Facing facts about deliberate practice

Full text

GENERAL COMMENTARY
published: 17 July 2014
doi: 10.3389/fpsyg.2014.00751
Facing facts about deliberate practice
David Z. Hambrick1*, Erik M. Altmann1, Frederick L. Oswald2, Elizabeth J. Meinz 3and Fernand Gobet4
1Department of Psychology, Michigan State University, East Lansing, MI, USA
2Department of Psychology, Rice University, Houston, TX, USA
3Department of Psychology, Southern Illinois University Edwardsville, Edwardsville, IL, USA
4Institute of Psychology, Health, and Society, University of Liverpool, Liverpool, UK
*Correspondence: hambric3@msu.edu
Edited by:
Michael H. Connors, Macquarie University, Australia
Reviewed by:
Lena Rachel Quinto, Macquarie University, Australia
Michael H. Connors, Macquarie University, Australia
Keywords: deliberate practice, music, expertise, expert performance, individual differences, talent
A commentary on
The influence of deliberate practice on
musical achievement: a meta-analysis
by Platz, F., Kopiez, R., Lehmann, A. C., and
Wolf, A. (2014). Front. Psychol. 5:646. doi:
10.3389/fpsyg.2014.00646
More than 20 years ago, Ericsson and col-
leagues proposed that “individual differ-
ences in ultimate performance can largely
be accounted for by differential amounts
of past and current levels of practice”
(Ericsson et al., 1993, p. 392). We empir-
ically tested this claim through a meta-
analysis of studies of music and chess
(Hambrick et al., 2014). The claim was not
supported. Deliberate practice accounted
for about one-third of the reliable variance
in performance in each domain, leaving
most of the variance explainable by other
factors.
Focusing on music, Platz et al. (2014)
identified 13 studies of the relationship
between deliberate practice and perfor-
mance and found a correlation of 0.61
after correcting for unreliability. We credit
Platz et al. for their effort and thank them
for their criticisms of our meta-analysis.
However, none of these criticisms chal-
lenge our conclusion that deliberate prac-
tice is not as important as Ericsson and
colleagues have argued.
Platz et al.’s (2014) major criticism tar-
gets our conclusion that deliberate prac-
tice accounted for 30% of the variance
in music performance. They write that
“relationships between variables should be
interpreted in terms of linear relation-
ships” (p. 10), and that “it is incorrect
to interpret our findings (rc=0.61) as
evidence that DP explains 36% of the
variance in attained music performance”
(p. 11). They base this criticism on Hunter
and Schmidt’s (2004) argument that effect
sizes from meta-analyses (and primary
research) be reported as correlations rather
than estimates of variance accounted for
(i.e., rs rather than r2s).
Platz et al.’s (2014) criticism is puzzling
for two reasons. First, other researchers
have characterized the importance of
deliberate practice in terms of vari-
ance (individual differences) accounted
for—including not only Ericsson et al.
(1993), but also two authors of the Platz
et al. article (Reinhard Kopiez and Andreas
Lehmann). For example, Kopiez and col-
leagues concluded that “the total life prac-
tice time at the beginning of the study cor-
related moderately with the baseline per-
formance values and predicted only 17%
of their variance”(Jabusch et al., 2009,
p. 80, italics added; see also Lehmann
and Ericsson, 1996; Kopiez and Lee, 2006,
2008). Second, Hunter and Schmidt’s
(2004) point is not that r2is statistically
incorrect. Indeed, rand r2are both stan-
dard indexes of effect size (Cohen, 1988),
providing different ways to conceptual-
ize the strength of statistical relationships.
Rather, their point is that r2can make the-
oretically and practically important rela-
tionships seem trivially small—as when a
correlation of, say, 0.30 between a predic-
tor and an outcome is dismissed because
“only” 9% of the variance is explained.
For this reason, we reported both rand
r2values in our meta-analysis. Moreover,
to avoid trivializing the role of deliberate
practice,wehaverepeatedlyemphasized
its importance—the necessity of it for
becoming an expert. In no less a pub-
lic forum than the opinion pages of The
New York Times, two of us commented that
there is no denying the “power of practice”
(Hambrick and Meinz, 2011). Again, our
conclusion is not that deliberate practice
is unimportant, either statistically or the-
oretically;itisthatdeliberatepracticeis
not as important as Ericsson and colleagues
have argued,intheprecisesensethatfac-
tors other than deliberate practice account
for most of the variance in performance.
Platz et al. apparently miss this point.
Platz et al. (2014) also take aim at
the criteria we used for including a study
in our meta-analysis, calling them “intu-
itive” (p. 4). In fact, our criteria were dic-
tated by the theoretical claim we sought
to test and were clearly stated in our
article—measures of accumulated amount
of deliberate practice and performance
were collected and a correlation between
these measures was reported. Platz et al.
did find a few studies in their literature
search that we did not, but this does not
bear on our conclusion that deliberate
practice is not as important as Ericsson
and colleagues have argued. In fact, the
results of Platz et al.’s meta-analysis sup-
port this conclusion: A correlation of 0.61
between deliberate practice and music per-
formance leaves room for two additional
orthogonal predictors of nearly the same
magnitude (rs=0.56).
Perhaps with an inkling of this, Platz
et al. (2014) argue that their correlation
of 0.61 might be regarded as the “theo-
retically lower bound of the true effect of
www.frontiersin.org July 2014 | Volume 5 | Article 751 |1

Hambrick et al. Facing facts
DP” (p. 11) because “time estimations of
practice durations are only approximate
indicators of deliberate practice” (p. 11).
But their correlation could equally well
be regarded as an upper boundonthe
true effect of deliberate practice. For exam-
ple, using retrospective questionnaires to
measure deliberate practice could lead to
inflated correlations between deliberate
practice and performance if people base
practice estimates on their skill rather than
recollections of engaging in practice. The
more general problem with Platz et al.’s
argument is that it can always be made:
if the correlation between deliberate prac-
tice and performance is not as high as
one likes, one can always argue that this is
because the measure of deliberate practice
is imperfect—making it impossible to fal-
sify hypotheses about the predictive value
of deliberate practice.
Finally, some measures used by Platz
et al. (2014) may not be estimates of
deliberate practice. For example, for some
studies, they used the correlation between
number of accompanying performances
and sight-reading performance, but num-
berofaccompanyingperformancescould
be considered a measure of what Ericsson
et al. (1993) termed “work,” as distinct
from deliberate practice. Platz et al. are
also inconsistent in what they consider the
accumulation period for deliberate prac-
tice (e.g., lifetime for some studies, to age
18 for others).
The bottom line is that, in all major
domains in which deliberate practice has
been studied, most of the variance in per-
formance is explained by factors other
than deliberate practice (Macnamara et al.,
2014). These factors may include starting
age (Gobet and Campitelli, 2007), working
memory capacity (Meinz and Hambrick,
2010), and genes (Hambrick and Tucker-
Drob, 2014). For scientists, the task now
is to develop and test falsifiable theories
of expertise that include as many relevant
constructs as possible.
REFERENCES
Cohen, J. (1988). Statistical Power Analysis for
the Behavioral Sciences. Hillsdale, NJ: Lawrence
Erlbaum.
Ericsson, K. A., Krampe, R. T., and Tesch-Römer, C.
(1993). The role of deliberate practice in the acqui-
sition of expert performance. Psychol. Rev. 100,
363–406. doi: 10.1037/0033-295X.100.3.363
Gobet, F., and Campitelli, G. (2007). The role of
domain-specific practice, handedness, and start-
ing age in chess. Dev. Psychol. 43, 159–172. doi:
10.1037/0012-1649.43.1.159
Hambrick, D. Z., and Meinz, E. J. (2011). Sorry,
strivers: talent matters. The New York Times 12.
Hambrick, D. Z., Oswald, F. L., Altmann, E. M.,
Meinz, E. J., Gobet, F., and Campitelli, G.
(2014). Deliberate practice: is that all it takes
to become an expert? Intelligence 45, 34–45. doi:
10.1016/j.intell.2013.04.001
Hambrick, D. Z., and Tucker-Drob, E. (2014). The
genetics of music accomplishment: evidence for
gene-environment correlation and interaction.
Psychon. Bull. Rev. doi: 10.3758/s13423-014-0671-
9. [Epub ahead of print].
Hunter, J. E., and Schmidt, F. L. (2004). Methods
of Meta-Analysis: Correcting Error and Bias in
Research Findings. Thousand Oaks, CA: Sage.
Jabusch, H. C., Alpers, H., Kopiez, R., Vauth,
H., and Altenmuller, E. (2009). The influence
of practice on the development of motorskills
in pianists: a longitudinal study in a selected
motor task. Hum. Mov. Sci. 28, 74–84. doi:
10.1016/j.humov.2008.08.001
Kopiez, R., and Lee, J. I. (2006). Towards a
dynamic model of skills involved in sight
reading music. Music Educ. Res. 8, 97–120. doi:
10.1080/14613800600570785
Kopiez, R., and Lee, J. I. (2008). Towards a gen-
eral model of skills involved in sight read-
ing music. Music Educ. Res. 10, 41–62. doi:
10.1080/14613800701871363
Lehmann, A. C., and Ericsson, K. A. (1996).
Performance without preparation: structure and
acquisition of expert sight-reading and accom-
panying performance. Psychomusicology 15, 1–29.
doi: 10.1037/h0094082
Macnamara, B. N., Hambrick, D. Z., and Oswald, F.
L. (2014). Deliberate practice and performance in
music, games, sports, education, and professions:
a meta-analysis. Psychol. Sci. doi: 10.1177/09567
97614535810. [Epub ahead of print].
Meinz, E. J., and Hambrick, D. Z. (2010). Deliberate
practice is necessary but not sufficient to explain
individual differences in piano sight-reading
skill: the role of working memory capacity.
Psychol. Sci. 21, 914–919. doi: 10.1177/0956797610
373933
Platz, F., Kopiez, R., Lehmann, A. C., and Wolf,
A. (2014). The influence of deliberate prac-
tice on musical achievement: a meta-analysis.
Front. Psychol. 5:646. doi: 10.3389/fpsyg.2014.
00646
Conflict of Interest Statement: The authors declare
that the research was conducted in the absence of any
commercial or financial relationships that could be
construed as a potential conflict of interest.
Received: 20 June 2014; accepted: 27 June 2014;
published online: 17 July 2014.
Citation: Hambrick DZ, Altmann EM, Oswald FL,
Meinz EJ and Gobet F (2014) Facing facts about delib-
erate practice. Front. Psychol. 5:751. doi: 10.3389/fpsyg.
2014.00751
This article was submitted to Cognition, a section of the
journal Frontiers in Psychology.
Copyright © 2014 Hambrick, Altmann, Oswald,
Meinz and Gobet. This is an open-access article dis-
tributed under the terms of the Creative Commons
Attribution License (CC BY). The use, distribution or
reproduction in other forums is permitted, provided the
original author(s) or licensor are credited and that the
original publication in this journal is cited, in accor-
dance with accepted academic practice. No use, distribu-
tion or reproduction is permitted which does not comply
with these terms.
Frontiers in Psychology | Cognition July 2014 | Volume 5 | Article 751 |2