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Expert Performance: Its Structure and Acquisition

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Expert Performance: Its Structure and Acquisition

Abstract

Counter to the common belief that expert performance reflects innate abilities and capacities, recent research in different domains of expertise has shown that expert performance is predominantly mediated by acquired complex skills and physiological adaptations. For elite performers, supervised practice starts at very young ages and is maintained at high daily levels for more than a decade. The effects of extended deliberate practice are more far-reaching than is commonly believed. Performers can acquire skills that circumvent basic limits on working memory capacity and sequential processing. Deliberate practice can also lead to anatomical changes resulting from adaptations to intense physical activity. The study of expert performance has important implications for our understanding of the structure and limits of human adaptation and optimal learning. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Science Watch
Expert Performance
Its Structure and Acquisition
K. Anders Ericsson
and
Neil Chamess
Counter
to the
common belief that expert performance
reflects innate abilities
and
capacities, recent research
in
different domains of expertise
has
shown that expert per-
formance
is
predominantly mediated
by
acquired complex
skills and physiological adaptations. For elite performers,
supervised practice starts
at
very young ages
and
is main-
tained
at
high daily
levels
for
more than
a
decade.
The
effects of extended deliberate practice are more far-reach-
ing than
is
commonly believed. Performers
can
acquire
skills that circumvent basic limits
on
working memory
capacity
and
sequential processing. Deliberate practice
can also lead
to
anatomical changes resulting from
ad-
aptations
to
intense physical activity.
The
study of expert
performance
has
important implications
for our
under-
standing of the structure
and
limits of human adaptation
and optimal learning.
In nearly every field of human endeavor, the performance
of
the
best practitioners
is so
outstanding,
so
superior
even
to the
performance
of
other highly experienced
in-
dividuals
in the
field, that most people believe
a
unique,
qualitative attribute, commonly called innate talent, must
be invoked
to
account
for
this highest level
of
perfor-
mance. Although these differences
in
performance are
by
far
the
largest psychologists have been able
to
reliably
measure among healthy adults, exceptional performance
has
not,
until recently, been extensively studied
by sci-
entists.
In
the
last decade, interest
in
outstanding
and ex-
ceptional achievements
and
performance
has
increased
dramatically. Many books have been recently published
on
the
topic
of
genius
(for
example, Gardner, 1993a;
Murray, 1989a; Simonton,
1984,
1988b; Weisberg,
1986,
1993),
exceptionally creative individuals
(D. B.
Wallace
& Gruber, 1989), prodigies (Feldman, 1986;
A.
Wallace,
1986),
and
exceptional performance
and
performers
(Howe, 1990;Radford, 1990; Smith, 1983). Of particular
interest
to the
general public
has
been
the
remarkable
ability
of
idiot savants
or
savants,
who in
spite
of a
very
low general intellectual functioning display superior
per-
formance
in
specific tasks
and
domains, such
as
mental
multiplication
and
recall
of
music (Howe, 1990; Treffert,
1989).
The
pioneering research comparing
the
perfor-
mance
of
experts
and
beginners (novices)
by de
Groot
(1946/1978)
and
Chase
and
Simon (1973) has generated
a great deal
of
research
(Chi,
Glaser,
&
Farr, 1988;
Er-
icsson
&
Smith, 1991b).
A
parallel development
in com-
puter science
has
sought
to
extract
the
knowledge
of
ex-
perts
by
interviews (Hoffman, 1992)
to
build expert sys-
tems,
which
are
computer models that
are
designed
to
duplicate the performance of these experts
and
make their
expertise generally available. These efforts
at
artificial
in-
telligence have been most successful
in
domains that have
established symbolic representations, such
as
mathemat-
ical calculation, chess,
and
music (Barr
&
Feigenbaum,
1981-1982: Cohen
&
Feigenbaum, 1982), which inci-
dentally
are the
main domains
in
which prodigies
and
savants have been able
to
display clearly superior perfor-
mance (Feldman,
1980,
1986).1
The recent advances
in our
understanding of excep-
tional performance have
had
little impact
on
general the-
ories
in
psychology.
The new
knowledge
has not
fulfilled
the humanistic goals
of
gaining insights from
the
lives
of
outstanding people about how people might improve their
lives.
Maslow (1971) long ago eloquently expressed these
goals:
If we want
to
know how fast
a
human being can run, then
it is
no use
to
average
out
the speed of
a
"good sample" of the pop-
Lyle
E.
Bourne served
as
action editor
for
this article.
K. Anders Ericsson, Department of Psychology, Florida State
Uni-
versity; Neil Charness, Department of Psychology, University of Waterloo,
Waterloo, Ontario, Canada (now
at
Department
of
Psychology, Florida
State University).
We wish
to
thank Janet Grassia, Andreas Lehmann, William Oliver,
and Michael Rashotte
for
their valuable comments
on
drafts
of
this
article.
Correspondence concerning this article should
be
addressed
to K.
Anders Ericsson, Department
of
Psychology, Florida State University,
Tallahassee,
FL
32306-1051.
1
The
field
of
visual
art may
offer
at
least
one
recent exception
(Feldman, 1986).
The
Chinese girl Yani produced some acclaimed
paintings between
the
ages
of
three
and six
(Ho, 1989),
but
matters
are
complicated
by the
fact that these paintings were selected
by her
father
(a professional painter) from more than 4,000 paintings completed
by
Yani during this three-year period (Feng, 1984).
August
1994
American Psychologist
Copyright 1994
by
the American Psychological Association,
Inc.
0003-066X/94/$2.00
Vol.
49,
No. 8,
725-747
725
ulation; it is far better to collect Olympic gold medal winners
and see how
well
they can
do.
If
we
want to know the possibilities
for spiritual growth, value growth, or moral development in
human beings, then
I
maintain that
we
can learn most by study-
ing our moral, ethical, or saintly people. . .
.
Even when "good
specimens," the saints and sages and great leaders of history,
have been available for study, the temptation too often has
been to consider them not human but supernaturally en-
dowed, (p. 7)
The reasons for the lack of impact become clear when
we consider the two most dominant approaches and their
respective goals. The human information-processing ap-
proach, or the skills approach, has attempted to explain
exceptional performance in terms of knowledge and skills
acquired through experience. This approach, originally
developed by Newell and Simon (1972), has tried to show
that the basic information-processing system with its el-
ementary information processes and basic capacities re-
mains intact during skill acquisition and that outstanding
performance results from incremental increases in
knowledge and skill due to the extended effects of expe-
rience. By constraining the changes to acquired knowledge
and skill, this approach has been able to account for ex-
ceptional performance within existing general theories of
human cognition. According to this approach the mech-
anisms identified in laboratory studies of learning can be
extrapolated to account for expertise and expert perfor-
mance by an incremental accumulation of knowledge and
skill over a decade of intense experience in the domain.
The long duration of the necessary period of experience
and the presumed vast complexity of the accumulated
knowledge has discouraged investigators from empirically
studying the acquisition of expert performance. Similarly,
individual differences in expert performance, when the
amount of experience is controlled, have not been of ma-
jor interest and have been typically assumed to reflect
differences in the original structure of basic processes,
capacities, and abilities.
The other major approach focuses on the individual
differences of exceptional performers that would allow
them to succeed in a specific domain. One of the most
influential representatives of this approach is Howard
Gardner, who in 1983 presented his theory of multiple
intelligence in his book Frames of
Mind:
The Theory of
Multiple Intelligences (hereinafter referred to as Frames
of
Mind).
Gardner
(1983,
1993a, 1993b) drew on the re-
cent advances in biology and brain physiology about
neural mechanisms and localization of brain activity to
propose an account of the achievements of savants, prod-
igies,
and geniuses in specific domains. He argued that
exceptional performance results from a close match be-
tween the individual's intelligence profile and the de-
mands of the particular domain. A major concern in this
approach is the early identification and nurturing of chil-
dren with high levels of the required intelligence for a
specific domain. Findings within this approach have lim-
ited implications for the lives of the vast majority of chil-
dren and adults of average abilities and talents.
In this article we propose a different approach to
the study of exceptional performance and achievement,
which we refer to as the study of expert performance.
Drawing on our earlier published research, we focus on
reproducible, empirical phenomena of superior perfor-
mance. We will thus not seriously consider anecdotes or
unique events, including major artistic and scientific in-
novations, because they cannot be repeatedly reproduced
on demand and hence fall outside the class of phenomena
that can be studied by experimental methods. Our ap-
proach involves the identification of reproducible superior
performance in the everyday life of exceptional performers
and the capture of this performance under laboratory
conditions. Later we show that the analysis of captured
superior performance reveals that extended training alters
the cognitive and physiological processes of experts to a
greater degree than is commonly believed possible. In the
final section of the article we review results from studying
the lives of expert performers and identify the central role
of large amounts of focused training (deliberate practice),
which we distinguish from other forms of experience in
a domain. The recent evidence for far-reaching effects of
training leads us to start by reexamining the available
evidence for innate talent and specific gifts as necessary
conditions for attaining the highest levels of performance
in a domain.
Traditional View of the Role of Talent
in Exceptional Performance
Since the emergence of civilization, philosophers have
speculated about the origin of highly desirable individual
attributes, such as poetic ability, physical beauty, strength,
wisdom, and skill in handiwork (Murray, 1989b). It was
generally believed that these attributes were gifts from the
gods,
and it was commonly recognized that "On the whole
the gods do not bestow more than one gift on a person"
(Murray, 1989b, p. 11). This view persisted in early Greek
thought, although direct divine intervention was replaced
by natural causes. Ever since, there has been a bias toward
attributing high abilities to gifts rather than experience,
as expressed by John Stuart Mill, there is "a common
tendency among mankind to consider all power which is
not visibly the effect of practice, all skill which is not
capable of being reduced to mechanical rules, as the result
of a particular gift" (quoted in Murray, 1989b, p. 12).
One important reason for this bias in attribution,
we believe, is linked to immediate legitimatization of var-
ious activities associated with the gifts. If the gods have
bestowed a child with a special gift in a given art form,
who would dare to oppose its development, and who
would not facilitate its expression so everyone could enjoy
its wonderful creations? This argument may appear
strange today, but before the French Revolution the priv-
ileged status of kings and nobility and the birthright of
their children were primarily based on such claims.
The first systematic development of this argument
for gaining social recognition to artists can be found in
classic work on The Lives of the Artist by Vasari (Bull,
1987),
originally published in 1568. This book provided
726August 1994 American Psychologist
the first major biography of artists and is generally rec-
ognized as a major indirect influence on the layman's
conceptions of artists even today (Barolsky, 1991). Al-
though Vasari's expressed goal was simply to provide a
factual history of art, modern scholars argue that "the
Lives were partly designed to propagate ideas of the artist
as someone providentially born with a vocation from
heaven, entitled to high recognition, remuneration and
respect" (Bull, 1987, Vol. 2, p. xxvi). To support his claim,
Vasari tried to identify early signs of talent and ability in
the lives of the artists he described. When facts were miss-
ing, he is now known to have added or distorted material
(Barolsky, 1991). For example, Vasari dated his own first
public demonstration of high ability to the age of 9, al-
though historians now know that he was 13 years old at
that event (Boase, 1979). His evaluations of specific pieces
of art expresssed his beliefs in divine gifts. Michelangelo's
famous painting in the Sistine Chapel, the Final Judg-
ment, was described by Vasari as "the great example sent
by God to men so that they can perceive what can be
done when intellects of the highest grade descend upon
the earth" (quoted in Boase, 1979, pp. 251-252). Vasari
also tried to establish a link between the noble families
and the families of outstanding artists by tracing the her-
itage and family trees of the artists of his time to the great
families of antiquity and to earlier great artists. However,
much of the reported evidence is now considered to have
been invented by Vasari (Barolsky, 1992). In the centuries
following Vasari, our civilization underwent major social
changes leading to a greater social mobility through the
development of a skilled middle class and major progress
in the accumulation of scientific knowledge. It became
increasingly clear that individuals could dramatically in-
crease their performance though education and training,
if they had the necessary drive and motivation. Specu-
lation on the nature of talent started to distinguish
achievements due to innate gifts from other achievements
resulting from learning and training. In 1759 Edward
Young published a famous book on the origin of creative
products, in which he argued that "An Original may be
said to be of vegetable nature: it rises spontaneously from
the vital root of Genius; it
grows,
it is not made" (quoted
with original italics in Murray, 1989b, p. 28). Hence, an
important characteristic of genius and talent was the ap-
parent absence of learning and training, and thus talent
and acquired skill became opposites (Bate, 1989). A cen-
tury later Galton (1869/1979) presented a comprehensive
scientific theory integrating talent and training that has
continued to influence the conception of exceptional per-
formance among the general population.
Sir Francis Galton was the first scientist to investigate
empirically the possibility that excellence in diverse fields
and domains has a common set of causes. On the basis
of an analysis of eminent men in a wide range of domains
and of their relatives, Galton (1869/1979) argued that
three factors had to be present: innate ability, eagerness
to work, and "an adequate power of doing a great deal
of very laborious work" (p. 37). Because the importance
of the last two factors—motivation and effort—had al-
ready been recognized (Ericsson, Krampe, & Heizmann,
1993),
later investigators concentrated primarily on
showing that innate abilities and capacities are necessary
to attain the highest levels of performance.
Galton (1869/1979) acknowledged a necessary but
not sufficient role for instruction and practice in achieving
exceptional performance. According to this view, perfor-
mance increases monotonically as a function of practice
toward an asymptote representing a fixed upper bound
on performance. Like Galton, contemporary researchers
generally assume that training can affect some of the
components mediating performance but cannot affect
others. If performance achieved after extensive training
is limited by components that cannot be modified, it is
reasonable to assert that stable, genetically determined
factors determine the ultimate level of performance. If
all possible changes in performance related to training
are attained after a fairly limited period of practice, this
argument logically implies that individual differences in
final performance must reflect innate talents and natural
abilities.
The view that talent or giftedness for a given activity
is necessary to attain the highest levels of performance
in that activity is widely held among people in general.
This view is particularly dominant in such domains of
expertise as chess, sports, music, and visual arts, where
millions of individuals are active but only a very small
number reach the highest levels of performance.
One of the most prominent and influential scientists
who draw on evidence from exceptional performance of
artists, scientists, and athletes for a biological theory of
talent is Howard Gardner. In Frames of
Mind,
Gardner
(1983) proposed seven intelligences: linguistic, musical,
spatial, logical-mathematical, bodily kinesthetic, and in-
terpersonal and intrapersonal intelligence—each an in-
dependent system with its own biological bases (p. 68).
This theory is a refinement and development of ideas
expressed in an earlier book (Gardner, 1973), in which
the talent position was more explicitly articulated, es-
pecially in the case of
music.
Gardner (1973) wrote,
Further evidence of the strong hereditary basis of musical talent
comes from a number of
sources.
Most outstanding musicians
are discovered at an early age, usually before 6 and often as
early as 2 or 3, even in households where relatively little music
is
heard.
Individual differences
are
tremendous among children,
and training seems to have comparatively little effect in reducing
these differences, (p. 188)
He discussed possible mechanisms for talent in the con-
text of music savants, who in spite of low intellectual
functioning display impressive music ability as children:
"it seems possible that the children are reflecting a
rhythmic and melodic capacity that is primarily heredi-
tary, and which needs as little external stimulation as does
walking and talking in the normal child" (Gardner, 1973,
p.
189). Although Gardner (1983) did not explicitly dis-
cuss his earlier positions, the evidence from prodigies and
savants remains central. Frames of Mind contains a care-
ful review of the then available research on the dramatic
August 1994 American Psychologist727
effects of training on performance. In particular, he re-
viewed the exceptional music performance of young chil-
dren trained with the Suzuki method and noted that many
of these children who began training without previous
signs of musical talent attained levels comparable to music
prodigies of earlier times and gained access to the best
music teachers in the world. The salient aspect of talent,
according to Gardner (1983), is no longer the innate
structure (gift) but rather the potential for achievement
and the capacity to rapidly learn material relevant to one
of the intelligences. Gardner's (1983) view is consistent
with Suzuki's rejection of inborn talent in music and Su-
zuki's (1963/1981) early belief in individual differences
in innate general ability to learn, although Suzuki's innate
abilities were not specific to a particular domain, such as
music. However, in his later writings, Suzuki (1980/1981)
argued that "every child can be highly educated if he is
given the proper training" (p. 233), and he blamed earlier
training failures on incorrect training methods and their
inability to induce enthusiasm and motivation in the
children. The clearest explication of Gardner's (1983)
view is found when he discussed his proposal for empirical
assessments of individuals' profiles in terms of the seven
intelligences. He proposed a test in which "individuals
were given the opportunity to learn to recognize certain
patterns [relevant to the particular domain] and were
tested on their capacities to remember these from one
day to the next" (p. 385). On the basis of tests for each
of the intelligences, "intellectual profiles could be drawn
up in the first year or two of
life"
(p.
386), although reliable
assessments may have to wait until the preschool years
because of "early neural and functional plasticity" (p.
386).
Gardner's own hunch about strong intellectual
abilities was that "an individual so blessed does not merely
have an easy time learning new patterns; he learns them
so readily that // is virtually impossible for him to forget
them"
(pp. 385-386).
Our reading of Gardner's (1993a, 1993b)2 most re-
cent books leads us to conclude that his ideas on talent
have not fundamentally changed. According to Gardner's
(1983) influential view, the evidence for the talent view
is based on two major sources of data on performance:
the performance of prodigies and savants and the ability
to predict future success of individuals on the basis of
early test results. Given that our knowledge about the
exceptional performance of savants and prodigies and the
predictive validity of tests of basic abilities and talents
have increased considerably in the past decade, we briefly
review the evidence or rather the lack of evidence for
innate abilities and talent.
Performance of Prodigies and Savants
When the large collection of reports of amazing and in-
explicable performance is surveyed, one finds that most
of them cannot even be firmly substantiated and can only
rarely be replicated under controlled laboratory condi-
tions.
Probably the best established phenomenon linked
to talent in music is perfect pitch, or more accurately
absolute pitch (AP). Only approximately 0.01% of the
general population have AP and are able to correctly name
each of the 64 different tones, whereas average musicians
without AP can distinguish only approximately five or
six categories of pitches when the pitches are presented
in isolation (Takeuchi & Hulse, 1993). Many outstanding
musicians display AP, and they first reveal their ability
in early childhood. With a few exceptions, adults appear
to be unable to attain AP in spite of extended efforts.
Hence the characteristics of absolute pitch would seem
to meet all of the criteria of innate talent, although there
is some controversy about how useful this ability is to the
expert musicians. In a recent review of
AP,
Takeuchi and
Hulse (1993) concluded that the best account of the ex-
tensive and varied evidence points toward a theory that
"states AP can be acquired by anyone [italics added], but
only during a limited period of development" (p. 355).
They found that all individuals with AP had started with
music instruction early—nearly always before age five or
six—and that several studies had been successful in
teaching AP to three- to six-year-old children. At older
ages children perceive relations between pitches, which
leads to accurate relative pitch, something all skilled mu-
sicians have. "Young children prefer to process absolute
rather than the relative pitches of musical stimuli" (p.
356).
Similar developmental trends from individual fea-
tures to relational attributes are found in other forms of
perception during the same age period (Takeuchi & Hulse,
1993).
Rather than being a sign of innate talent, AP ap-
pears to be a natural consequence of appropriate instruc-
tion and of ample opportunities to interact with a musical
instrument, such as a piano, at very young ages.
Other proposed evidence for innate talent comes
from studies of prodigies in music and chess who are able
to attain high levels of performance even as young chil-
dren. In two influential books, Feldman (1980, 1986)
showed that acquisition of skills in prodigies follows the
same sequence of stages as in other individuals in the
same domain. The primary difference is that prodigies
attain higher levels faster and at younger ages. For ex-
ample, an analysis of Picasso's early drawings as a child
shows that he encountered and mastered problems in
drawing in ways similar to less gifted individuals (Pariser,
1987).
Feldman (1986) also refuted the myth that prod-
2 In his recent book Creating Minds, Gardner (1993a) examined the
lives of seven great innovators, such as Einstein, Picasso, Stravinsky, and
Gandhi. Each was selected to exemplify outstanding achievements in
one of seven different intelligences. Gardner's careful analysis reveals
that the achievements of each individual required a long period of intense
preparation and required the coincidence of many environmental factors.
Striking evidence for traditional talent, such as prodigious achievements
as a child, is notably absent, with the exception of Picasso. The best
evidence for talent, according to Gardner, is their rapid progress once
they made a commitment to a particular domain of expertise. These
findings are not inconsistent with Gardner's views on talent because
innovation and creation of new ideas are fundamentally different from
high achievements in a domain due to talent. Gardner wrote, "in the
case of
a
universally acclaimed prodigy, the prodigy's talents mesh per-
fectly with current structure of the domain and the current tastes of the
field. Creativity, however, does not result from such perfect meshes"
(pp.
40-41).
728August 1994 American Psychologist
igies acquire their skills irrespective of the environment.
In fact, he found evidence for the exact opposite, namely
that "the more powerful and specific the gift, the more
need for active, sustained and specialized intervention"
(p.
123) from skilled teachers and parents. He described
the classic view of gifts, in which parents are compelled
to support their development, when he wrote, "When
extreme talent shows itself it demands nothing less than
the willingness of one or both of the parents to give up
almost everything else to make sure that the talent is de-
veloped" (p. 122). A nice case in point is the child art
prodigy Yani (Ho, 1989), whose father gave up his own
painting career so as not to interfere with the novel style
that his daughter was developing. Feldman (1980, 1986)
argued that prodigious performance is rare because ex-
treme talent for a specific activity in a particular child
and the necessary environmental support and instruction
rarely coincide.
Contrary to common
belief,
most child prodigies
never attain exceptional levels of performance as adults
(Barlow, 1952; Feldman, 1986). When Scheinfeld (1939)
examined the reported basis of the initial talent assess-
ment by parents of famous musicians, he found signs of
interest in music rather than objective evidence of unusual
capacity. For example, Fritz Kreisler was "playing violin"
(p.
239) with two sticks at age four, and Yehudi Menuhin
had a "response to violins at concerts" (p. 239) at the
age of one and a half years. Very early start of music
instruction would then lead to the acquisition of absolute
pitch. Furthermore, the vast majority of exceptional adult
performers were never child prodigies, but instead they
started instruction early and increased their performance
due to a sustained high level of training (Bloom, 1985).
The role of early instruction and maximal parental sup-
port appears to be much more important than innate
talent, and there are many examples of parents of excep-
tional performers who successfully designed optimal en-
vironments for their children without any concern about
innate talent (see Ericsson, Krampe, & Tesch-Romer,
1993,
and Howe, 1990). For example, as part of an ed-
ucational experiment, Laslo and Klara Polgar (Forbes,
1992) raised one of their daughters to become the young-
est international chess grand master ever—she was even
younger than Bobby Fischer, who was the youngest male
achieving that exceptional level of chess-playing skill. In
1992 the three Polgar daughters were ranked first, second,
and sixth in the world among women chess players, re-
spectively.
Although scientists and the popular press have been
interested in the performance of prodigies, they have been
especially intrigued by so-called savants. Savants are in-
dividuals with a low level of general intellectual func-
tioning who are able to perform at high levels in some
special tasks. In a few cases the parents have reported
that these abilities made their appearances suddenly, and
they cited them as gifts from God (Ericsson & Faivre,
1988;
Feldman, 1986). More careful study of the emer-
gence of these and other cases shows that their detection
may in some cases have been sudden, but the opportu-
nities,
support, and encouragement for learning had pre-
ceded the original performance by years or even decades
(Ericsson & Faivre, 1988; Howe, 1990; Treffert, 1989).
Subsequent laboratory studies of the performance of sa-
vants have shown them to reflect acquired skills. For ex-
ample, savants who can name the day of the week of an
arbitrary date ( e.g., November 5, 1923) generate their
answers using instructable methods that allow their per-
formance to be reproduced by a college student after a
month of training (for a review see Ericsson & Faivre,
1988).
The only ability that cannot be reproduced after
brief training concerns some savants' reputed ability to
play a piece of music after a single hearing.
However, in a carefully controlled study of a music
savant (J.L.), Charness, Clifton, and MacDonald (1988)
showed that reproduction of short (2- to 12-note) tonal
sequences and recall of from two to four chords (4 notes
each) depended on whether the sequences or chords fol-
lowed Western scale structure. Unfamiliar sequences that
violated musical conventions were poorly recalled past 6
notes.
Short, familiar sequences of notes and chords were
accurately recalled, although recall dropped with length
of sequence so that only 3 (of 24) 12-note familiar se-
quences were completely correct. Attempts to train J.L.
to learn temporally static 16-note melodies were unsuc-
cessful. Even in the case of the musical savant studied by
Sloboda, Hermelin, and O'Connor (1985), who was able
to memorize a new piece of music, there was a marked
difference in success with a conventional versus a tonally
unconventional piece. Thus, music savants, like their
normally intelligent expert counterparts, need access to
stored patterns and retrieval structures to enable them
to retain long, unfamiliar musical patterns. Given that
savants cannot read music—most of them are blind
they have to acquire new music by listening, which would
provide motivation and opportunities for the development
of domain-specific memory skills.
In summary, the evidence from systematic labora-
tory research on prodigies and savants provides no evi-
dence for giftedness or innate talent but shows that ex-
ceptional abilities are acquired often under optimal en-
vironmental conditions.
Prediction of Future Success Based on Innate
Abilities and Talent
The importance of basic processes and capacities is central
to many theorists in the human information-processing
tradition. In conceptual analogies with computers, in-
vestigators often distinguish between hardware (the phys-
ical components of the computer) and software (computer
programs and stored data). In models of human perfor-
mance, "software" corresponds to knowledge and strat-
egies that can be readily changed as a function of training
and learning, and "hardware" refers to the basic elements
that cannot be changed through training. Even theorists
such as Chase and Simon (1973), who acknowledge that
"practice is the major independent variable in the ac-
quisition of skill" (p. 279), argue in favor of individual
differences in talent that predispose people to be successful
August 1994 American Psychologist729
in different domains: "Although there clearly must be a
set of specific aptitudes (e.g., aptitudes for handling spatial
relations) that together comprise a talent for chess, in-
dividual differences in such aptitudes are largely over-
shadowed by immense differences in chess experience"
(p.
297). Bloom (1985) went through many different do-
mains to point out some necessary qualities that are likely
to be mostly inborn, such as "motor coordination, speed
of reflexes and hand-eye coordination" (p. 546). These
views were consistent with the available information at
the time, such as high heritabilities for many of these
characteristics. In their review of sport psychology,
Browne and Mahoney (1984) argued for the importance
of fixed physiological traits for elite performance of ath-
letes and wrote that "there is good evidence that the limits
of physiological capacity to become more efficient with
training is determined by genetics" (p. 609). They cited
research reporting that percentage of muscle fibers and
aerobic capacity "are more than 90% determined by
heredity for both male and female" (p. 609). However,
more recent reviews have shown that heritabilities in ran-
dom samples of twins are much lower and range between
zero and 40% (Malina & Bouchard, 1991).
It is curious how little empirical evidence supports
the talent view of expert and exceptional performance.
Ever since Galton, investigators have tried to measure
individual differences in unmodifiable abilities and basic
cognitive and perceptual capacities. To minimize any in-
fluence from prior experience, they typically base their
tests on simple tasks. They measure simple reaction time
and detection of sensory stimuli and present meaningless
materials, such as nonsense syllables and lists of digits,
in tests of memory capacity. A recent review (Ericsson,
Krampe, & Tesch-Romer, 1993) showed that efforts to
measure talent with objective tests for basic cognitive and
perceptual motor abilities have been remarkably unsuc-
cessful in predicting final performance in specific do-
mains. For example, elite athletes are able to react much
faster and make better perceptual discriminations to rep-
resentative situations in their respective domains, but their
simple reaction times and perceptual acuity to simple
stimuli during laboratory tests do not differ systematically
from those of other athletes or control subjects (for reviews
see Regnier, Salmela, & Russell, 1993, and Starkes &
Deakin, 1985). Chess players' and other experts' superior
memory for brief presentation of representative stimuli
from their domains compared with that of novices is
eliminated when the elements of the same stimuli are
presented in a randomly arranged format (Chase & Si-
mon, 1973; see Ericsson & Smith, 1991a, for a review).
The performance of elite chess players on standard tests
of spatial ability is not reliably different from control sub-
jects (Doll & Mayr, 1987). The domain specificity of su-
perior performance is striking and is observed in many
different domains of expertise (Ericsson, Krampe, &
Tesch-Romer, 1993).
This conclusion can be generalized with some qual-
ifications to current tests of such general abilities as verbal
and quantitative intelligence. These tests typically mea-
sure acquired knowledge of mathematics, vocabulary, and
grammar by successful performance on items testing
problem solving and comprehension. Performance during
and immediately after training is correlated with IQ, but
the correlations between this type of ability test and per-
formance in the domain many months and years later is
reduced (even after corrections for restriction of range)
to such low values that Hulin, Henry, and Noon (1990)
questioned their usefulness and predictive validity. At the
same time, the average IQ of expert performers, especially
in domains of expertise requiring thinking, such as chess,
has been found to be higher than the average of the normal
population and corresponds roughly to that of college
students. However, IQ does not reliably discriminate the
best adult performers from less accomplished adult per-
formers in the same domain.
Even physiological and anatomical attributes can
change dramatically in response to physical training. Al-
most everyone recognizes that regular endurance and
strength training uniformly improves aerobic endurance
and strength, respectively. As the amount and intensity
or physical training is increased and maintained for long
periods, far-reaching adaptations of the body result (see
Ericsson, Krampe, & Tesch-Romer, 1993, for a review).
For example, the sizes of hearts and lungs, the flexibility
of
joints,
and the strength of bones increase as the result
of training, and the nature and extent of these changes
appear to be magnified when training overlaps with phys-
ical development during childhood and adolescence. Fur-
thermore, the number of capillaries supplying blood to
trained muscles increases, and muscle fibers can change
their metabolic properties from fast twitch to slow twitch.
With the clear exception of height, a surprisingly large
number of anatomical characteristics show specific
changes and adaptations to the specific nature of extended
intense training, which we describe in more detail later
in this article.
If one accepts the necessity of extended intense
training for attaining expert performance—a claim that
is empirically supported later in this article—then it fol-
lows that currently available estimates of heritability of
human characteristics do not generalize to expert per-
formance. An estimate of heritability is valid only for the
range of environmental effects for which the studied sub-
jects have been exposed. With a few exceptions, studies
of heritabilities have looked only at random samples of
subjects in the general population and have not restricted
their analyses to individuals exposed to extended training
in a domain. The remaining data on exceptional and ex-
pert performers have not been able to demonstrate sys-
tematic genetic influences. Explanations based on selec-
tive access to instruction and early training in a domain
provide as good or in some cases better accounts of fa-
milial relations of expert performers, such as the lineage
of musicians in the Bach family (see Ericsson, Krampe,
& Tesch-Romer, 1993, for a review).
In summary, we argue that the traditional assump-
tions of basic abilities and capacities (talent) that may
remain stable in studies of limited and short-term practice
730August 1994 American Psychologist
do not generalize to superior performance acquired over
years and decades in a specific domain. In addition, we
will later review evidence showing that acquired skill can
allow experts to circumvent basic capacity limits of short-
term memory and of the speed of basic reactions, making
potential basic limits irrelevant. Once the potential for
change through practice is recognized, we believe that a
search for individual differences that might be predictive
of exceptional and expert performance should refocus on
the factors advocated by Charles Darwin (quoted in Gal-
ton, 1908) in a letter to Galton after reading the first part
of Galton's (1869/1979) book: "You have made a convert
of an opponent in one sense, for I have always maintained
that excepting fools, men did not differ much in intellect,
only in zeal and hard work; I still think this is an eminently
important difference" (p. 290). In commenting on Dar-
win's remark, Galton (1908) agreed but argued that
"character, including the aptitude for work, is heritable"
(p.
291). On the basis of their review, Ericsson, Krampe,
and Tesch-Romer (1993) found that motivational factors
are more likely to be the locus of heritable influences
than is innate talent. We explicate the connection between
these "motivational" factors and the rate of improving
performance in a specific domain in the last section of
this article.
There are two parts to the remaining portion of this
article. First, we show that it is possible to study and
analyze the mechanisms that mediate expert perfor-
mance. We also show that the critical mechanisms reflect
complex, domain-specific cognitive structures and skills
that performers have acquired over extended periods of
time.
Hence, individuals do not achieve expert perfor-
mance by gradually refining and extrapolating the per-
formance they exhibited before starting to practice but
instead by restructuring the performance and acquiring
new methods and skills. In the final section, we show that
individuals improve their performance and attain an ex-
pert level, not as an automatic consequence of more ex-
perience with an activity but rather through structured
learning and effortful adaptation.
The Study of Expert Performance
The conceptions of expert performance as primarily an
acquired skill versus a reflection of innate talents influence
how expert performance and expert performers are stud-
ied. When the goal is to identify critical talents and ca-
pacities, investigators have located experts and then com-
pared measurements of their abilities with those of control
subjects on standard laboratory tests. Tests involve simple
stimuli and tasks in order to minimize any effects of pre-
viously acquired knowledge and skill. Given the lack of
success of this line of research, we advocate a different
approach that identifies the crucial aspects of experts'
performance that these experts exhibit regularly at a su-
perior level in their domain. If experts have acquired their
superior performance by extended adaptation to the spe-
cific constraints in their domains, we need to identify
representative tasks that incorporate these constraints to
be able to reproduce the natural performance of experts
under controlled conditions in the laboratory. We illus-
trate this method of designing representative test situa-
tions with several examples later in this section. Once the
superior performance of experts can be reliably repro-
duced in a test situation, this performance can then be
analyzed to assess its mediating acquired mechanisms.
Following Ericsson and Smith (1991a), we define expert
performance as consistently superior performance on a
specified set of representative tasks for the domain that
can be administered to any subject. The virtue of defining
expert performance in this restricted sense is that the def-
inition both meets all the criteria of laboratory studies of
performance and comes close to meeting those for eval-
uating performance in many domains of expertise.
Perceived Experts Versus Consistent Expert
Performance
In many domains, rules have evolved and standardized
conditions, and fair methods have been designed for mea-
suring performance. The conditions of testing in many
sports and other activities, such as typing competitions,
are the same for all participating individuals. In other
domains, the criteria for expert performance cannot be
easily translated into a set of standardized tasks that cap-
tures and measures that performance. In some domains,
expert performance is determined by judges or by the
results of competitive tournaments. Psychometric meth-
ods based on tournament results, most notably in chess
(Elo,
1986), have successfully derived latent measures of
performance on an interval scale. In the arts and sciences,
selected individuals are awarded prizes and honors by
their peers, typically on the basis of significant achieve-
ments such as published books and research articles and
specific artistic performances.
Some type of metric is of course required to identify
superior performance. The statistical term outlier may be
a useful heuristic for judging superior performance. Usu-
ally, if someone is performing at least two standard de-
viations above the mean level in the population, that in-
dividual can be said to be performing at an expert level.
In the domain of chess (Elo, 1986), the term expert is
defined as a range of chess ratings (2000-2199) approx-
imately two to three standard deviations (200 rating
points) above the mean (1600 rating points) and five to
six standard deviations above the mean of chess players
starting to play in chess tournaments.
In most domains it is easier to identify individuals
who are socially recognized as experts than it is to specify
observable performance at which these individuals excel.
The distinction between the perception of expertise and
actual expert performance becomes increasingly impor-
tant as research has shown that the performance of some
individuals who are nominated as experts is not measur-
ably superior. For example, studies have found that fi-
nancial experts' stock investments yield returns that are
not consistently better than the average of the stock mar-
ket, that
is,
financial experts' performance does not differ
from the result of essentially random selection of stocks.
When successful investors are identified and their sub-
August 1994 American Psychologist731
sequent investments are tracked, there is no evidence for
sustained superiority. A large body of evidence has been
accumulated showing that experts frequently do not out-
perform other people in many relevant tasks in their do-
mains of expertise (Camerer & Johnson, 1991). Experts
may have much more knowledge and experience than
others, yet their performance on critical tasks may not
be reliably better than that of nonexperts. In summary,
researchers cannot seek out experts and simply assume
that their performance on relevant tasks is superior; they
must instead demonstrate this superior performance.
Identifying and Capturing Expert Performance
For most domains of expertise, people have at least an
intuitive conception of the kind of activities at which an
expert should excel. In everyday life, however, these ac-
tivities rarely have clearly denned starting and end points,
nor do the exact external conditions of a specific activity
reoccur. The main challenge is thus to identify particular
well-defined tasks that frequently occur and that capture
the essence of expert performance in a specific domain.
It is then possible to determine the contexts in which
each task naturally occurs and to present these tasks in
a controlled context to a larger group of other experts.
De Groot's (1946/1978) research on expertise in
chess is generally considered the pioneering effort to cap-
ture expert performance. Ability in chess playing is de-
termined by the outcomes of chess games between op-
ponents competing in tournaments. Each game
is
different
and is rarely repeated exactly except for the case of moves
in the opening phase of the game. De Groot, who was
himself a chess master, determined that the ability to play
chess is best captured in the task of selecting the next
move for a given chess position taken from the middle of
the game between two chess masters. Consistently supe-
rior performance on this task for arbitrary chess positions
logically implies a very high level of skill. Researchers can
therefore elicit experts' superiority in performing a critical
task by presenting the same unfamiliar chess position to
any number of chess players and asking them to find the
best next move. De Groot demonstrated that performance
on this task discriminates well between chess players at
different levels of skill and thus captures the essential
phenomenon of ability to play this game.
In numerous subsequent studies, researchers have
used a similar approach to study the highest levels of
thinking in accepted experts in various domains of ex-
pertise (Chi et al., 1988; Ericsson & Smith, 1991b). If
expert performance reflects extended adaptation to the
demands of naturally occurring situations, it is important
that researchers capture the structure of these situations
in order to elicit maximal performance from the experts.
Furthermore, if the tasks designed for research are suf-
ficiently similar to normal situations, experts can rely on
their existing skills, and no experiment-specific changes
are necessary. How similar these situations have to be to
real-life situations is an empirical question. In general,
researchers should strive to define the simplest situation
in which experts' superior performance can still be reli-
ably reproduced.
Description and Analysis of Expert
Performance
The mere fact that it is possible to identify a set of rep-
resentative tasks that can elicit superior performance from
experts under standardized conditions is important. It
dramatically reduces the number of contextual factors
that can logically be essential for reproducing that superior
performance. More important, it allows researchers to
reproduce the phenomenon of expert performance under
controlled conditions and in a reliable fashion. Research-
ers can thus precisely describe the tasks and stimuli and
can theoretically determine which mechanisms are ca-
pable of reliably producing accurate performance across
the set of
tasks.
Part of the standard methodology in cog-
nitive psychology is to analyze the possible methods sub-
jects could use to generate the correct response to a spe-
cific task, given their knowledge about procedures and
facts in the domain. The same methodology can be ap-
plied to tasks that capture expert performance. Because,
however, the knowledge experts may apply to a specific
task is quite extensive and complex, it is virtually im-
possible for nonexperts to understand an analysis of such
a task. Instead of describing such a case, we illustrate the
methodology and related issues with a relatively simple
skill, mental multiplication.
Mental Multiplication: An Illustration of Text
Analysis
In a study of mental multiplication, the experimenter
typically reads a problem to a subject: What is the result
of multiplying 24 by 36? The subject then reports the
correct answer—864. It may be possible that highly ex-
perienced subjects recognize that particular problem and
retrieve the answer immediately from memory. That
possibility is remote for normal subjects, and one can
surmise that they must calculate the answer by relying
on their knowledge of the multiplication table and familiar
methods for complex multiplication. The most likely
method is the paper-and-pencil method taught in the
schools, where 24 X 36 is broken down into 24 X 6 and
24 X 30 and the products are added together (illustrated
as Case B in Table 1). Often students are told to put the
highest number first. By this rule, the first step in solving
24 X 36 is to rearrange it as 36 X 24 and then to break
it down as 36 X 4 and 36 X 20 (Case A). More sophis-
ticated subjects may recognize that 24 X 36 is equivalent
to (30 - 6) X (30 + 6) and use the formula (a - b) X (a
+ b) = a2 - b2, thus calculating 24 X 36 as 302 - 62 =
900
36 = 864 (Case C). Other subjects may recognize
other shortcuts, such as 24 X 36 = (2 X 12) X (3 X 12)
= 6 X 122 = 6 X 144 (Case D). Skilled mental calculators
often prefer to calculate the answer in the reverse order,
as is illustrated in Case E. Especially for more complex
problems this procedure allows them to report the first
digit of the final result long before they have completed
the calculation of the remaining digits. Because most
732August 1994 American Psychologist
Table 1
Five
Possible
Methods of Mentally Multiplying 24 by 36
and a Think-Aloud Protocol from a Subject Generating the
Correct Answer
Mental multiplication
Method A
24
X 36
144
72
864
Method B
36
X 24
144
72
864
Method C
24 X 36 =
= 130 - 6) X (30 + 6)
= 302 - 62 =
= 900 - 36 = 864
Method D
24 X 36 =2X12X3X12 =
= 6X 122 = 6X 144 = 864
Method
E
AB
X CD
100 X A X C
10 X A X D
10XCXB
B X D
24
X 36
600
120
120
24
864
Think-aloud protocol
36 times 24
4
carry the—no wait
4
carry the 2
14
144
0
36 times 2 is
12