Daniel Simons is a cognitive psychologist known for his research on visual perception and attention. He is a professor at the University of Illinois and has contributed significantly to understanding how people perceive and process visual information. His work often explores the limitations of attention and how these limitations affect our everyday experiences. One of Simons' most famous studies is the Invisible Gorilla experiment, which demonstrates how people can miss significant visual events when their attention is focused elsewhere. This research has implications for various fields, including psychology, education, and advertising, highlighting the importance of awareness in our visual experiences.