If you’re anxious about maths, zapping your brain could help (Image: Getty)

Zapping your brain might make you better at maths tests – or worse. It depends how anxious you are about taking the test in the first place.

A recent surge of studies has shown that brain stimulation can make people more creative and better at maths, and can even improve memory, but these studies tend to neglect individual differences. Now, Roi Cohen Kadosh at the University of Oxford and his colleagues have shown that brain stimulation can have completely opposite effects depending on your personality.

Previous research has shown that a type of non-invasive brain stimulation called transcranial direct current stimulation (tDCS) – which enhances brain activity using an electric current – can improve mathematical ability when applied to the dorsolateral prefrontal cortex, an area involved in regulating emotion. To test whether personality traits might affect this result, Kadosh’s team tried the technique on 25 people who find mental arithmetic highly stressful, and 20 people who do not.


They found that participants with high maths anxiety made correct responses more quickly and, after the test, showed lower levels of cortisol, an indicator of stress. On the other hand, individuals with low maths anxiety performed worse after tDCS.

“It is hard to believe that all people would benefit similarly [from] brain stimulation,” says Cohen Kadosh. He says that further research could shed light on how to optimise the technology and help to discover who is most likely to benefit from stimulation.

Settling the debate

A recent review analysed several brain-stimulation studies and found them wanting: the authors concluded that few stimulation studies have significant effects on the brain. Cohen Kadosh suggests that his study might explain why some researchers do not always find clear effects from brain stimulation – because they do not separate people according to specific traits that might affect the results.

Sven Bestmann at University College London says the study’s look at personality traits is interesting, but he warns that these results only apply to this specific task and group of people. “Unfortunately, we also have no understanding of the mechanism that caused the results, so at present these types of result may be hard to independently replicate,” he says.

Journal reference: Journal of Neuroscience, DOI: 10.1523/jneurosci.3129-14.2014