on reconciling the two hemispheres of the brain.
The Master and His Emissary: The Divided Brain and the Making of the Western World
Yale University Press, November 2010. 544 pp.
For millennia it’s been known that the human brain is divided into two hemispheres, the left and the right, yet exactly why has never been clear. What purpose this division served once seemed so obscure that the idea that one hemisphere was a “spare,” in case something went wrong with the other, was taken quite seriously. Yet the idea that the brain’s hemispheres, though linked, worked independently has a long history. As early as the third century B.C., Greek physicians speculated that the brain’s right hemisphere was geared toward “perception,” while the left was specialized in “understanding,” a rough and ready characterization that carries into our own time. In the 1970s and 1980s, the “split brain” became a hot topic in neuroscience, and soon popular wisdom produced a flood of books explaining how the left brain was a “scientist” and the right an “artist.”
Much insight into human psychology can be gleaned from these popular accounts, but “hard” science soon recognized that this simple dichotomy could not accommodate the wealth of data that ongoing research into hemispheric function produced. And as no “real” scientist wants to be associated with popular misconceptions — for fear of peer disapproval — the fact that ongoing research revealed no appreciable functional differences between the hemispheres — they both seemed to “do” the same things, after all — made it justifiable for neuroscientists to put the split-brain question on the back burner, where it has pretty much stayed. Until now.
One popular myth about the divided brain that remained part of mainstream neuroscience was the perception of the left brain as “dominant” and the right as “minor,” a kind of helpful but not terribly important sidekick that tags along as the boss deals with the serious business. In his fascinating, groundbreaking, relentlessly researched, and eloquently written work, Iain McGilchrist, a consultant psychiatrist as well as professor of English — one wants to say a “scientist” as well as an “artist” — challenges this misconception. The difference between the hemispheres, McGilchrist argues, is not in what they do, but in how they do it. And it’s a difference that makes all the difference.