Gritting One's way to success - Grit explains skill in elite youth soccer players beyond (deliberate) practice

Practice is one of the most important predictors of skill. To become an expert, performers must engage in practice for a prolonged time to develop the psychological characteristics necessary for outstanding performance. Deliberate practice (DP), that is focused repetitive activities with corrective feedback, is particularly beneficial for skill development. The amount of accumulated DP differentiates experts and novices. However, the predictive strength of DP weakens considerably when it comes to differentiating between differently skilled experts, leaving a way clear for other non-practice related factors to exercise their influence. In this paper, we demonstrate using a large sample (388) of elite youth soccer players that one such factor, the personality trait of grit, predicts expertise level both directly and indirectly. Grittier players accumulated more time in coach-led team practice, the activity, which is arguably closest to DP in team sports, which in turn predicted the skill level. Other practice activities, such as self-led training or playing with peers, were not predictive of skill level, neither were they influenced by grit. Grit, however, continued to exert a direct positive influence on the skill level of players even after accounting for the hours of DP accumulated. Overall, a standard deviation of change in the grit score resulted in at least a third of standard deviation improvement in skill. Our findings highlight the need for the inclusion of additional factors in theoretical frameworks in situations where the predictive power of traditional expertise factors, such as practice, is limited.

Given that the detailed original criteria for deliberate practice have not changed, could the understanding of this complex concept have improved over time? A response to Macnamara and Hambrick (2020)

In their commentary, Macnamara and Hambrick (Psychol Res, 2017) accused my colleagues and me of systematically changing the definition of the concept of deliberate practice. Deliberate practice was the result of a search for characteristics of effective practice in the laboratory that was shown to improve expert professional performance in domains, such as music. In this reply, I will first describe five different criteria that defined the original concept of deliberate practice and each of them is presented with directly supporting quotes from Ericsson, Krampe, and Tesch-Römer (Psychol Rev 100:396–406, 10.1037/0033-295X.87.3.215, 1993) paper. Unfortunately, Macnamara, Hambrick, and Oswald (Psychol Sci 25:1608–1618, 10.1177/0956797614535810, 2014) misinterpreted our concept of deliberate practice, and defined it much more broadly: “as engagement in structured activities created specifically to improve performance in a domain” (p. 914). This definition led them to include activities, such as attending lectures, studying alone by students, and group activities led by a coach, where each activity does not meet one or more of our criteria for deliberate practice. In this commentary, I will argue that Macnamara and Hambrick (2020) became aware of some of the original criteria for deliberate practice, such as the role of individualized training by a teacher, and these discoveries misled them to assume that we had changed our definition. The intended meaning of sentences that Macnamara and Hambrick (2020) had carefully selected is shown to have an appropriate interpretation in Standard English that is consistent with our original definition of deliberate practice. In conclusion, I will give a proposal for how the different perspectives can be reconciled.

Deliberate Practice and Proposed Limits on the Effects of Practice on the Acquisition of Expert Performance: Why the Original Definition Matters and Recommendations for Future Research

Over 25 years ago Ericsson et al. (1993) published the results of their search for the most effective forms of training in music, a domain where knowledge of effective training has been accumulated over centuries. At music academies master teachers provide students individualized instruction and help them identify goals and methods for their practice sessions between meetings - this form of solitary practice was named deliberate practice, and its accumulated duration during development was found to distinguish groups with differing levels of attained music performance. In an influential meta-analysis Macnamara et al. (2014) identified studies that had collected estimates of practice accumulated during development and attained performance and reported that individual differences in deliberate practice accounted for only 14% of variance in performance. Their definition of "deliberate practice" differs significantly from the original definition of deliberate practice and will henceforth be referred to as structured practice. We explicate three criteria for reproducible performance and purposeful/deliberate practice and exclude all effect sizes considered by Macnamara et al. (2014) that were based on data not meeting these criteria. A reanalysis of the remaining effects estimated that accumulated duration of practice explained considerably more variance in performance (29 and 61% after attenuation correction). We also address the argument that the limited amount of variance explained by the duration of practice necessarily implies an important role of genetic factors, and we report that genetic effects have so far accounted for remarkably small amounts of variance - with exception of genetic influences of height and body size. The paper concludes with recommendations for how future research on purposeful and deliberate practice can go beyond recording only the duration of practice to measuring the quality of practice involving concentration, analysis, and problem solving to identify conditions for the most effective forms of training.