Roger Wolcott Sperry facts for kids
Quick facts for kids
Roger Sperry
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Roger Wolcott Sperry
August 20, 1913 Hartford, Connecticut, U.S.
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| Died | April 17, 1994 (aged 80) Pasadena, California, U.S.
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| Awards | Nobel Prize in Physiology or Medicine (1981) |
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| Fields | Neuropsychology |
| Thesis | Functional results of crossing nerves and transposing muscles in the fore and hind limbs of the rat (1941) |
| Doctoral advisor | Paul A. Weiss |
Roger Wolcott Sperry (August 20, 1913 – April 17, 1994) was an American scientist who studied the brain. He was a neuropsychologist, a neurobiologist, and a cognitive neuroscientist. He won the 1981 Nobel Prize in Physiology or Medicine for his important work on how the two halves of the brain work. This research is often called "split-brain" research. A study in 2002 showed that Sperry was one of the most often mentioned psychologists of the 20th century.
Contents
Early Life and Education
Roger Sperry was born in Hartford, Connecticut. His father worked in banking, and his mother had studied business. Roger grew up in a family that valued doing well in school. He had one brother, Russell. When Roger was 11, his father passed away. After that, his mother became an assistant at the local high school.
Roger went to Hall High School in West Hartford, Connecticut. He was a great athlete in many sports and did well enough in his studies to get a scholarship to Oberlin College. At Oberlin, he was the captain of the basketball team. He also played baseball, football, and ran track. He worked at a campus cafe to help pay for his education.
Sperry first studied English, but an introductory psychology class changed his path. This class was taught by Professor R. H. Stetson, who had worked with William James, known as the "father of American Psychology." This class made Sperry very interested in the brain and how it can change. Sperry often helped Professor Stetson, who had difficulty moving around, by driving him to meetings and lunches. Sperry would listen to Stetson and his colleagues talk about their research. This made him even more interested in psychology. After getting his bachelor's degree in English in 1935, he stayed at Oberlin to earn a master's degree in psychology in 1937.
He later earned his Ph.D. in zoology from the University of Chicago in 1941. His supervisor was Paul A. Weiss. After his Ph.D., Sperry did more research with Karl Lashley at Harvard University. He spent most of this time at the Yerkes Primate Research Center in Orange Park, Florida.
Understanding the Brain: Sperry's Research Journey
In 1942, Sperry started working at the Yerkes Laboratories of Primate Biology. Here, he focused on experiments that involved changing how motor and sensory nerves were connected. He left in 1946 to become a professor at the University of Chicago.
In 1949, doctors found signs of tuberculosis during a check-up. He went to Saranac Lake in New York for treatment. During this time, he began writing down his ideas about the mind and brain. His first ideas were published in a science magazine in 1952. Later that year, he became a section chief at the National Institutes of Health. In 1954, he accepted a job as a professor at the California Institute of Technology (Caltech). This is where he did his most famous experiments with Dr. Joseph Bogen and his students, including Michael Gazzaniga.
How Nerves Connect: The Chemoaffinity Hypothesis
While studying for his Ph.D., Sperry became very interested in how specific neurons (brain cells) connect and how brain circuits are formed. He wondered if our abilities are mostly "nature" (what we are born with) or "nurture" (what we learn). He started experiments to find answers.
In one experiment, Sperry rewired the motor nerves in rats' legs. This meant the nerve that usually controlled the left leg now controlled the right leg, and vice versa. He placed the rats in a cage with an electric floor divided into four sections. When a rat's left back leg was shocked, it would lift its right paw instead of the left. Sperry wanted to see how long it would take the rats to learn to lift the correct paw. After many tries, the rats never learned to lift the right paw. This led Sperry to believe that some connections in the brain are "hardwired" and cannot be easily changed by learning. He said, "no adaptive functioning of the nervous system took place."
Sperry continued his work on nerve connections with salamanders. He cut their optic nerves (which connect the eyes to the brain) and rotated their eyes 180 degrees. He wanted to know if their vision would return to normal after the nerves grew back. If the nerves grew back to their original spots, the salamanders would see the world upside down and reversed. If the nerves found new spots, their vision would be normal. The salamanders continued to see the world upside down and reversed. No amount of training could change this. These studies strongly suggested that nerves are guided back to their correct places by "intricate chemical codes under genetic control." This idea became known as Sperry's chemoaffinity hypothesis in 1951.
Sperry later became a professor emeritus at Caltech. The Sperry Neuroscience Building at Oberlin College was named in his honor in 1990.
Nobel Prize and Split-Brain Discoveries
Sperry received many awards during his life. These included the California Scientist of the Year Award in 1972, the National Medal of Science in 1989, and the Wolf Prize in Medicine in 1979. He also won the Albert Lasker Medical Research Award in 1979. In 1981, he shared the Nobel Prize in Physiology or Medicine with David H. Hubel and Torsten N. Wiesel. He won this award for his work with "split-brain" patients.
Understanding the Brain's Two Halves
The brain is divided into two main parts, called hemispheres: the left and the right. These two halves are connected in the middle by a thick band of nerve fibers called the corpus callosum. In some patients who suffered from severe epilepsy (a disease that causes intense seizures), doctors would cut the corpus callosum. This surgery prevented seizures from spreading from one side of the brain to the other, which helped patients live more normal lives.
Sperry became interested in "split-brain" research while studying how learning transfers between the eyes. For example, if you learn to solve a puzzle with one eye covered, you usually know how to solve it with the other eye. Sperry wondered how this transfer happened.
He did an experiment with cats. He cut the nerves in their eyes so the left eye connected only to the left brain, and the right eye connected only to the right brain. He also cut their corpus callosum. The cats were taught to tell the difference between a triangle and a square using only their right eye (with the left eye covered). When their left eye was uncovered, they had no idea what they had just learned. They could then be taught to tell the difference between a square and a triangle with the left eye. This showed that the left and right hemispheres learned and remembered different things when they were not connected. Sperry believed this meant the two hemispheres worked separately without the corpus callosum.
Sperry's research with cats helped doctors understand that cutting the corpus callosum could be a very effective treatment for epilepsy. After the surgery, patients seemed to behave normally. This made scientists wonder: if the surgery had no effect on daily life, what was the purpose of the corpus callosum? Was it just there to keep the two sides of the brain from collapsing, as one scientist jokingly asked? Sperry was asked to create tests to see if the surgery truly caused any changes in the patients' abilities.
Experiments with Split-Brain Patients
Working with his student Michael Gazzaniga, Sperry asked several "split-brain" patients to take part in his study. These tests looked at the patients' language, vision, and motor skills. When a person sees something in their left visual field (on their left side), that information goes to the right side of their brain. Information from the right visual field goes to the left side of the brain.
In one test, Sperry showed a word to either the left or right visual field for a very short time. If the word was shown to the right visual field (processed by the left brain), the patient could say what the word was. But if the word was shown to the left visual field (processed by the right brain), the patient could not say the word. This made Sperry think that only the left side of the brain could speak.
However, in another experiment, Sperry found that the right brain does have some language skills. He had patients put their left hands into a tray of objects they couldn't see. Then, a word was shown to their left visual field (processed by the right brain). This word described one of the objects in the tray. The patient's left hand would then pick up the correct object. When asked about the word and the object, the patients said they hadn't seen the word and didn't know why they were holding the object. The right side of the brain had understood the word and told the left hand to pick it up. But because the right brain cannot speak, and the left brain hadn't seen the word, the patient couldn't explain what had happened.
In another test, Sperry showed one object to the left visual field and a different object to the right visual field. The patient's left hand was placed under a screen. They were asked to draw what they had seen with their left hand. Patients would draw what they had seen in their left visual field. But when asked what they had drawn, they would describe what had been shown to their right visual field.
These tests proved that when the corpus callosum is cut, the two brain halves cannot communicate. They don't even know the other half exists. Some patients even reported strange things outside the lab. For example, "while their left hand was unbuttoning their shirt, the right hand would follow along behind and button it again." These experiments greatly helped us understand how different parts of the brain have different jobs.
Sperry's research greatly improved our understanding of the lateralization of brain function (how different brain sides do different things). In 1989, he also received the National Medal of Science. In 1993, he received the Lifetime Achievement Award from the American Psychological Association.
Personal Life
In 1949, Sperry married Norma Gay Deupree. They had a son, Glenn Michael, and a daughter, Janeth Hope. Sperry was a quiet, thoughtful, and humble man who was always curious. He continued to work, question, and learn until he passed away in 1994 from ALS, also known as Lou Gehrig's Disease. Sperry often sat in his office with his feet on his desk, writing in his notebook or deep in thought.
Sperry loved paleontology (the study of fossils) and had a large collection of fossils in his home. He was also a very talented sculptor, artist, and ceramicist. He enjoyed camping and fishing trips with his wife and children in Baja, California.
Images for kids
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A robot, symbolizing the brain's complex functions.
