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 individuals, whose performance in sports, the arts, and science is vastly superior to that of the rest of the population. Speculations on the causes of these individuals' extraordinary abilities and performance are as old as the first records of their achievements. Early accounts commonly attribute these individuals' outstanding performance to divine intervention, such as the influence of the stars or organs in their bodies, or to special gifts (Murray, 1989). As science progressed, these explanations became less acceptable. Contemporary accounts assert that the characteristics responsible for exceptional performance are innate and are genetically transmitted.The simplicity of these accounts is attractive, but more is needed. A truly scientific account of exceptional performance must completely describe both the development leading to exceptional performance and the genetic and acquired characteristics that mediate it. This account must specify the critical differences between exceptional and ordinary performers. It must also show that any postulated genetic differences can be hereditary and are plausible from an evolutionary perspective. Theoreticians in behavioral genetics (Plomin, DeFries, & McClearn, 1990) We thank Peter Usinger and Stefanie Heizmann for their help in the 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, Peter Poison, Robert Rehder, Kurt Schlesinger, Vivian Schneider, and James Wilson for their valuable comments on earlier drafts of this article. Helpful suggestions and valuable criticism by Richard Shiffrin on previously submitted versions of this article are gratefully acknowledged.Correspondence concerning this article should be sent to K. Anders Ericsson, who is now at the Department of Psychology R-54, Florida State University, Tallahassee, Florida 32306-1051. because observed behavior is the result of interactions between environmental factors and genes during the extended period of development. Therefore, to better understand expert and exceptional performance, we must require that the account specify the different environmental factors that cou...