“Let me put on my thinking cap” refers to a metaphorical headpiece, though the idea makes sense — sometimes, our brains seem to slow down and have difficulty thinking, so simply uttering the phrase might prime someone to get the brain ready to focus. Now, a thinking cap is no longer a metaphor — it actually exists, and yes, putting it on can actually help you think.
Robert Reinhart and Geoffrey Woodman, psychologists from Vanderbilt, recently published a study in the Journal of Neuroscience in which they demonstrate how their thinking cap works. They specifically wanted to test the medial-frontal cortex, which, among other things, causes the emission of negative voltage right after someone makes a mistake. Scientists have never understood why this happens, but Reinhart and Woodman had a theory that it’s the brain’s way of learning from mistakes. So they set about determining the purpose of those negative brainwaves. In other words, “We wanted to reach into your brain and causally control your inner critic.” They wanted to see if it’s possible to control the brain’s reaction to making mistakes, and whether that reaction could be regulated via electrical current — specifically, the current’s directional flow.
They administered a mild electrical current to the brain via an electroencephalography (EEG) cap secured with an elastic headband. For 20 minutes, the researchers conducted transcranial direct current stimulation, which involves sending a mild electrical current from the electrodes though the brain (including skin, bone, and muscle), and then completing the circuit when the current exits through another electrode. Subjects underwent three sessions and received electrical currents that ran in different directions, or the equivalent of a placebo (the mimicking of the current).
After each 20-minute session, subjects completed a trial-and-error task involving matching buttons on a game controller to colors on a monitor. The task inevitably resulted in mistakes, as any trial-and-error task does, and the likelihood of making mistakes was increased by occasionally giving participants a “do not respond” message. They also had a very short amount of time in which to complete the task, which also triggered the medial-frontal cortex’s mistake response. Throughout the tasks, the scientists monitored the participants’ brain activity to see what happened during the moments they made mistakes.
The results were stark. When an anodal current — one that started from the crown of the head and traveled down to the cheek — was applied, the medial-frontal cortex fired dramatically, about twice as much as usual for 3/4th of the participants in all experiments. Thus, they made fewer mistakes and learned faster from them. When a cathodal current was applied — travelling the opposite direction, from cheek to crown — the opposite results occurred. The subjects made more mistakes and took longer to figure out how to properly finish the task. Essentially, the experiment shows that, via electric current, the brain’s process can be adjusted to be more or less error prone, and more or less flexible and adaptable to new tasks.
The effects of the transcranial stimulation lasted roughly five hours, and affected other tasks the subjects performed in that time. In addition to improving learning, such techniques could also be used to treat ADHD or schizophrenia, or just for transhumanist fun.