'Thinking cap' makes a virtually impossible problem — possible.
In their prior research, Allan Snyder and his colleagues have found that zapping the brain leads to increased insight. Enter a recent study. Richard Chi and Allan Snyder wondered: would their electric 'thinking cap' make performance on a virtually unsolvable problem-- the nine-dot problem-- solvable?
They gave 28 healthy right-handed participants (aged 19-63) the nine-dot problem to solve. Before brain stimulation, 0 out of 22 participants solved the problem. Then they used transcranial direct current stimulation (tDCS), which is a safe, non-invasive technique that can increase or decrease cortical excitability and spontaneous neuronal firing in targeted regions. Specifically, they simultaneously decreased excitability of the left anterior temporal lobe (ATL) while they increased the excitability of the right anterior temporal lobe (ATL).
After 10 minutes of right lateralizing tDCS, more than 40 percent of the participants got the problem correct. For contrast, they placed sponge electrodes in the same positions of 11 other participants but they turned off the electrical current after 30 seconds. Therefore, these 'control' participants received the exact same experience as those in the active condition but didn't actually have their brain zapped. None (0/11) of the folks in this placebo condition solved the problem at any point during the experiment.