Image source

Among investigators of expertise, it has generally been assumed that the performance of experts improved as a direct function of increases in their knowledge through training and extended experience.  However, recent studies show that there are, at least,  some domains where "experts" perform no better then less trained individuals (cf. outcomes of therapy by clinical psychologists, Dawes, 1994) and that sometimes experts’ decisions are no more accurate than beginners’ decisions and simple decision aids (Camerer & Johnson, 1991; Bolger & Wright, 1992). Most individuals who start as active professionals or as beginners in a domain change their behavior and increase their performance for a limited time until they reach an acceptable level. Beyond this point, however, further improvements appear to be unpredictable and the number of years of work and leisure experience in a domain is a poor predictor of attained performance (Ericsson & Lehmann, 1996). Hence, continued improvements (changes) in achievement are not automatic consequences of more experience and in those domains where performance consistently increases aspiring experts seek out particular kinds of experience, that is deliberate practice (Ericsson, Krampe & Tesch-Römer, 1993)-activities designed, typically by a teacher, for the sole purpose of effectively improving specific aspects of an individual’s performance.

.:psy.fsu.edu->