Roger W. Sperry Biography (1913-1994)
Roger Sperry was born on 20 August 1913, in Hartford, Connecticut. When Sperry was 11 years old, his father died and his mother returned to school and gota job as an assistant to a high school principal. Sperry attended local public schools through high school and then went to Oberlin College in Ohio on ascholarship. Although he majored in English, Sperry was especially interestedin his undergraduate psychology courses with R. H. Stetson, an expert on thephysiology of speech. Sperry earned his B.A. in English in 1935 and then worked as a graduate assistant to Stetson for two years. In 1937 he received anM.A. in psychology.
Thoroughly committed to research in the field of psychobiology by that time,Sperry went to the University of Chicago to conduct research on the organization of the central nervous system under the renowned biologist Paul Weiss. Before Weiss's research, scientists believed that the connections of the nervous system had to be very exact to work properly. Weiss disproved this theory by surgically crossing a subject's nerve connections. After the surgery was performed, the subject's behavior did not change. From this, Weiss concluded that the connections of the central nervous system were not predetermined, so that a nerve need not connect to any particular location to function correctly.
Sperry tested Weiss's research by surgically crossing the nerves that controlled the hind leg muscles of a rat. Under Weiss's theory, each nerve should eventually "learn" to control the leg muscle to which it was now connected. This did not happen. When the left hind foot was stimulated, the right foot responded instead. Sperry's experiments disproved Weiss's research and became thebasis of his doctoral dissertation, "Functional results of crossing nerves and transposing muscles in the fore and hind limbs of the rat." He received aPh.D. in zoology from the University of Chicago in 1941.
Sperry did other related experiments that confirmed his findings and furthercontradicted Weiss's theory that "function precedes form" (that is, the brainand nervous system learn, through experience, to function properly). From these and other experiments, Sperry deduced that genetic mechanisms determine some basic behavioral patterns. According to his theory, nerves have highly specific functions based on genetically predetermined differences in the concentration of chemicals inside the nerve cells.
In 1941, Sperry moved to the laboratory of the renowned psychologist Karl S.Lashley. A year later, Lashley became director of the Yerkes Laboratories ofPrimate Biology in Orange Park, Florida. Sperry joined him there on a Harvardbiology research fellowship. While there, he disproved some Gestalt psychology theories about brain mechanisms, as well as some theories of Lashley's.
After World War II, in 1946, Sperry accepted a position of assistant professor at the University of Chicago in the school's anatomy department. By 1954, he transferred to the California Institute of Technology (Caltech). At Caltech, Sperry conducted research on split-brain functions that he had first investigated when he worked at the Yerkes Laboratory. It had long been known that the cerebrum of the brain consists of two hemispheres. In most people the lefthemisphere controls the right side of the body and vice versa. The two halves are connected by a bundle of millions of nerve fibers called the corpus callosum, or the great cerebral commissure.
Neurosurgeons had discovered that this connection could be cut into with little or no noticeable change in the patient's mental abilities. After experiments on animals proved the procedure to be harmless, surgeons began cutting completely through the commissure of epileptic patients in an attempt to preventthe spread of epileptic seizures from one hemisphere to the other. The procedure was generally successful, and beginning in the late 1930s, cutting through the forebrain commissure became an accepted treatment method for severe epilepsy. Observations of the split-brain patients indicated no loss of communication between the two hemispheres of the brain.
From these observations, scientists assumed that the corpus callosum had no function other than as a prop to prevent the two hemispheres from sagging. Scientists also believed that the left hemisphere was dominant and performed higher cognitive functions such as speech. This theory developed from observations of patients whose left cerebral hemisphere had been injured; these patients suffered impairment of various cognitive functions, including speech. Sincethese functions were not transferred over to the uninjured right hemisphere,scientists assumed that the right hemisphere was less developed.
Sperry's work shattered these views. He and his colleagues at Caltech discovered that the corpus callosum is more than a physical prop; it provides a means of communication between the two halves of the brain and integrates the knowledge acquired by each of them. They also learned that in many ways, the right hemisphere is superior to the left. Although the left half of the brain issuperior in analytic, logical thought, the right half excels in intuitive processing of information. The right hemisphere also specializes in non-verbalfunctions, such as understanding music, interpreting visual patterns (such asrecognizing faces), and sorting sizes and shapes.
Sperry started published technical papers on his split-brain findings in thelate 1960s. The importance of his research was recognized relatively quickly,and in 1979 he was awarded the prestigious Albert Lasker Basic Medical Research Award, which included a $15,000 grant. The award was given in recognitionof the potential medical benefits of Sperry's research, including possible treatments for mental or psychosomatic illnesses.
In 1981, Sperry was honored with the Nobel Prize in physiology or medicine. He shared it with two other scientists, Torsten N. Wieseland David H. Hubel, for research on the central nervous system and the brain. In describing Sperry's work, the Nobel Prize selection committee praised the researcher for demonstrating the difference between the two hemispheres of the brain and for outlining some of the specialized functions of the right brain.