Arthur S. Reber was best known for his scientific research on unconscious learning, particularly that using an “artificial grammar” paradigm to examine how people acquire knowledge about the structure of a set of stimuli with little explicit awareness. His early work moved the field forward in important ways, eventually becoming widely adopted and generating tremendous interest in the cognitive unconscious. His later research ranged fearlessly over topics as diverse as implicit learning and tacit knowledge, the psychology of risk and gambling, the evolutionary origins of consciousness, and candidate biochemical mechanisms for the emergence of sentience.Don L. Scarborough attended Swarthmore College and the University of Pennsylvania, where he studied with Saul Sternberg and earned a Ph.D. in Cognitive Psychology in 1968. He was a Professor of Psychology at Brooklyn College of the City University of New York until his retirement in 2001, and was also on the faculty of the Computer Science department after receiving a degree in that field in 1985. Professor Scarborough’s primary research interests were word recognition processes and the perception of music.