The Medtronic was originally developed as a tool for brain surgery: by stimulating or slowing down specific regions of the brain, it allowed doctors to monitor the effects of surgery in real time. But it also produced, they noted, strange and unexpected effects on patients' mental functions: one minute they would lose the ability to speak, another minute they would speak easily but would make odd linguistic errors and so on. A number of researchers started to look into the possibilities, but one in particular intrigued Snyder: that people undergoing transcranial magnetic stimulation, or TMS, could suddenly exhibit savant intelligence -- those isolated pockets of geniuslike mental ability that most often appear in autistic people. [...]

As remarkable as the cat-drawing lesson was, it was just a hint of Snyder's work and its implications for the study of cognition. He has used TMS dozens of times on university students, measuring its effect on their ability to draw, to proofread and to perform difficult mathematical functions like identifying prime numbers by sight. Hooked up to the machine, 40 percent of test subjects exhibited extraordinary, and newfound, mental skills. That Snyder was able to induce these remarkable feats in a controlled, repeatable experiment is more than just a great party trick; it's a breakthrough that may lead to a revolution in the way we understand the limits of our own intelligence -- and the functioning of the human brain in general.

And so Snyder turned to TMS, in an attempt, as he says, "to enhance the brain by shutting off certain parts of it." [...] If Snyder's suspicions are correct, in fact, and savants have not more brainpower than the rest of us, but less, then it's even possible that everybody starts out life as a savant. Look, for example, at the ease with which children master complex languages -- a mysterious skill that seems to shut off automatically around the age of 12. "What we're doing is counterintuitive," Snyder tells me. "We're saying that all these genius skills are easy, they're natural. Our brain does them naturally."