Richard Atkinson is a prominent American psychologist known for his contributions to the field of cognitive psychology. He is best recognized for developing the Atkinson-Shiffrin model, which describes how information is processed in the human memory system. This model outlines three key stages: sensory memory, short-term memory, and long-term memory. In addition to his work on memory, Atkinson has also made significant contributions to educational psychology. He served as the president of the University of California system and has been involved in various research initiatives aimed at improving learning and teaching methods in educational settings.