One might not have imagined that a star athlete with an undergraduate degree in English would go on to make remarkable contributions to neuroscience. In fact, Roger Wolcott Sperry became widely known for an astonishing career in science, pioneering ideas about the functional specialization of the cerebral hemispheres in what came to be known as “left brain” and “right brain.”
Reconnecting the Brain
Sperry was born in 1913 and grew up on a farm near Hartford, Connecticut. He earned a master’s degree in psychology at Oberlin, College, then a Ph.D in zoology at the University of Chicago. He conducted years of research at Harvard and at the Yerkes Laboratory for Primate Biology, in Florida, then, in 1954, after a presentation described as “brilliant,” Sperry began the research path that characterized his professional life, joining the California Institute of Technology faculty as the F. P. Hixon Professor of Psychobiology.
One of Sperry’s famous early discoveries involved a fundamental question of brain development. When Sperry joined Cal Tech, the predominant theory held that nerve cells and the brain as a whole started out in a simple state at the beginning of one’s life-basically as a bunch of interchangeable parts. In that view, the brain became the coordinated, complex system of the adult only after experience and education physically formed the neurons’ specific chemical characteristics.
But in dramatic experiments, Sperry found that human brain circuitry started out much more hardwired, already formed, than previously thought. That is, once the chemical nature of a specific nerve cell was set very early in development-in the embryo-that chemical nature wasn’t fundamentally changed by experience. This is why, as Sperry found, a lab animal with its nerve circuits switched from, say, the right to the left arm, wasn’t able to relearn and rewire to correct the routing. When the animal wanted to move its right arm, the left always moved instead. And this didn’t change over time.
Is Mr. Right Bright?
Sperry’s research raised questions not yet fully answered. For instance, obviously our brains do learn. But if the neurons start out so hardwired, how does learning operate? Or as Horowitz asks in a profile of Sperry, “what does learning actually consist of at the cellular and chemical level? These and other questions posed by his findings are now being studied, and no doubt they will continue to be worked on for a long time in the future.”
But Sperry made some of the most profound discoveries in neuroscience when he showed that the two sides of our brain can be independently conscious. In the 1960s, surgeons developed a procedure to cut the nerve bundle that normally connects the two hemispheres as a last resort to control difficult cases of epilepsy. Before this, the classic view of the brain was that the left brain dominated thinking and was primarily the seat of language, analysis, and high-level learned motor skills. The right, or “minor,” hemisphere was considered less highly evolved and unable to understand reading or speech. True, the right side was a whiz at recognizing faces, reading maps and dealing with other spatial relationships. Still, some scientists considered the right brain so mentally retarded that it wasn’t even conscious.
Yet, when Sperry started testing patients with split brains, he and other scientists were surprised. He found that not only could these patients continue to carry on most everyday functions after the two hemispheres were disconnected, but that the right brain wasn’t as word-deaf and word-blind as once thought. It wasn’t as advanced in language skills as the left, but patients using only their right brains could recognize such sophisticated spoken phrases as “a measuring instrument,” and could spell three- and four-letter words. Also, in split brain patients, both sides of the brain were clearly conscious, even when they weren’t aware of what the other side was seeing, hearing or thinking. While the two sides of the brain obviously worked in tandem when they were connected, they could operate independently if necessary.
Mind Over Matter
The implications of split-brain research have been widely debated. Scientists and philosophers have long argued over what is known as the mind-body quandary, the relationship between our mind and the physical brain. Some scientists saw the work of Sperry and others as supporting the notion that the brain operates almost entirely mechanically, and that consciousness, reasoning and free will have almost no effect. But Sperry strongly felt otherwise.
By comparing the interactions of normal and split brains, Sperry found what he considered science-based examples of ideas, not just chemical events, running the show. From this he developed the idea that the conscious mind and the physical brain were really part of the same continuum, or as he once wrote, “a single unified system extending from sub-nuclear forces at the bottom up through ideas at the top…Mind and consciousness are put in the driver’s seat, as it were: They give the orders, and they push and haul around the physiology and the physical and chemical processes as much as or more than the latter processes direct them.”
What this meant to Sperry was that free will, and responsibility, were no illusion. “It is possible to see today,” he believed, “an objective, explanatory model of brain function that neither contradicts nor degrades but rather affirms age-old humanist values, ideals, and meaning in human endeavor.”
Bridging the Schism
Roger Sperry won the Nobel Prize in Medicine in 1981. In his Nobel acceptance speech, he noted that split-brain studies had brought new respect, particularly among educators, for non-verbal aspects of the intellect. But more important, “The more we learn,” he told the Nobel audience, “the more we recognize the unique complexity of any one individual intellect, the stronger the conclusion becomes that the individuality inherent in our brain networks makes that of fingerprints or facial features gross and simple by comparison. The need for educational tests and policy measures to identify, accommodate, and serve the differentially specialized forms of individual intellectual potential becomes increasingly evident.”
Finally, said Sperry in Stockholm, split-brain research shows that “The whole world of inner experience (the world of the humanities), long rejected by 20th-century scientific materialism, thus becomes recognized and included within the domain of science.”
Roger Sperry died in 1994.
Michael Parrish writes about medicine, business and environmental science in newspapers such as The New York Times and magazines including Smithsonian, Health, and Life. A former reporter and editor at the Los Angeles Times, Parrish is based in Los Angeles and a contributing writer to Medical Economics magazine the Microsoft Investor and Environmental News Network Web sites. He has also written for University Access, a web-based educational publisher.
Hemisphere Deconnection and Unity in Conscious Awareness, American Psychologist, 1968.
Pucetti (1977). Sperry on Consciousness: A Critical Appreciation. The Journal of Medicine and Philosophy, 2(2), 127.
Sperry, R. W. (1977). Forebrain Commissurotomy and Conscious Awareness. The Journal of Medicine and Philosophy, 2(2), 101.
Sperry, R. W. (1977). Reply to Professor Puccetti. The Journal of Medicine and Philosophy, 2(2), 145.
Sperry, R. W. (1981). Some Effects of Disconnecting the Cerebral Hemispheres. Science, 217(4566), 1223.