"Neuroscience is in the process of reinventing itself. For 400 years, the brain was seen as a machine with parts, each performing a single mental function in a single brain location. Eventually the brain was seen as a computer with hard-wired circuits, all formed and finalized in childhood. It was believed that the brain's circuitry was only alterable in certain "critical periods," or brief windows of extreme plasticity; these were thought to occur in childhood, when experience helped to form the brain's circuitry. The conventional wisdom was that certain skills must be learned early on; it was generally "too late" for adults to pick up a new language or musical skill. Plasticity was for kids."