K. Anders Ericsson (born 1947) is a Swedish psychologist and Conradi Eminent Scholar and Professor of Psychology at Florida State University who is internationally recognized as a researcher in the psychological nature of expertise and human performance. Currently, Ericsson studies expert performance in domains such as medicine, music, chess, and sports, focusing exclusively on extended deliberate practice (e.g., high concentration practice beyond one's comfort zone) as a means of how expert performers acquire their superior performance. Critically, Ericsson's program of research serves as a direct complement to other research that addresses cognitive ability, personality, interests, and other factors that help researchers understand and predict deliberate practice and expert performance