in the lab.

In episode 6 of Future You, we try the experiment, and consider its implications for the future: What will it mean when we can learn faster and remember better simply by zapping our brains? And what if someone can overwrite our memory and manipulate what's real?

The DARPA-funded research featured here wasn't the work of UNM scientists alone. A team of researchers came together like the Justice League of memory-enhancers. The California-based science and engineering lab, HRL, a team at Rutgers University Newark, the University of Southern California, Cardiff University, and the University of California-Berkeley all played roles in the multi-site project.

Our entire Future You season is dedicated to the human body and what it will be able to do in 2050. You can find the latest episodes on YouTube or And send us your ideas about upgrading humans by email at or through Twitter, Instagram or Facebook.

: 10/21/19

A previous version of the video incorrectly referred to the neurostimulation used in the experiment as transcranial direct current stimulation. In fact, the experiment uses transcranial alternating current stimulation.

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You know, many of us would just jump at the chance to improve our memories, right? That would be amazing. Our ability to recall information can be really important to our performance in so many parts of life, everything from tests in school to the ability to master a new task at work. Well, so scientists are experimenting with ways to get our minds to better hold on to the things that we have just learned. And NPR's Elise Hu got to try one of these experiments for our series about emerging technologies called Future You. Hi, Elise.

ELISE HU, BYLINE: Hey. Good morning.

GREENE: So what exactly did you do here?

HU: Well, the idea behind this, David, is that there's something going on in our brains while we're sleeping that helps us hang onto our memories. Our brains essentially create narratives for what happened during the day, or new ideas that we were exposed to, while we're in deep sleep.

So this experiment, what it does is it stimulates the brains of subjects they're studying while they're asleep. Now, so far, this research is still in the labs, and it's not commercially available, but the results have been really promising. The experiment involves applying noninvasive electrical stimulation to our brains.

GREENE: Noninvasive electrical stimulation - what is that?

HU: So it's kind of a brain cap that you wear while you're sleeping. I tried this out at the University of New Mexico, where I went to visit the sleep lab.


HU: The researchers there introduced me to this experiment. I have to learn how to play a custom video game. And then at night, I would sleep. I'd wake up and then play the video game again. And the researchers test to see how much my performance improves. In other words, they test your memory of how to play a game.

GREENE: And why did they say video games is the best way to work on your memory?

HU: This all has to do with why it was designed in the first place. The U.S. military's research arm DARPA funded this study with the original purpose of wanting to improve soldiers' performance on the battlefield. So the task I learned was a VR game where you wear that VR headset that involves spotting and shooting targets.

Just to review, if I get it, it'll turn green, and then if I miss a human target, then it grunts.


HU: So I played this game, and I was tested after one night of sleep without any sort of brain stimulation. And then the second night, they zapped my brain while I was asleep, and then I played the game again.

GREENE: OK. Can we talk about zapping? What is zapping?

HU: OK. So the researchers put a brain cap on my head.

GREENE: Shower cap with wires coming off...

HU: Exactly. And I've worn a series of these in the Future You series. But I'm wearing that this time when I'm sleeping. And when I reach that deep stage of sleep, which is when your mind starts really consolidating memories and constructing narratives for what happened to you, the research then tracked my brainwaves and then sent electricity at the same speed as my own brainwaves back to my brain.

And this is a closed loop that's supposed to improve that process of memory consolidation that already naturally occurs. So the next morning, when tested again, many subjects showed as much as a 30% improvement in recognizing and remembering targets in the VR game.

GREENE: But how do they know that you're not just getting better at the game because you're playing the game more?

HU: Exactly. Well, the researchers adjust the scores to account for any improvements just from practice.

GREENE: OK. So what are the implications of this? I mean, it's just one kind of study with a video game. Your series, Future You, is all about imagining how all this technology advancement could change our lives in 30 years. So if they can successfully start zapping our brains when we're asleep and it improves our memory, I mean, that feels like it could be a big deal.

HU: I asked exactly that question to the lead psychologist on this research at the University of New Mexico. His name is Vince Clarke.

VINCE CLARKE: I think we'll get better at being able to enhance people's ability to learn, also things like pay attention, doing sports, and medical treatments like reducing pain.

HU: But since we are imagining the future here, I also asked him what the downside of this kind of technology might be.


HU: For example, if your memories can be boosted, could they also be erased? And here's what Vince Clark said about that.

CLARKE: You could force someone to have a memory that wasn't really true somehow, although it would take a lot more work than - what we're doing now is just enhancing a natural process. We're not really manipulating details about what you learned and all.

GREENE: That sounds bad.

HU: I had the same reaction. But the researchers tell me that we don't have to worry about this for a long while because it's like that quote that's often attributed to the sci-fi writer William Gibson. The future has already arrived, it's just not evenly distributed.

GREENE: That's a perfect quote with which to say goodbye to Elise Hu. Thanks, Elise.

HU: You bet.

GREENE: And you can see this full experiment involving brain zapping and everything else for yourself as part of our original video series Future You with Elise Hu. You can find it at, or just go to NPR's YouTube channel. Transcript provided by NPR, Copyright NPR.