Can Small Doses of Electricity Make You Smarter?

Maybe, but at what cost?

My kids, ages 10 and 14, do well in school. They’re curious and generally like to learn. But they have weak spots: Spanish and science are not their strong suits. What if I could juice their abilities in these areas so they could grasp calculus or verb conjugates or learn to play a tune by ear? I’d definitely consider that, particularly if the method didn’t involve drugs or require surgery.

Vincent Clark, a neuroscientist at the University of New Mexico, thinks this is eminently possible. He’s among a small but growing group of neuroscientists around the world who are examining the possibility that sending minimal doses of electricity into the brain can enhance learning, cognition, and creativity. These researchers say the technique—known as transcranial stimulation, because it sends a current through the scalp and into the cortex—has potential in a range of educational contexts: people with learning disabilities, patients recovering from strokes or dealing with neurological diseases, as well as run-of-the-mill students learning to speak a language, paint, or play the trombone.

“I really think this technology can transform how we learn,” says Clark. “From what we’ve seen so far, it looks like we can alter the brain to make it more efficient.”

In broad terms, the technique is relatively straightforward: Electrodes attached to the subject’s head send a small current of electricity into the brain. The key is in the details. Depending on where the electrodes are placed on the scalp, and the strength, duration, and frequency of the current, the stimulation can have a wide range of cognitive effects.

The technique comes in several flavors, each with its own manner of generating and delivering the electric current: transcranial magnetic stimulation (TMS) uses magnetic coils to generate electricity, direct current stimulation (tDCS) uses a steady flow of electricity, alternating current stimulation (tACS) uses a current that turns on and off, and random noise stimulation (tRNS) varies the current without a preset pattern. Researchers have found differences in how each approach affects the brain, but there is little consensus on which approach works best for a specific purpose.

Over the past decade, dozens of studies have found evidence that
transcranial stimulation can improve some aspect of brain performance, including attention, memory, math proficiency, reaction time, and creativity. In many of these studies, the increased knowledge or skill persists for days or weeks after the stimulation, which suggests that the effect is lasting.

In 2012, Clark published a study examining how the technique affected the ability to spot objects camouflaged within a picture. He found that subjects who received the stimulation learned twice as much, on average, compared with those who received “sham” stimulation (they were hooked up to electrodes but didn’t receive any current). He and other researchers have since repeated the experiment three times and found the same results.

Transcranial stimulation seems especially effective at boosting motor skills. Many scientists, including Clark, think it could be helpful in speeding recovery for stroke patients who have lost the ability to walk, talk, or perform other physical activities. More broadly, the technology could improve learning in any task that involves physical movement or spatial understanding.

Using electricity to adjust the human brain is not new. For decades, patients with depression have been treated with electroconvulsive therapy (ECT) and deep brain stimulation. But these techniques are much more involved than transcranial stimulation. ECT delivers a much larger current—about 400 times more powerful than transcranial stimulation—and is generally used only for severe cases of depression. Deep brain stimulation, also typically used for depression, as well as Parkinson’s disease, involves surgically implanting electrodes deep within the brain. Transcranial stimulation, by contrast, is much less intrusive. Many subjects don’t even feel the current during sessions.

This is one key reason that the approach is so promising: Because transcranial stimulation is relatively uncomplicated, one could imagine it being used in all kinds of learning situations.

A few scientists have begun examining the technique for use in educational settings with children. Roi Cohen Kadosh, a neuroscientist at Oxford University, has begun an experiment looking at whether repeated sessions of brain stimulation can help children who are having trouble with math. “We need to answer a lot of questions, obviously, but this has really strong potential to be used in education,” says Cohen Kadosh, who recently published a study showing that brain stimulation could significantly improve math ability in healthy adults. Like everyone I spoke with, Cohen Kadosh didn’t want to hazard a guess about if or when the technique might be used widely. He says that if it turns out that the technique works, transcranial stimulators should be regulated as medical devices, because they would treat medically recognized conditions such as dyslexia or its math equivalent, dyscalculia. The U.S. Food and Drug Administration (FDA) oversees medical devices and requires rigorous testing to prove safety and effectiveness. This process typically takes years.

The FDA has approved transcranial stimulation in two forms. TMS is allowed for the treatment of migraines and severe depression, and one tACS device is approved for depression, anxiety, insomnia, and chronic pain. Even so, some people, including a few parents, are already using TMS and other forms of transcranial stimulation on themselves and their kids in an effort to improve learning and cognition. A few companies sell the devices but explicitly state that the machines are not for medical use. It is hard to know how many are experimenting on themselves and their children in this way, but the community has a thriving online presence.

It’s not clear exactly how transcranial stimulation works. Some studies have found that brain areas stimulated by electricity experience increases in glutamate, a neurotransmitter that can play a key role in learning and cognition. Stimulation also seems to change the rhythm of neuronal firing in the brain. These rhythms, known as oscillations, appear to play a key role in how the brain relays information from one area to another.

“Oscillations are the main communication mode for the brain,” says Flavio Frohlich, a neuroscientist at the University of North Carolina who has studied brain stimulation for more than a decade. “They are central to cognition and behavior. And we can target these rhythms with stimulation.” Frohlich has found that applying stimulation in the alpha frequency — between eight and 12 Hertz — can substantially increase creativity, as measured by the ability to create pictures from a series of random lines and shapes.

Of course, there are caveats. Most of the studies have been small, and many have not been replicated. Many studies have measured the ability to perform narrow tasks, such as pushing a lever when a light flashes, not the kind of complex cognition that is so often required in the everyday world.

In addition, some scientists suspect that the brain may be a kind of zero-sum machine — that improving abilities in one area may cause related declines in other domains. Juicing proficiency in one field looks less inviting if you must simultaneously scale back learning elsewhere.

And sending even small amounts of electricity into the brain is not without risks: Frohlich published a study last year that found tDCS actually worsened performance on an IQ test.

Moreover, not everyone is on the bandwagon. A review published last year by Jared Horvath, a neuroscientist at the University of Melbourne, found that a single session of tDCS was ineffective for improving learning in any context. He argues that positive results have not been repeated and so cannot be considered legitimate. Clark and Nitsche strongly disagree with his view, arguing, among other things, that he unfairly excluded many positive studies.

It is far too soon to make conclusions about the technique, proponents argue. “We are in the Model T stage of this,” says Marom Bikson, a biomedical engineer at the City College of the City University of New York who has studied brain stimulation for the past decade. “I’m really enthusiastic about this. But I’m also really cautious. It is so, so new.”

Bikson and others emphasize that transcranial stimulation isn’t magic — it won’t allow students to grasp a subject or skill without effort. “This kind of intervention might improve learning, but that doesn’t mean you don’t have to apply yourself,” says Michael Nitsche, a professor of neurophysiology at the University of Goettingen in Germany. “There is no shortcut that will teach you Chinese without a lot of work.”

Then there’s the moral issue. Nitsche, who has been studying transcranial stimulation for nearly two decades, notes that it has the potential to become the cognitive equivalent of performance-enhancing drugs in sports.

Is it fair for one student to take a test after studying with transcranial stimulation while another must stick to traditional methods? “This could potentially increase inequality even further,” says Nitsche. “It could be a huge advantage for the wealthy people who could more easily afford it.”

But even with all of these potential obstacles, transcranial stimulation remains deeply intriguing as a potential educational tool. This brings me back to my two daughters. Who wouldn’t want their kids to be smarter? I want them to get into good colleges and have satisfying careers. Could brain stimulation help them do that? Judging from my conversations with researchers, that certainly seems conceivable at some point in the near or not-so-near future.

Like Nitsche, I worry that the rise of neuroelectric training would widen the gap between the haves and have-nots in education. But what makes me just as uncomfortable is the possibility that brain stimulation would add more stress to the already pressurized, supercompetitive, overscheduled lives that so many kids lead. I plead guilty on this count: I’m not as bad as some (at least I hope not), but if I’m honest, I have to admit that my kids participate in too many activities and have too little free time. The idea that we may one day feel obligated to squeeze in yet another undertaking in our drive to ensure maximum achievement and that the arms race to college and adult success could include another weapon does not fill me with unalloyed excitement.

So, as exciting as this research is, and as much as I’m intrigued with the idea that my kids (or me, for that matter) could become smarter and more creative with the help of a little well-placed electricity, I also wouldn’t mind if these devices take a few decades, rather than a few years, to become reality.

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