For the last 20 years neuroscientists have shown us compelling pictures of brain areas "lighting up" when we see or hear, love or hate, plan or act. These studies were an important first step. But they also suggested a misleadingly simple view of how the brain works. They associated specific mental abilities with specific brain areas, in much the same way that phrenology, in the 19th century, claimed to associate psychological characteristics with skull shapes.

Most people really want to understand the mind, not the...