K. Anders Ericsson

Swedish-born American psychologist (Karl Anders Ericsson, 1947–2020). Conrad Professor of Psychology at Florida State University from 1992 until his death; before that, postdoctoral work at Carnegie Mellon with William G. Chase in the early 1970s, where the chess-expertise studies that began the modern expertise-research programme were carried out. Ericsson and Chase's 1973 demonstration that chess masters' memory for board positions did not extend to randomised positions — they remembered patterns, not pieces — set the empirical pattern for the field: study what experts can and cannot do, then ask what the difference rests on. Across the next four decades, Ericsson ran that programme across music, sport, chess, medicine, and professional work, and built it into the framework around deliberate practice.

Stake§

The stake was a single theoretical claim that Ericsson defended for the rest of his career: that expert performance is primarily built, not born, and the mechanism is the specific kind of practice he described in 1993. His reputation rose with the claim and would fall with it; he answered meta-analytic challenges to the claim's reach (Macnamara and colleagues, 2014 and 2016) in the journals through the late 2010s. He also acted as a public corrector of the Gladwell 10,000-hour reading of his work — repeatedly, in print and in interview — though the popular form of the idea outran the corrections.

Ericsson's 1993 Psychological Review paper with Ralf Krampe and Clemens Tesch-Römer established deliberate practice as a technical term and grounded it in a study of music students at the West Berlin Hochschule der Künste. The students were sorted by their professors into best, good, and teacher-track groups, their accumulated practice hours estimated through diaries and recall, and the resulting differences in practice volume across groups — pronounced and consistent — supplied the empirical case for the claim that expert performance differs by what people had done in practice, not by what they had been born with.

The trade book Peak: Secrets from the New Science of Expertise, co-written with Robert Pool in 2016, is the popular-facing restatement of the same case across the intervening twenty-three years of follow-up work — chess (with Neil Charness), medical diagnosis (with Lisa Tetzlaff), sport (with several collaborators), and the integrating Cambridge Handbook of Expertise and Expert Performance, which Ericsson co-edited across two editions (2006 and 2018). Peak is also Ericsson's clearest public attempt to detach the deliberate-practice framework from the Gladwell 10,000-hour reading: the figure was a population mean for one elite group of violinists at one moment in their career, not a universal threshold; he says so repeatedly across the book.

Opposition to Ericsson's strong claim has come from two directions. The first is the transfer literature — Detterman and Sternberg's edited volume appearing in the same year as the deliberate-practice paper — arguing that skilled performance acquired in one task transfers only narrowly to neighbouring tasks. The second is the meta-analytic strand of the 2010s (Macnamara et al., 2014, 2016) showing that accumulated deliberate practice accounts for around a quarter of variance in performance, with the share much smaller in less-structured domains. Ericsson answered both lines in the journals — arguing the meta-analyses were including non-deliberate practice in their counts, and that transfer is precisely what the deliberate-practice framework predicts to be limited — but the disagreement remains active in the literature.

Ericsson died of complications following a stroke in Tallahassee, Florida, on 17 June 2020.