Rosalie Rayner was an American psychologist best known for her work in behaviorism alongside her husband, John B. Watson. Born in 1899, she played a significant role in the famous Little Albert experiment, which demonstrated how emotions could be conditioned in humans. This study was pivotal in understanding the principles of classical conditioning. Rayner earned her Ph.D. from Columbia University and contributed to the field of psychology through her research and writings. She focused on child development and the application of behaviorist principles in education. Her work helped shape modern psychology, particularly in understanding learning and emotional responses.