Roger Sperry was an American neuropsychologist and biologist, best known for his research on the brain's lateralization. He conducted groundbreaking studies on patients who had undergone corpus callosotomy, a procedure that severs the connection between the brain's two hemispheres. His work revealed how each hemisphere specializes in different functions, leading to significant insights into brain organization and cognitive processes. In 1981, Sperry was awarded the Nobel Prize in Physiology or Medicine for his contributions to understanding the brain's structure and function. His research has had a lasting impact on fields such as neuroscience, psychology, and cognitive science, influencing how we understand human behavior and mental processes.