The researchers used a technique called transcranial direct current stimulation (TDCS, similar to the method used in this post on morality). TDCS consists of applying a weak current to a brain region (in this case, the parietal lobe, a region important for learning and understanding of math) over a given time period (in this case, 20 minutes). The technique is non-invasive, meaning they don’t open up your scalp to get at your brain: electrodes are simply place on your head (volunteers are much easier to recruit when the electrodes are on the outside, not the inside). Depending on the type of current that the researchers apply, TDCS can increase or reduce the excitation of the brain cells in the targeted region.
To test the impact of this kind of brain stimulation on math capabilities, the researchers delivered the stimulation while the participants (15 healthy adults) were learning the relative values between nine arbitrary symbols (for example, square is bigger than triangle). The learning session lasted 90 to 120 minutes. The participants received either the brain stimulation during the first 20 minutes of the session (the experimental group), or only during the first 30 seconds of the session (the control group, as 30 seconds of the stimulation is not long enough to see any effects, but still gives you the “tingles” associated with the protocol). After this learning phase, the researchers assessed the participants’ newly created sense of numerical value for the symbols with two different math tasks using the symbols. This whole process was then repeated over six days.
The results show that brain stimulation leads to better and more consistent performance on both math tasks. Mathematical ineptitude is cured! To make the matters even more interesting, the researchers called the participants back six months later and re-tested them (no brain stimulation this time). And six months later, the brain stimulation group still performed better at the math tasks involving the fake digits.
While this may sound great, don’t start tazing your brain just yet. It’s worthwhile to note that on the last day of the initial six-day study, the researchers had the participants perform the same two math tasks, but with normal numbers. In this case, there were no difference between the experimental group and the control group. This means that the brain stimulation paradigm only worked for the specific task that was learned during the stimulation, and didn’t extend to math in general. Nonetheless, the researchers suggest that brain stimulation may be a tool for intervention for those who have “developmental and acquired disorders in numerical cognition” (read: for people who are bad at math).
Must we all be good at math? There’s a French saying that goes: "ça prend toute sorte de monde pour faire un monde" (roughly translates into: "it takes all sorts of people to make a world"). What’s your take on this? Do you think this is a great advance? Do you have any concerns? Let’s hear it!
Reference: Modulating neuronal activity produces specific and long-lasting changes in numerical competence. (2010) Cohen Kadosh R et al. Current Biology 20:1-5.