March 25th, 2015
According to the headlines:
What they actually did
Researchers led by Roi Cohen Kadosh at the University of Oxford trained people on two kinds of maths skills, rote learning simple arithmetic problems and practicing more varied calculations.
During this learning process they applied small and continually varying electrical currents to the scalp, above the temples. A control group wore the electrodes but didn’t receive any current. Compared to the controls, the people who practiced with the current turned on performed faster on the maths problems.
Even more amazing, when a subset of the participants were brought back six months later, those who had received the electrical treatment were still significantly faster, albeit only for the harder, more varied, calculations.
How plausible is it?
The particular technique these researchers used, called Transcranial Random Noise Stimulation (TRNS) is a recent invention, but the use of electrical stimulation to affect brain activity has a long history.
The brain is an electrochemical machine, so there’s every reason to think that electrical stimulation should affect its function. The part of the brain the researchers stimulated – the dorsolateral prefrontal cortex – is known to be involved in complex tasks like learning, decision making and calculation.
What’s amazing is that such a gross intervention as applying a current via electrodes, to such a large part of the brain, could have a specific (and beneficial) effect on mathematical ability.
This is technically impressive work, done by highly capable researchers at well respected institutions and published in a prestigious journal. Still, there are a few warning signs that make me nervous about how reliable the result is.
Putting these worries aside, we’re not going to see this technique used in the classroom any time soon, even if it holds up. Suppose this technique is reliable, and we really can improve people’s basic maths skills with a bit of electrical stimulation we’d still hesitate to deploy it. Does it affect any other skills, perhaps taking resources away from them?
Competition is a basic principle of brain development, it isn’t implausible that there would be a cost to overclocking the brain like this. There might be all sort of minor side effects such as increased fatigue or poorer attention, which would mean that stimulation wasn’t just pure benefit. Or – also plausible – perhaps the more rapid learning of the basics would mean that skills which build on those basics would be harder to learn (sort of like screenburn for memories).
I’m not worried for the participants in this research, but I’d still want a lot more questions answered before I started setting electrical stimulation along with homework.
The original paper: Snowball, A., Tachtsidis, I., Popescu, T., Thompson, J., Delazer, M., Zamarian, L., Zhu, T., & Cohen Kadosh, R. (2013). Long-Term Enhancement of Brain Function and Cognition Using Cognitive Training and Brain Stimulation Current Biology, 23 (11), 987-992 DOI: 10.1016/j.cub.2013.04.045
Ed Yong on the dangers of neuroscience with small data sets.
Dorothy Bishop has collected some reactions to misleading headlines about ‘shocks’).
Tom Stafford does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.
Source: The Conversation.
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