Psychological Review Copyright 1993 by the American Psychological Association, Inc. 1993, Vol. 100. No. 3, 363-406 OO33-295X/93/S3.OO The Role of Deliberate Practice in the Acquisition of Expert Performance K. Anders Ericsson, Ralf Th. Krampe, and Clemens Tesch-Romer The theoretical framework presented in this article explains expert performance as the end result of individuals' prolonged efforts to improve performance while negotiating motivational and external constraints. In most domains of expertise, individuals begin in their childhood a regimen of effortful activities (deliberate practice) designed to optimize improvement. Individual differences, even among elite performers, are closely related to assessed amounts of deliberate practice. Many characteristics once believed to reflect innate talent are actually the result of intense practice extended for a minimum of 10 years. Analysis of expert performance provides unique evidence on the potential and limits of extreme environmental adaptation and learning. Our civilization has always recognized exceptional individ- because observed behavior is the result of interactions between uals, whose performance in sports, the arts, and science is environmental factors and genes during the extended period of vastly superior to that of the rest of the population. Specula- development. Therefore, to better understand expert and ex- tions on the causes of these individuals' extraordinary abilities ceptional performance, we must require that the account spec- and performance are as old as the first records of their achieve- ify the different environmental factors that could selectively ments. Early accounts commonly attribute these individuals' promote and facilitate the achievement of such performance. In outstanding performance to divine intervention, such as the addition, recent research on expert performance and expertise influence of the stars or organs in their bodies, or to special (Chi, Glaser, & Farr, 1988; Ericsson & Smith, 1991a) has shown gifts (Murray, 1989). As science progressed, these explanations that important characteristics of experts' superior performance became less acceptable. Contemporary accounts assert that the are acquired through experience and that the effect of practice characteristics responsible for exceptional performance are in- on performance is larger than earlier believed possible. For this nate and are genetically transmitted. reason, an account of exceptional performance must specify The simplicity of these accounts is attractive, but more is the environmental circumstances, such as the duration and needed. A truly scientific account of exceptional performance structure of activities, and necessary minimal biological attrib- must completely describe both the development leading to ex- utes that lead to the acquisition of such characteristics and a ceptional performance and the genetic and acquired character- corresponding level of performance. istics that mediate it. This account must specify the critical An account that explains how a majority of individuals can differences between exceptional and ordinary performers. It attain a given level of expert performance might seem inher- must also show that any postulated genetic differences can be ently unable to explain the exceptional performance of only a hereditary and are plausible from an evolutionary perspective. small number of individuals. However, if such an empirical Theoreticians in behavioral genetics (Plomin, DeFries, & account could be empirically supported, then the extreme McClearn, 1990) now argue that this is a very challenging task characteristics of experts could be viewed as having been ac- quired through learning and adaptation, and studies of expert performance could provide unique insights into the possibili- K. Anders Ericsson, Institute of Cognitive Science, University of ties and limits of change in cognitive capacities and bodily Colorado at Boulder; Ralf Th. Krampe and Clemens Tesch-Romer, Max Planck Institute for Human Development and Education, Berlin, functions. In this article we propose a theoretical framework Federal Republic of Germany. that explains expert performance in terms of acquired charac- The empirical research for this article was conducted at the Max teristics resulting from extended deliberate practice and that Planck Institute for Human Development in Berlin. Research support limits the role of innate (inherited) characteristics to general by the Max Planck Society and support and encouragement from Paul levels of activity and emotionality. We provide empirical sup- Baltes are gratefully acknowledged. port from two new studies and from already published evi- We thank Peter Usinger and Stefanie Heizmann for their help in the dence on expert performance in many different domains. data collection and Catherine Ashworth, Gregory Carey, Robert Crutcher, Janet Grassia, Reid Hastie, Stefanie Heizmann, Charles Judd, Ronald Kellogg, Robert Levin, Clayton Lewis, William Oliver, Brief Historical Background Peter Poison, Robert Rehder, Kurt Schlesinger, Vivian Schneider, and James Wilson for their valuable comments on earlier drafts of this Sir Francis Galton was the first scientist to investigate the article. Helpful suggestions and valuable criticism by Richard Shiffrin possibility that excellence in diverse fields and domains has a on previously submitted versions of this article are gratefully acknowl- common set of causes. He found that eminent individuals in edged. the British Isles were more likely to have close relatives who Correspondence concerning this article should be sent to K. Anders were also eminent—although not necessarily in the same do- Ericsson, who is now at the Department of Psychology R-54, Florida main—than to have distant relatives who were eminent. He State University, Tallahassee, Florida 32306-1051. concluded that eminence, that is, exceptional performance in a 364 K. ERICSSON, R. KRAMPE, AND C. TESCH-ROMER field, must be transmitted from parents to their offspring. Gal- the normal population. Greater height is an obvious advantage ton (1869/1979) argued that eminence was a virtually inevita- in basketball, high jumping, and most sports emphasizing ble consequence of inherited "natural ability," which was the strength. Shorter height is an advantage in gymnastics. Differ- conjunction of three types of elements: ences in height were found to discriminate well among male athletes of different events at the Olympic games in Montreal, By natural ability, I mean those qualities of intellect and disposi- tion, which urge and qualify a man to perform acts that lead to although the average height of all athletes did not differ from reputation. I do not mean capacity without zeal, nor zeal without that of a control group of students (Carter, Ross, Aubrey, Heb- capacity, nor even a combination of both of them, without an belinck, & Borms, 1982). Elite athletes also differ in the size of adequate power of doing a great deal of very laborious work. (p. their muscles, such as arm girth, and in the amount of fat mea- 37) sured by skin folds. Endurance athletes have a much higher If a man is gifted with vast intellectual ability, eagerness to work, and power of working, I cannot comprehend how such a aerobic ability, larger hearts, more capillaries supplying blood man should be repressed, (p. 39) to muscles, and a higher percentage of slow-twitch muscle fibers (Ericsson, 1990). Until quite recently researchers com- Galton readily acknowledged the importance of physiological monly believed that percentages of muscle fiber types and aer- exercises for improvement in motor performance and drew a obic power "are more than 90% determined by heredity for direct analogy to improvement of mental powers through study- males and females" (Brown & Mahoney, 1984, p. 609). Some ing and education. In his view, hereditary factors determine the researchers have therefore reasoned by analogy that basic gen- limit of the attainable performance for a given individual: eral characteristics of the nervous system, such as speed of So long as he is a novice, he perhaps flatters himself there is hardly neural transmission and memory capacities, have a genetic ori- an assignable limit to the education of his muscles; but the daily gin and cannot be changed through training and practice. gain is soon discovered to diminish, and at last it vanishes alto- Early efforts to find stable individual differences in neural gether. His maximum performance becomes a rigidly determin- transmission speed with simple response time (RT) and other ate quantity. (Galton, 1869/1979, p. 15) basic capacities were remarkably unsuccessful (Guilford, 1967). Binet (Varon, 1935) started out using tests of basic perceptual Even a hundred years later, Galton's conceptualization of emi- and cognitive capacities to measure IQ, but found large practice nent performance as reflecting a higher level of ultimate perfor- effects, which were later documented by Gibson (1969). Binet mance determined primarily by innate capacities (talent) is still eventually developed successful IQ tests derived from tests the modal view among people outside genetics and behavioral measuring comprehension, knowledge, and acquired skills. Be- genetics. Genetic influences are still incorrectly viewed as de- cause IQ reflects both environmental and genetic factors, re- terministic factors that lead to unmodifiable consequences de- cent research has challenged its interpretation and relation to termining the structure of the