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Electric "thinking cap" speeds learning

Researchers at the University of Vanderbilt have created a "thinking cap" that electrically stimulates the brain to increase its ability to learn.

(Credit: Lights of ideas image by Saad Faruque, CC BY-SA 2.0)

Researchers at the University of Vanderbilt have created a "thinking cap" that electrically stimulates the brain to increase its ability to learn.

When humans make a mistake, we have an instinctive "oops" reaction in our brains: a spike of negative voltage in the medial-front cortex. While this is something that has been observed by scientists, the reason why was a little more unclear.

(Credit: University of Vanderbilt)

To examine what effect this mistake response has on our behaviour, two psychologists from the University of Vanderbilt, Tennessee — PhD candidate Robert Reinhart and assistant professor Geoffrey Woodman — designed a cap that administers a low-level current to the brain to simulate the spike. They hypothesised that the spike plays a role in learning, allowing the brain to learn from mistakes.

"That's what we set out to test: what is the actual function of these brainwaves?" Reinhart said. "We wanted to reach into your brain and causally control your inner critic."

The cap secured two saline-soaked sponges to the test subject's head, one to the cheek and one to the crown. Through these sponges, the researchers applied 20 minutes of transcranial direct current stimulation (tCDS) — one of the safest ways to non-invasively stimulate the brain.

There were three types applied: anodal (from the crown to the cheek); cathodal (from the cheek to the crown); and control, which replicated the physical tingling sensation of tCDS without applying the current.

The subjects were then given a learning task with a high chance of making mistakes. They had to figure out by trial and error which buttons on a game controller corresponded to colours displayed on a monitor. This was complicated by occasionally showing a signal indicating the subject was not to respond; and, for even more difficulty, they had less than a second to respond correctly.

While the subjects were undertaking this task, the researchers monitored their brain activity to gauge how the brain reacted to mistakes in the moment, and observe how this activity changed under the influence of the tCDS.

What they found that was, under an anodal current, the negative voltage spike was almost twice as large as normal, and significantly higher for 75 per cent of the subjects. Their behaviour was also altered, unknown to the subjects: they made fewer mistakes and learned from their mistakes more quickly than they did under the control. Under the cathodal current, the effect was the opposite — a smaller spike and more mistakes. The effect of the 20-minute tCDS was also transferred to other tasks, and lasted about five hours.

The full study can be viewed online in The Journal of Neuroscience.