The Right (and Left) Stuff

"Our brains are extraordinary. Yet for all the brain’s complexity,its broad topography is simple and symmetrical. Scientists have long known that a neurological Mason-Dixon Line divides the brain into two regions.And until surprisingly recently,the scientific establishment considered the two regions separate but unequal.The left side,the theory went,was the crucial half,the half that made us human. The right side was subsidiary — the remnant,some argued,of an earlier stage of development. The left hemisphere was rational,analytic and logical. The right hemisphere was mute,nonlinear and instinctive — a vestige that nature had designed for a purpose that humans had outgrown.

This view prevailed for much of the next century —until a soft-spoken Caltech professor named Robert W.Sperry reshaped our understanding of our brains and ourselves. In the late 1950s,Sperry studied patients who had epileptic seizures that had required removal of the corpus callosum,the thick bundle of some 300 million nerve fibers that connects the brain’s two hemispheres.In a set of experiments on these “split-brain”patients,Sperry discovered that the established view was flawed.Yes,our brains were divided into two halves. But as he put it,“The so-called subordinate or minor hemisphere,which we had formerly supposed to be illiterate and mentally retarded and thought by some authorities to not even be conscious,was found to be in fact the superior cerebral member when it came to performing certain kinds of mental tasks.”In other words,the right wasn’t inferior to the left. It was just different.

Thanks to Sperry’s pioneering research and the advent of technologies like the fMRI (functional Magnetic Resonance Imaging) that allow researchers to watch the brain in action,the right hemisphere today has achieved a measure of legitimacy. It’s real. It’s important. It helps make us human. No neuroscientist worth his or her Ph.D. ever disputes that. Yet beyond the neuro-science labs and brain-imaging clinics,two misconceptions about the right side of the brain persist."