K. Anders Ericsson

K. Anders Ericsson (23 October 1947 – 17 June 2020) was a Swedish psychologist and Conradi Eminent Scholar and Professor of Psychology at Florida State University who was internationally recognized as a researcher in the psychological nature of expertise and human performance.

Ericsson studied 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 served 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.

In a highly cited 1993 paper, Ericsson and colleagues conducted studies in which they concluded that expert violinists derived their talent not from innate abilities but rather from large amounts of deliberate practice over a period of 10 years or more. Canadian journalist Malcolm Gladwell drew upon Ericsson's research to establish his so-called 10,000 hour rule in the book ''Outliers.'' Ericsson later wrote that 'this rule...is wrong in several ways'. 10,000 was the average number of deliberate practice hours that the violinists had achieved by age 20, at which point the violinists 'were nowhere near masters'. Furthermore, the number of hours required to become an expert has been demonstrated to vary depending on field. In addition, Gladwell did not differentiate between deliberate practice and other forms of practice. Provided by Wikipedia