Stuart Gromley sits hunched over a desk in his bedroom, groping along the skin of his forehead, trying to figure out where to glue the electrodes. The wires lead to a Radio Shack Electronics Learning Lab, a toy covered with knobs, switches, and meters. Even though he’s working with a kiddie lab, Gromley, a 39-year-old network administrator in San Francisco, can’t afford to make mistakes: he’s about to send the current from a nine-volt battery into his own brain.
Gromley’s homemade contraption is modeled on the devices used in some of the top research centers around the world. Called transcranial direct current stimulation (tDCS), the technology works on the principle that even the weak electrical signals generated by a small battery can penetrate the skull and affect hot-button areas on the outer surface of the brain. In the past few years, scholarly research papers have touted tDCS as a non-invasive and safe way to rejigger our thoughts and feelings, and possibly to treat a variety of mental disorders. Most provocatively, researchers at the National Institute of Health have shown that running a small jolt of electricity through the forehead can enhance the verbal abilities of healthy people. That is, tDCS might do more than just alleviate symptoms of disease. It might help make its users a little bit smarter.