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The Cambridge Handbook of Expertiseand Expert Performance

This is the first handbook where the worlds fore-most experts on expertise review our scientificknowledge on expertise and expert performanceand how experts may differ from non-expertsin terms of their development, training, reason-ing, knowledge, social support, and innate talent.Methods are described for the study of expertsknowledge and their performance of representa-tive tasks from their domain of expertise. Thedevelopment of expertise is also studied by retro-spective interviews and the daily lives of expertsare studied with diaries. In 15 major domainsof expertise, the leading researchers summarizeour knowledge of the structure and acquisi-tion of expert skill and knowledge and discussfuture prospects. General issues that cut acrossmost domains are reviewed in chapters on var-ious aspects of expertise, such as general andpractical intelligence, differences in brain activity,self-regulated learning, deliberate practice, aging,knowledge management, and creativity.

K. Anders Ericsson is Conradi Eminent Scholarand Professor of Psychology at Florida StateUniversity. In 1976 he received his Ph.D. inPsychology from University of Stockholm,Sweden, followed by a postdoctoral fellowship atCarnegie-Mellon University. His current researchconcerns the structure and acquisition of expertperformance and in particular how expert per-formers acquire and maintain their superiorperformance by extended deliberate practice. Hehas published many books, including Toward aGeneral Theory of Expertise: Prospects and Lim-its and The Road to Excellence: The Acquisition ofExpert Performance in the Arts and Sciences, Sports,and Games.

Neil Charness is Professor of Psychology atFlorida State University and Research Associateat the Pepper Institute on Aging and Public Policyat Florida State University. He received his Ph.D.

(1974) in Psychology from Carnegie-MellonUniversity. His research on expertise focuses onhow people develop and preserve high-level per-formance across the life span. He has publishedmore than 100 articles and chapters on the top-ics of expert performance, age, and human fac-tors. He is on the editorial boards of Psychologyand Aging, the Journal of Gerontology: Psychologi-cal Sciences, and Gerontechnology.

Paul J. Feltovich is a Research Scientist at theFlorida Institute for Human and Machine Cog-nition, Pensacola, Florida. He has conductedresearch and published on topics such as expert-novice differences in complex cognitive skills,conceptual understanding and misunderstandingfor complex knowledge, and novel means ofinstruction in complex and ill-structured know-ledge domains. Since joining FIHMC, he hasbeen investigating coordination, regulation, andteamwork in mixed groups of humans andintelligent software agents. He has authorednearly 100 professional articles and two priorbooks.

Robert R. Hoffman, Ph.D., is a Research Scien-tist at the Florida Institute for Human and Mach-ine Cognition, Pensacola, Florida. He is also anAdjunct Instructor at the Department of Psychol-ogy of the University of West Florida in Pensacola.His research has garnered him a designation asone of the pioneers of Expertise Studies. Hoffmanhas been recognized on an international level inat least five disciplines remote sensing, meteo-rology, experimental psychology, human factors,and artificial intelligence. Within psycholinguis-tics, he has made pioneering contributions, havingfounded the journal Metaphor & Symbol, and hav-ing written extensively on the theory of analogy.He is coeditor of the regular department HumanCentered Computing in the journal IEEE: Intel-ligent Systems.

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The Cambridge Handbookof Expertise and Expert Performance

Edited by

K. Anders EricssonFlorida State University

Neil CharnessFlorida State University

Paul J. FeltovichFlorida Institute for Human and Machine Cognition

Robert R. HoffmanFlorida Institute for Human and Machine Cognition

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Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, So Paulo

Cambridge University PressThe Edinburgh Building, Cambridge , UK

First published in print format

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Cambridge University Press 2006

2006

Information on this title: www.cambridg e.org /9780521840972

This publication is in copyright. Subject to statutory exception and to the provision ofrelevant collective licensing agreements, no reproduction of any part may take placewithout the written permission of Cambridge University Press.

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Cambridge University Press has no responsibility for the persistence or accuracy of sfor external or third-party internet websites referred to in this publication, and does notguarantee that any content on such websites is, or will remain, accurate or appropriate.

Published in the United States of America by Cambridge University Press, New York

www.cambridge.org

hardback

eBook (EBL)

eBook (EBL)

hardback


Anders Ericsson would like to dedicate this Handbook to hiswife, Natalie; to his two children Lina and Jens; and

to his grandson, Jakob.

Neil Charness would like to dedicate this Handbook to his wife,Beth; to his two children, Michelle and Alan; and to his two

grandchildren, Benjamin and Madeline.

Paul Feltovich would like to dedicate this Handbook to his wife,Joan, and to his three children, Ellen, Andrew, and Anne.

Robert Hoffman would like to dedicate this Handbook to his wife,Robin, and to his two children Rachel and Eric.

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Contents

Acknowledgements page xi

Contributors xiii

p a r t iINTRODUCTION AND PERSPECTIVE

1. An Introduction to The Cambridge Handbook of Expertise and Expert Performance:Its Development, Organization, and Content 3K. Anders Ericsson

2 . Two Approaches to the Study of Experts Characteristics 21Michelene T. H. Chi

3 . Expertise, Talent, and Social Encouragement 31Earl Hunt

p a r t iiOVERVIEW OF APPROACHES TO THE STUDY OF EXPERTISE BRIEFHISTORICAL ACCOUNTS OF THEORIES AND METHODS

4. Studies of Expertise from Psychological Perspectives 41Paul J. Feltovich, Michael J. Prietula, & K. Anders Ericsson

5 . Educators and Expertise: A Brief History of Theories and Models 69Ray J. Amirault & Robert K. Branson

6. Expert Systems: A Perspective from Computer Science 87Bruce G. Buchanan, Randall Davis, & Edward A. Feigenbaum

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viii contents

7. Professionalization, Scientific Expertise, and Elitism: A SociologicalPerspective 105Julia Evetts, Harald A. Mieg, & Ulrike Felt

p a r t iiiMETHODS FOR STUDYING THE STRUCTURE OF EXPERTISE

8. Observation of Work Practices in Natural Settings 127William J. Clancey

9. Methods for Studying the Structure of Expertise: PsychometricApproaches 147Phillip L. Ackerman & Margaret E. Beier

10. Laboratory Methods for Assessing Experts and Novices Knowledge 167Michelene T. H. Chi

11. Task Analysis 185Jan Maarten Schraagen

12 . Eliciting and Representing the Knowledge of Experts 203Robert R. Hoffman & Gavan Lintern

13 . Protocol Analysis and Expert Thought: Concurrent Verbalizations ofThinking during Experts Performance on Representative Tasks 223K. Anders Ericsson

14. Simulation for Performance and Training 243Paul Ward, A. Mark Williams, & Peter A. Hancock

p a r t ivMETHODS FOR STUDYING THE ACQUISITION AND MAINTENANCE OFEXPERTISE

15 . Laboratory Studies of Training, Skill Acquisition, and Retention ofPerformance 265Robert W. Proctor & Kim-Phuon L. Vu

16. Retrospective Interviews in the Study of Expertise and ExpertPerformance 287Lauren A. Sosniak

17. Time Budgets, Diaries, and Analyses of Concurrent Practice Activities 303Janice M. Deakin, Jean Cote, & Andrew S. Harvey

18. Historiometric Methods 319Dean Keith Simonton

p a r t vDOMAINS OF EXPERTISE

p a r t v.aPROFESSIONAL DOMAINS

19. Expertise in Medicine and Surgery 339Geoff Norman, Kevin Eva, Lee Brooks, & Stan Hamstra


Contents ix

2 0. Expertise and Transportation 355Francis T. Durso & Andrew R. Dattel

2 1. Expertise in Software Design 373Sabine Sonnentag, Cornelia Niessen, & Judith Volmer

2 2 . Professional Writing Expertise 389Ronald T. Kellogg

2 3 . Professional Judgments and Naturalistic Decision Making 403Karol G. Ross, Jennifer L. Shafer, & Gary Klein

2 4. Decision-Making Expertise 421J. Frank Yates & Michael D. Tschirhart

2 5 . The Making of a Dream Team: When Expert Teams Do Best 439Eduardo Salas, Michael A. Rosen, C. Shawn Burke, Gerald F. Goodwin,& Stephen M. Fiore

p a r t v.bARTS, SPORTS, & MOTOR SKILLS

2 6. Music 457Andreas C. Lehmann & Hans Gruber

2 7. Expert Performance in Sport: A Cognitive Perspective 471Nicola J. Hodges, Janet L. Starkes, & Clare MacMahon

2 8. Artistic Performance: Acting, Ballet, and Contemporary Dance 489Helga Noice & Tony Noice

2 9. Perceptual-Motor Expertise 505David A. Rosenbaum, Jason S. Augustyn, Rajal G. Cohen, & Steven A. Jax

p a r t v.cGAMES AND OTHER TYPES OF EXPERTISE

30. Expertise in Chess 523Fernand Gobet & Neil Charness

31. Exceptional Memory 539John M. Wilding & Elizabeth R. Valentine

32 . Mathematical Expertise 553Brian Butterworth

33 . Expertise in History 569James F. Voss & Jennifer Wiley

p a r t viGENERALIZABLE MECHANISMS MEDIATING EXPERTISE AND GENERALISSUES

34. A Merging Theory of Expertise and Intelligence 587John Horn & Hiromi Masunaga


x contents

35 . Tacit Knowledge, Practical Intelligence, and Expertise 613Anna T. Cianciolo, Cynthia Matthew, Robert J. Sternberg, & Richard K. Wagner

36. Expertise and Situation Awareness 633Mica R. Endsley

37. Brain Changes in the Development of Expertise: Neuroanatomical andNeurophysiological Evidence about Skill-Based Adaptations 653Nicole M. Hill & Walter Schneider

38. The Influence of Experience and Deliberate Practice on the Development ofSuperior Expert Performance 683K. Anders Ericsson

39. Development and Adaptation of Expertise: The Role of Self-RegulatoryProcesses and Beliefs 705Barry J. Zimmerman

40. Aging and Expertise 723Ralf Th. Krampe & Neil Charness

41. Social and Sociological Factors in the Development of Expertise 743Harald A. Mieg

42 . Modes of Expertise in Creative Thinking: Evidence from Case Studies 761Robert W. Weisberg

Author Index 789

Subject Index 819


Acknowledgments

Anders Ericsson wants to gratefully ack-nowledge the financial support provided bythe John D. and Catherine T. MacArthurFoundation, Grant #32005 -0, which sup-ported the planning and the invitation ofhandbook authors during his year as a Fel-low at the Center for Advanced Study in theBehavioral Sciences. He also would like tocredit the Conradi Eminent Scholar Endow-ment at the Florida State Foundation for itssupport during the editing phase of the workon the handbook.

Neil Charness gratefully acknowledgessupport from the National Institutes ofHealth / National Institute on Aging, GrantsR01 AG13969 and 1P01 AG 17211, that per-mitted him both to edit and contribute tochapters in this handbook.

Paul Feltovich and Robert Hoffmanwould like to acknowledge the Florida Insti-tute for Human and Machine Cognitionfor support during the preparation of thehandbook.

We also want to thank M. Anne Britt(Northern Illinois University), Jamie I. D.Campbell (University of Saskatchewan,Canada), Randall Davis (MIT), Leo Gugerty

(Clemson University), Alice F. Healy (Uni-versity of Colorado), Anastasia Kitsantas,(George Mason University), Reinhold Kliegl(University of Potsdam, Germany), Ralf Th.Krampe (University of Leuven, Belgium),Richard E. Mayer (University of Califor-nia, Santa Barbara), Daniel Morrow (Uni-versity of Illinois at Urbana-Champaign),Kathleen Mosier (San Francisco State Uni-versity), Gary D. Phye (Iowa State Univer-sity), Mauro Pesenti (Universite Catholiquede Louvain, Belgium), Pertti Saariluoma(University of Jyvaskyla, Finland), MikeSaks (University of Lincoln, UK), JohnB. Shea (Indiana University), Dean KeithSimonton (University of California, Davis),J. Michael Spector (Florida State Univer-sity), Janet L. Starkes (McMaster Univer-sity, Canada), Gershon Tenenbaum (FloridaState University), Oliver Vitouch (Univer-sity of Klagenfurt, Austria), and Richard K.Wagner (Florida State University) for theirfull-length reviews of particular chapters,along with the numerous authors of chap-ters within the handbook itself, who pro-vided insightful comments and suggestionsfor other chapters in this volume.

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Contributors

Phillip L. AckermanSchool of PsychologyGeorgia Institute of Technology

Ray J. AmiraultInstructional TechnologyWayne State University

Jason S. AugustynDepartment of PsychologyUniversity of Virginia

Margaret E. BeierDepartment of PsychologyRice University

Robert K. BransonInstructional SystemsCollege of EducationFlorida State University

Lee R. BrooksDepartment of PsychologyMcMaster University

Bruce BuchananComputer Science DepartmentUniversity of Pittsburgh

C. Shawn BurkeDepartment of PsychologyInstitute for Simulation & TrainingUniversity of Central Florida

Brian ButterworthInstitute of Cognitive NeuroscienceUniversity College London

Neil CharnessPsychology DepartmentFlorida State University

Michelene T. H. ChiLearning Research and Development CenterUniversity of Pittsburgh

Anna T. CiancioloCommand Performance Research, Inc.

William J. ClanceyNASA/Ames Research Center

Rajal G. CohenDepartment of PsychologyPennsylvania State University

Jean CoteSchool of Physical and Health Education,Queens University

Andrew DattelDepartment of PsychologyTexas Tech University

Randall DavisComputer Science and Artificial Intelligence

LaboratoryMassachusetts Institute of Technology

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xiv contributors

Janice DeakinSchool of Physical and Health Education,Queens University

Frank T. DursoDepartment of PsychologyTexas Tech University

Mica EndsleySA Technologies

K. Anders EricssonDepartment of PsychologyFlorida State University

Kevin EvaClinical Epidemiology and BiostatisticsFaculty of Health SciencesMcMaster University

Julia EventsSchool of Sociology & Social PolicyUniversity of Nottingham

Edward A. FeigenbaumDepartment of Computer ScienceStanford University

Ulrike FeltInstitut fur WissenschaftsforschungUniversitat Wien

Paul J. FeltovichFlorida Institute for Human and Machine

Cognition (FIHMC)

Stephen M. FioreInstitute for Simulation & TrainingUniversity of Central Florida

Fernand GobetDepartment of Human SciencesBrunel University

Gerald F. GoodwinU.S. Army Research Institute

Hans GruberInstitute for EducationUniversity of Regensburg

Stanley J. HamstraDepartment of SurgeryUniversity of Toronto

Peter Hancock.Department of Psychology and

Institute for Simulation and TrainingUniversity of Central Florida

Andrew HarveyDepartment of EconomicsSt. Marys University

Nicole HillLearning Research and Development

CenterUniversity of Pittsburgh

Nicola J. HodgesSchool of Human KineticsUniversity of British Columbia

Robert R. HoffmanFlorida Institute for Human and Machine

Cognition (FIHMC)

John L. HornDepartment of PsychologyUniversity of Southern California

Earl HuntDepartment of PsychologyUniversity of Washington

Steven A. JaxMoss Rehabilitation Research Institute

Ronald T. KelloggDepartment of PsychologySaint Louis University

Gary KleinKlein Associates Inc

Ralf Th. KrampeDepartment of PsychologyUniversity of Leuven

Andreas C. LehmannHochschule fuer Musik Wuerzburg

Gavan LinternAdvanced Information Engineering Services, IncA General Dynamics Company

Clare MacmahonDepartment of PsychologyFlorida State University

Hiromi MasunagaDepartment of Educational Psychology,

Administration, and CounselingCalifornia State University, Long Beach

Cynthia T. MatthewPACE CenterYale University

Harald A. MiegGeographisches InstitutHumboldt-Universitat zu Berlin

Cornelia NiessenDepartment of PsychologyUniversity of Konstanz

Helga NoiceDepartment of PsychologyElmhurst College


contributors xv

Tony NoiceDepartment of TheatreElmhurst College

Geoff NormanClinical Epidemiology and BiostatisticsFaculty of Health SciencesMcMaster University

Michael J. PrietulaGoizueta Business SchoolEmory University

Robert W. ProctorDepartment of Psychological SciencesPurdue University

Michael RosenDepartment of Psychology andInstitute for Simulation and TrainingUniversity of Central Florida

David A. RosenbaumDepartment of PsychologyPennsylvania State University

Karol G. RossKlein Associates Inc

Eduardo SalasDepartment of Psychology andInstitute for Simulation and TrainingUniversity of Central Florida

Walter SchneiderLearning Research and Development


Jan Maarten SchraagenTNO Defence, Security and Safety

Jennifer L. ShaferKlein Associates Inc

Dean Keith SimontonDepartment of PsychologyUniversity of California, Davis

Sabine SonnentagDepartment of PsychologyUniversity of Konstanz

Janet L. StarkesDepartment of KinesiologyMcMaster University

Robert J. SternbergSchool of Arts and SciencesTufts University

Michael TschirhartDepartment of PsychologyUniversity of Michigan

Elizabeth R. ValentineDepartment of PsychologyRoyal HollowayUniversity of London

Judith VolmerDepartment of PsychologyUniversity of Konstanz

James F. VossLearning Research and Development


Kim-Phuong L. VuDepartment of PsychologyCalifornia State University Long Beach

Richard K. WagnerFlorida Center for Reading ResearchDepartment of PsychologyFlorida State University

Paul WardHuman Performance LaboratoryLearning Systems InstituteFlorida State University

Robert W. WeisbergDepartment of PsychologyTemple University

John. M. Wilding,Department of PsychologyRoyal HollowayUniversity of London

Jennifer WileyDepartment of PsychologyUniversity of Illinois

A. Mark WilliamsResearch Institute for Sport and Exercise

SciencesLiverpool John Moores University

J. Frank YatesDepartment of Psychology & Ross School

of BusinessUniversity of Michigan

Barry J. ZimmermanDoctoral Program in Educational

PsychologyCity University of New York


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Par t I

INTRODUCTION ANDPERSPECTIVE

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C H A P T E R 1

An Introduction to Cambridge Handbookof Expertise and Expert Performance:

Its Development, Organization,and Content

K. Anders Ericsson

A significant milestone is reached when afield of scientific research matures to a pointwarranting publication of its first handbook.A substantial body of empirical findings,distinctive theoretical concepts and frame-works, and a set of new or adapted meth-ods justify a unifying volume. The growth ofthis field is evident from the publication of aseries of edited books on diverse sets of skillsand expertise from many domains during thelast several decades (Anderson, 1981; Bloom,1985a; Chase, 1973 ; Chi, Glaser, & Farr, 1988;Ericsson, 1996a; Ericsson & Smith, 1991a;Feltovich, Ford, & Hoffman, 1997; Hoffman,1992 ; Starkes & Allard, 1993 ; Starkes &Ericsson, 2003). And as in many other fields,the name of a branch of scientific study, inour case expertise and expert performance,often communicates the domain of studiedphenomena.

Expert, Expertise, and ExpertPerformance: Dictionary Definitions

Encyclopedias describe an Expert as onewho is very skillful and well-informed in

some special field (Websters New WorldDictionary, 1968, p. 168), or someone widelyrecognized as a reliable source of knowl-edge, technique, or skill whose judgment isaccorded authority and status by the pub-lic or his or her peers. Experts have pro-longed or intense experience through prac-tice and education in a particular field(Wikipedia, 2005). Expertise then refers tothe characteristics, skills, and knowledge thatdistinguish experts from novices and lessexperienced people. In some domains thereare objective criteria for finding experts,who are consistently able to exhibit supe-rior performance for representative tasksin a domain. For example, chess masterswill almost always win chess games againstrecreational chess players in chess tour-naments, medical specialists are far morelikely to diagnose a disease correctly thanadvanced medical students, and professionalmusicians can perform pieces of musicin a manner that is unattainable for lessskilled musicians. These types of superiorreproducible performances of representativetasks capture the essence of the respectivedomains, and authors have been encouraged

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4 the cambridge handbook of expertise and expert performance

to refer to them as Expert Performance inthis handbook.

In some domains it is difficult for non-experts to identify experts, and consequentlyresearchers rely on peer-nominations byprofessionals in the same domain. How-ever, people recognized by their peers asexperts do not always display superior per-formance on domain-related tasks. Some-times they are no better than novices evenon tasks that are central to the expertise,such as selecting stocks with superior futurevalue, treatment of psychotherapy patients,and forecasts (Ericsson & Lehmann, 1996).There are several domains where expertsdisagree and make inconsistent recommen-dations for action, such as recommend-ing selling versus buying the same stock.For example, expert auditors assessmentshave been found to differ more from eachother than the assessments of less experi-enced auditors (Bedard, 1991). Furthermore,experts will sometimes acquire differencesfrom novices and other people as a func-tion of their repetitive routines, which is aconsequence of their extended experiencerather than a cause for their superior perfor-mance. For example, medical doctors hand-writing is less legible than that of otherhealth professionals (Lyons, Payne, McCabe,& Fielder, 1998). Finally, Shanteau (1988)has suggested that experts may not need aproven record of performance and can adopta particular image and project outwardsigns of extreme self-confidence (p. 211) toget clients to listen to them and continueto offer advice after negative outcomes.After all, the experts are nearly always thebest qualified to evaluate their own per-formance and explain the reasons for anydeviant outcomes.

When the proposal for this Handbookwas originally prepared, the outline focusedmore narrowly on the structure and acqui-sition of highly superior (expert) perfor-mance in many different domains (Ericsson,1996b, 2004). In response to the requestsof the reviewers of that proposal, the finaloutline of the handbook covered a broaderfield that included research on the devel-opment of expertise and how highly expe-

rienced individuals accumulate knowledgein their respective domains and eventuallybecome socially recognized experts and mas-ters. Consequently, to reflect the scope ofthe Handbook it was entitled the CambridgeHandbook of Expertise and Expert Perfor-mance. The current handbook thus includesa multitude of conceptions of expertise,including perspectives from education, soci-ology, and computer science, along withthe more numerous perspectives from psy-chology emphasizing basic abilities, knowl-edge, and acquired skills. In this introductorychapter, I will briefly introduce some generalissues and describe the structure and con-tent of the Handbook as it was approved byCambridge University Press.

Tracing the Development of OurKnowledge of Expertiseand Expert Performance

Since the beginning of Western civiliza-tion there has been a particular interest inthe superior knowledge that experts havein their domain of expertise. The body ofknowledge associated with the domain ofexpertise in which a person is expert is aparticularly important difference betweenexperts and other individuals. Much of thisknowledge can be verbally described andshared with others to benefit decision mak-ing in the domain and can help educate stu-dents and facilitate their progress towardexpertise. The special status of the knowl-edge of experts in their domain of exper-tise is acknowledged even as far back as theGreek civilization. Socrates said that

I observe that when a decision has tobe taken at the state assembly aboutsome matter of building, they send for thebuilders to give their advice about the build-ings, and when it concerns shipbuildingthey send for the shipwrights, and simi-larly in every case where they are deal-ing with a subject which they think canbe learned and taught. But if anyone elsetries to give advice, whom they dont regardas an expert, no matter how handsome or


introduction 5

wealthy or well-born he is, they still willhave none of him, but jeer at him and createan uproar, until either the would-be speakeris shouted down and gives up of his ownaccord, or else the police drag him away orput him out on the order of the presidents.(Plato, 1991, pp. 1112 )

Aristotle relied on his own senses as theprimary source of scientific knowledge andsought out beekeepers, fishermen, hunters,and herdsmen to get the best and most reli-able information for his books on science(Barnes, 2000). He even tried to explainoccasional incorrect reports from some of hisinformants about how offspring of animalswere generated. For example, some of themsuggested that the ravens and the ibisesunite at the mouth (Aristotle, 2000, p. 315).But Aristotle notes: It is odd, however, thatour friends do not reason out how the semenmanages to pass through the stomach andarrive in the uterus, in view of the fact thatthe stomach concocts everything that getsinto it, as it does the nourishment (pp. 315& 317). Similarly, those who assert that thefemale fishes conceive as a result of swallow-ing the males semen have failed to noticecertain points (p. 311). Aristotle explainsthat Another point which helps to deceivethese people is this. Fish of this sort take onlya very short time over their copulation, withthe result that many fishermen even neversee it happening, for of course no fishermenever watches this sort of thing for the sake ofpure knowledge (p. 313). Much of Aristo-tles knowledge comes, at least partly, fromconsensus reports of professionals.

Much later during the Middle Ages,craftsmen formed guilds to protect them-selves from competition. Through arrange-ments with the mayor and/or monarch theyobtained a monopoly on providing partic-ular types of handcraft and services withset quality standards (Epstein, 1991). Theypassed on their special knowledge of howto produce products, such as lace, barrels,and shoes, to their students (apprentices).Apprentices would typically start at aroundage 14 and commit to serve and study withtheir master for around 7 years the lengthof time varied depending on the complex-

ity of the craft and the age and prior experi-ence of the apprentice (Epstein, 1991). Oncean apprentice had served out their contractthey were given a letter of recommendationand were free to work with other mastersfor pay, which often involved traveling toother cities and towns they were there-fore referred to as journeymen. When a jour-neyman had accumulated enough additionalskill and saved enough money, he, or occa-sionally she, would often return to his hometown to inherit or purchase a shop with toolsand apply to become a master of the guild.In most guilds they required inspection ofthe journeymans best work, that is, masterpieces, and in some guilds they administeredspecial tests to assess the level of perfor-mance (Epstein, 1991). When people wereaccepted as masters they were held responsi-ble for the quality of the products from theirshop and were thereby allowed to take onthe training of apprentices (See Amirault &Branson, Chapter 5 , and Chi, Chapter 2 , onthe progression toward expertise and mas-tery of a domain).

In a similar manner, the scholars guildwas established in the 12th and 13 th cen-tury as a universitas magistribus et pupil-lorum, or guild of masters and students(Krause, 1996, p. 9). Influenced by theUniversity of Paris, most universities con-ducted all instruction in Latin, where thestudents were initially apprenticed as artsstudents until they successfully completedthe preparatory (undergraduate) programand were admitted to the more advancedprograms in medicine, law, or theology. Tobecome a master, the advanced studentsneeded to satisfy a committee of examin-ers, then publicly defending a thesis, oftenin the town square and with local grocersand shoemakers asking questions (Krause,1996, p. 10). The goal of the universities wasto accumulate and explain knowledge, andin the process masters organized the exist-ing knowledge (See Amirault & Branson,Chapter 5). With the new organization ofthe existing knowledge of a domain, it wasno longer necessary for individuals to dis-cover the relevant knowledge and methodsby themselves.



Todays experts can rapidly acquire theknowledge originally discovered and accu-mulated by preceding expert practitionersby enrolling in courses taught by skilledand knowledgeable teachers using speciallyprepared textbooks. For example, in the13 th century Roger Bacon argued that itwould be impossible to master mathematicsby the then-known methods of learning(self-study) in less than 30 to 40 years(Singer, 1958). Today the roughly equiva-lent material (calculus) is taught in highlyorganized and accessible form in every highschool.

Sir Francis Bacon is generally viewed asone of the architects of the Enlightenmentperiod of Western Civilization and one ofthe main proponents of the benefits of gen-erating new scientific knowledge. In 1620he described in his book Novum Organumhis proposal for collecting and organizingall existing knowledge to help our civiliza-tion engage in learning to develop a bet-ter world. In it, he appended a listing ofall topics of knowledge to be included inCatalogus Historarium Particularium. Itincluded a long list of skilled crafts, suchas History of weaving, and of ancillaryskills associated with it, History of dyeing,History of leather-working, tanning, and ofassociated ancillary skills (Rees & Wakely,2004 , p. 483).

The guilds guarded their knowledge andtheir monopoly of production. It is there-fore not surprising that the same forces thateventually resulted in the French revolu-tion were directed not only at the oppres-sion by the king and the nobility, but alsoagainst the monopoly of services providedby the members of the guilds. Influenced bySir Francis Bacons call for an encyclopediccompilation of human knowledge, Diderotand DAlembert worked on assembling allavailable knowledge in the first Encyclopedie(Diderot & DAlembert, 196667), whichwas originally published in 175180.

Diderot was committed to the creation ofcomprehensive descriptions of the mechan-ical arts to make their knowledge availableto the public and to encourage research anddevelopment in all stages of production and

all types of skills, such as tannery, carpentry,glassmaking, and ironworking (Pannabecker,1994), along with descriptions of how tosharpen a feather for writing with ink, asshown in Figure 1.1. His goal was to describeall the raw materials and tools that were nec-essary along with the methods of produc-tion. Diderot and his associate contributorshad considerable difficulties gaining accessto all the information because of the unwill-ingness of the guild members to answer theirquestions. Diderot even considered sendingsome of his assistants to become apprenticesin the respective skills to gain access to all therelevant information (Pannabecker, 1994). Inspite of all the information and pictures (dia-grams of tools, workspaces, procedures, etc.,as is illustrated in Figure 1.2 showing oneof several plates of the process of printing)provided in the Encyclopedie, Diderot wasunder no illusion that the provided informa-tion would by itself allow anyone to becomea craftsman in any of the described arts andwrote: It is handicraft that makes the artist,and it is not in Books that one can learnto manipulate (Pannabecker, 1994 , p. 52).In fact, Diderot did not even address thehigher levels of cognitive activity, such asintuitive knowledge, experimentation, per-ceptual skills, problem-solving, or the anal-ysis of conflicting or alternative technicalapproaches (Pannabecker, 1994 , p. 52).

A couple of years after the French revo-lution the monopoly of the guilds as elim-inated (Fitzsimmons, 2003), including therestrictions on the practice of medicine andlaw. After the American Revolution and thecreation of the United States of Americalaws were initially created to require thatdoctors and lawyers be highly trained basedon the apprenticeship model, but pressure toeliminate elitist tendencies led to the repealof those laws. From 1840 to the end of the19th century there was no requirement forcertification to practice medicine and lawin the United States (Krause, 1996). How-ever, with time both France and Americarealized the need to restrict vital medicaland legal services to qualified profession-als and developed procedures for trainingand certification.


Figure 1.1. An illustration for how to sharpen a goose feather for writing with ink from Plate IVin the entry on Ecriture in the 23 rd volume of Encyclopedie ou dictionnare de raisonne dessciences, des artes et des metier (Diderot & DAlembert, 196667).

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Figure 1.2 . An illustration of the workspace of a printer with some of his type elements fromPlate I in the entry on Imprimerie in the 28th volume of Encyclopedie ou dictionnare deraisonne des sciences, des artes et des metier (Diderot & DAlembert, 196667).

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introduction 9

Over the last couple of centuries therehave been several major changes in the rela-tion between master and apprentice. Forexample, before the middle of the 19th cen-tury children of poor families would oftenbe taken on by teachers in exchange fora contractual claim for part of the futuredancers, singers, or musicians earnings asan adult (Rosselli, 1991). Since then thestate has gotten more involved in the train-ing of their expert performers, even out-side the traditional areas of academia andprofessional training in medicine, law, busi-ness, and engineering. In the late 19th cen-tury, public institutions such as the RoyalAcademy of Music were established to pro-mote the development of very high levels ofskill in music to allow native students com-pete with better trained immigrants (Rohr,2001). In a similar manner during the lat-ter part of the 20th century, many countriesinvested in schools and academies for thedevelopment of highly skilled athletes forimproved success in competitions during theOlympic Games and World Championships(Bloomfield, 2004).

More generally, over the last century therehave been economic developments withpublic broadcasts of competitions and per-formances that generate sufficient revenuefor a number of domains of expertise, such assports and chess, to support professional full-time performers as well as coaches, train-ers, and teachers. In these new domains,along with the traditional professions, cur-rent and past expert performers continueto be the primary teachers at the advancedlevel (masters), and their professional asso-ciations have the responsibility of certifyingacceptable performance and the permissionto practice. Accordingly, they hold the cloutin thus influencing training in professionalschools, such as law, medical, nursing, andbusiness schools testing is the tail thatwags the dog (Feltovich, personal commu-nication) as well as continuing educationtraining (see Evetts, Meig, & Felt, Chapter 7on sociological perspectives on expertise).The accumulation of knowledge about thestructure and acquisition of expertise in agiven domain, as well as knowledge about

the instruction and training of future pro-fessionals, has occurred, until quite recently,almost exclusively within each domain withlittle cross-fertilization of domains in termsof teaching, learning methods, and skill-training techniques.

It is not immediately apparent what isgeneralizable across such diverse domains ofexpertise, such as music, sport, medicine,and chess. What could possibly be sharedby the skills of playing difficult piecesby Chopin, running a mile in less thanfour minutes, and playing chess at a highlevel? The premise for a field studyingexpertise and expert performance is thatthere are sufficient similarities in the the-oretical principles mediating the phenom-ena and the methods for studying them indifferent domains that it would be possi-ble to propose a general theory of exper-tise and expert performance. All of thesedomains of expertise have been created byhumans. Thus the accumulated knowledgeand skills are likely to reflect similaritiesin structure that reflect both human bio-logical and psychological factors, as wellas cultural factors. This raises many chal-lenging problems for methodologies usedto describe the organization of knowledgeand mechanisms and reveals the medi-ating expert performance that generalizesacross domains.

Once we know how experts organizetheir knowledge and their performance, is itpossible to improve the efficiency of learn-ing to reach higher levels of expert perfor-mance in these domains? It should also bepossible to answer why different individ-uals improve their performance at differ-ent rates and why different people reachvery different levels of final achievement.Would a deeper understanding of the devel-opment and its mediating mechanisms makeit possible to select individuals with unusualpotential and to design better developmen-tal environments to increase the proportionof performers who reach the highest levels?Would it be possible even to facilitate thedevelopment of those rare individuals whomake major creative contributions to theirrespective domains?



Conceptions of Generalizable Aspectsof Expertise

Several different theoretical frameworkshave focused on broad issues on attainingexpert performance that generalize acrossdifferent domains of expertise.

Individual Differences in MentalCapacities

A widely accepted theoretical conceptargues that general innate mental capaci-ties mediate the attainment of exceptionalperformance in most domains of expertise.In his famous book, Heriditary Genius,Galton (1869/1979) proposed that across awide range of domains of intellectual activ-ity the same innate factors were required toattain outstanding achievement and the des-ignation of being a genius. He analyzed emi-nent individuals in many domains in GreatBritain and found that these eminent indi-viduals were very often the offspring ofa small number of families with muchhigher frequency than could be expected bychance. The descendents from these fami-lies were much more likely to make emi-nent contributions in very diverse domainsof activity, such as becoming famous politi-cians, scientists, judges, musicians, painters,and authors. This observation led Galton tosuggest that there must be a heritable poten-tial that allows some people to reach anexceptional level in any one of many differ-ent domains. After reviewing the evidencethat height and body size were heritableGalton (1869/1979) argued: Now, if this bethe case with stature, then it will be true asregards every other physical feature as cir-cumference of head, size of brain, weight ofgrey matter, number of brain fibres, &c.; andthence, a step on which no physiologist willhesitate, as regards mental capacity (pp. 3132 , emphasis added).

Galton clearly acknowledged the needfor training to reach high levels of perfor-mance in any domain. However, he arguedthat improvements are rapid only in thebeginning of training and that subsequentincreases become increasingly smaller, until

maximal performance becomes a rigidlydeterminate quantity (p. 15). Galton devel-oped a number of different mental testsof individual differences in mental capacity.Although he never related these measuresto the objective performance of experts onparticular real-world tasks, his views led tothe common practice of using psychome-tric tests for admitting students into pro-fessional schools and academies for artsand sports with severely limited availabil-ity of slots. These tests of basic ability andtalent were believed to identify the stu-dents with the capacity for reaching thehighest levels.

In the 20th century scientists began thepsychometric testing of large groups ofexperts to measure their powers of mentalspeed, memory, and intelligence. When theexperts performance was compared to con-trol groups of comparable education, therewas no evidence for Galtons hypothesis ofa general superiority for experts becausethe demonstrated superiority of experts wasfound to be limited to specific aspectsrelated to the particular domain of exper-tise. For example, the superiority of thechess experts memory was constrained toregular chess positions and did not gener-alize to other types of materials (Djakow,Petrowski, & Rudik, 1927). Not even IQcould distinguish the best among chess play-ers (Doll & Mayr, 1987) or the most success-ful and creative among artists and scientists(Taylor, 1975).

In a recent review, Ericsson and Lehmann(1996) found that (1) measures of basicmental capacities are not valid predictorsof attainment of expert performance in adomain, (2) the superior performance ofexperts is often very domain specific, andtransfer outside their narrow area of exper-tise is surprisingly limited, and (3) system-atic differences between experts and lessproficient individuals nearly always reflectattributes acquired by the experts duringtheir lengthy training. The reader is directedto the chapter by Horn and Masunaga (chap-ter 34) and to comprehensive reviews inSternberg and Grigorenko, 2003 , and Howe,Davidson, and Sloboda. 1998.


introduction 11

Expertise as the Extrapolation ofEveryday Skill to Extended Experience

A second general type of theoretical frame-works is based on the assumption that thesame learning mechanisms that account forthe acquisition of everyday skills can beextended to the acquisition of higher lev-els of skills and expertise. Studies in the19th century proposed that the acquisitionof high levels of skills was a natural con-sequence of extended experience in thedomains of expertise. For example, Bryanand Harter (1899) argued that ten years ofexperience were required to become a pro-fessional telegrapher. The most influentialand pioneering work on expertise was con-ducted in the 1940s by Adrian de Groot(1978), who invited international chess mas-ters and skilled club players to think aloudwhile they selected the best move for chesspositions. His analyses of the protocolsshowed that the elite players were able torecognize and generate chess moves thatwere superior to skilled club players by rely-ing on acquired patterns and planning (seeGobet & Charness, chapter 30, and Erics-son, chapter 13 , for a more detailed account).DeGroots dissertation was later translatedinto English in the late 1960s and early 1970s(deGroot, 1978) and had substantial impacton the seminal theory of expertise proposedby Herb Simon and Bill Chase (Simon &Chase, 1973).

In the 1950s and 1960s Newell and Simonproposed how information-processing mod-els of human problem solving could be im-plemented as computer programs, such asthe General Problem Solver (Ernst &Newell, 1969). In their seminal book, Hu-man Problem Solving, Newell and Simon(1972) argued that domain-general problemsolving was limited and that the thinkinginvolved in solving most tasks could be rep-resented as the execution of a sequence ofproduction rules such as IF ,THEN that incorporated specificknowledge about the task environment. Intheir theory of expertise, Simon and Chase(1973) made the fundamental assumptionthat the same patterns (chunks) that allo-

wed the experts to retrieve suitable actionsfrom memory were the same patterns thatmediated experts superior memory for thecurrent situation in a game. Instead of study-ing the representative task of playing chess,namely, selecting the best moves for chesspositions (Ericsson & Smith, 1991b; Vicente& Wang, 1998), Chase and Simon (1973)redirected the focus of research towardstudying performance of memory tasks as amore direct method of studying the charac-teristics of patterns that mediate improve-ment in skill. They found that there was aclear relation between the number of chesspieces recalled from briefly presented chesspositions and the players level of chessexpertise. Grand masters were able to repro-duce almost the entire chessboards (24 to 26pieces) by recalling a small number of com-plex chunks, whereas novices could recallonly around 4 pieces, where each piece wasa chunk. The masters superior memory wasassumed to depend on an acquired body ofmany different patterns in memory becausetheir memory for randomly rearranged chessconfigurations was markedly reduced. In factin such configurations they could recall onlyaround 5 to 7 pieces, which was only slightlybetter than the recall of novices.

Experts superiority for representativebut not randomly rearranged stimuli hassince been demonstrated in a large numberof domains. The relation between the mech-anisms mediating memory performance andthe mechanisms mediating representativeperformance in the same domains have beenfound to be much more complex than orig-inally proposed by Simon and Chase (1973)(see Gobet & Charness, Chapter 30, andWilding & Valentine, Chapter 31. See alsoEricsson & Kintsch, 1995 ; Ericsson, Patel, &Kintsch, 2000; Gobet & Simon, 1996; Simon& Gobet, 2000; Vicente & Wang, 1998).

Expertise as Qualitatively DifferentRepresentation and Organizationof Knowledge

A different family of approaches drawingon the Simon-Chase theory of expertise hasfocused on the content and organization of



the experts knowledge (Chi, Feltovich, &Glaser, 1981; Chi, Glaser, & Rees, 1982) andon methods to extract the experts knowl-edge to build computer-based models emu-lating the experts performance (Hoffman,1992). These approaches have studiedexperts, namely, individuals who are sociallyrecognized as experts and/or distinguishedby their extensive experience (typically over10 years) and by knowledge of a particularsubject attained through instruction, study,or practical experience. The work of RobertGlaser, Micheline Chi, and Paul Feltovichexamined the representations of knowledgeand problem solutions in academic domains,such as physics (See Chi, Chapters 3 and 10).Of particular importance, Chi studied chil-dren with extensive knowledge of chess anddinosaurs (See Chi, Chapter 10), and foundthese children displayed many of the samecharacteristics of the knowledge representa-tion of adult experts. This work on exper-tise is summarized in Feltovich, Prietula, andEricsson, Chapter 4 , Chi, Chapter 10, andHoffman and Lintern, Chapter 12 , and ina couple of edited volumes (Chi, Glaser, &Farr, 1988; Starkes & Allard, 1993).

In a parallel development in the com-puter science of the late 1970s and early1980s, Ed Feigenbaum and other researchersin the area of artificial intelligence and cog-nitive science have attempted to elicit theknowledge of experts (Hoffman, 1992) andto incorporate their knowledge in computermodels (c.f. expert systems) that seek toreplicate some of the decision making andbehavior of experts (see Buchanan, Davis, &Feigenbaum, Chapter 6, and Hoffman &Lintern, Chapter 12). There has been a long-standing controversy over whether highlyexperienced experts are capable of articu-lating the knowledge and methods that con-trol their generation of appropriate actions incomplex situations.

The tradition of skill acquisition of Bryanand Harter (1899), Fitts and Posner (1967),and Simon and Chase (1973) assumed thatexpert performance was associated withautomation and was virtually effortless per-formance based on pattern recognition anddirect access of actions. However, Polanyi

(1962 , 1966) is generally recognized as thefirst critic who saw that nonconscious andintuitive mediation limits the possibility ofeliciting and mapping the knowledge andrules that mediates experts intuitive actions.Subsequent discussion of the developmentof expertise by Dreyfus and Dreyfus (1986)and Benner (1984) has argued that the high-est levels of expertise are characterized bycontextually based intuitive actions that aredifficult or impossible to report verbally.Several chapters in this handbook proposemethods for uncovering tacit knowledgeabout the successful development of exper-tise (Cianciolo, Matthew, Wagner, & Stern-berg, Chapter 35), about methods of workthrough observation (Clancey, Chapter 8),Concept Mapping (Hoffman & Lintern,Chapter 12), similarity judgment (Chi,Chapter 10), and traditional psychometricanalyses of individual differences in perfor-mance (Ackerman & Beier, Chapter 9) orsimulated environments (Ward, Williams, &Hancock, Chapter 14). Other investigatorsargue that expert performers often continueto engage in deliberate practice in order toimprove and that these performers haveto actively retain and refine their mentalrepresentations for monitoring and control-ling their performance. This retained abil-ity to monitor performance allows them togive informative concurrent and retrospec-tive reports about the mediating sequencesof thoughts (see Ericsson, Chapter 13).

Expertise as Elite Achievement Resultingfrom Superior Learning Environments

There are other approaches to the studyof expertise that have focused on objec-tive achievement. There is a long tradi-tion of influential studies with interviewsof peer-nominated eminent scientists (Roe,1952) and analyses of biographical data onNobel Prize winners (Zuckerman, 1977)(see Simonton, Chapter 18, 1994 , for amore extensive account). In a seminal study,Benjamin Bloom and his colleagues (Bloom,1985a) interviewed international-level per-formers from six different domains of exper-tise ranging from swimming to molecular


introduction 13

genetics. All of the 120 participants had wonprizes at international competitions in theirrespective domains. They were all inter-viewed about their development, as weretheir parents, teachers, and coaches. Forexample, Bloom and his colleagues collectedinformation on the development of athleteswho had won international competitions inswimming and tennis. They also interviewedartists who have won international competi-tions in sculpting and piano playing and sci-entists who had won international awards inmathematics and molecular biology. In eachof these six domains Bloom (1985b) foundevidence for uniformly favorable learningenvironments for the participants. Bloom(1985b) concluded that the availability ofearly instruction and support by their fam-ily appeared to be necessary for attainingan international level of performance as anadult. He found that the elite performerstypically started early to engage in rele-vant training activities in the domain andwere supported both by exceptional teach-ers and committed parents. One of the con-tributors to the Handbook, Lauren Sosniak(1985a, 1985b, 1985c, 1985d), describes inChapter 16 the main findings from the orig-inal study (Bloom, 1985a), along with morerecent interview studies aimed to uncoverthe development of elite performers.

Expertise as Reliably Superior (Expert)Performance on Representative Tasks

It is difficult to identify the many mediat-ing factors that might have been responsi-ble for the elite performer to win an awardand to write a groundbreaking book. Wheneminence and expertise is based on a sin-gular or small number of unique creativeproducts, such as books, paintings, or musi-cal as compositions, it is rarely possible toidentify and study scientifically the key fac-tors that allowed these people to producethese achievements. Consequently, Ericssonand Smith (1991b) proposed that the studyof expertise with laboratory rigor requiresrepresentative tasks that capture the essenceof expert performance in a specific domainof expertise. For example, a world-class

sprinter will be able to reproduce superiorrunning performance on many tracks andeven indoors in a large laboratory. Similarly,de Groot (1978) found that the ability toselect the best move for presented chesspositions is the best correlate of chess rat-ings and performance at chess tournaments a finding that has been frequently replicated(Ericsson & Lehmann, 1996; van der Maas& Wagenmakers, 2005). Once it is possi-ble to reproduce the reliably superior perfor-mance of experts in a controlled setting, suchas a laboratory, it then becomes feasible toexamine the specific mediating mechanismswith experiments and process-tracing tech-niques, such as think aloud verbal reports(see Ericsson, Chapter 13 , and Ericsson &Smith, 1991b). The discovery of represen-tative tasks that measure adult expert per-formance under standardized conditions ina controlled setting, such as a laboratory,makes it possible to measure and comparethe performance of less-skilled individualson the same tasks. Even more important,it allows scientists to test aspiring perform-ers many times during their developmentof expertise, allowing the measurement ofgradual increases in performance.

The new focus on the measurementof expert performance with standardizedtasks revealed that experts, that is, indi-viduals identified by their reputation ortheir extensive experience, are not alwaysable to exhibit reliably superior perfor-mance. There are at least some domainswhere experts perform no better thanless-trained individuals and that sometimesexperts decisions are no more accuratethan beginners decisions and simple deci-sion aids (Camerer & Johnson, 1991; Bolger& Wright, 1992). Most individuals whostart as active professionals or as begin-ners in a domain change their behavior andincrease their performance for a limited timeuntil they reach an acceptable level. Beyondthis point, however, further improvementsappear to be unpredictable and the num-ber of years of work and leisure experiencein a domain is a poor predictor of attainedperformance (Ericsson & Lehmann, 1996).Hence, continued improvements (changes)



in achievement are not automatic conse-quences of more experience, and in thosedomains where performance consistentlyincreases, aspiring experts seek out partic-ular kinds of experience, that is, deliber-ate practice (Ericsson, Krampe, & Tesch-Romer, 1993). Such activities are designed,typically by a teacher, for the sole purposeof effectively improving specific aspects ofan individuals performance. A large bodyof research shows how deliberate prac-tice can change mediating mechanisms andthat the accumulated amounts of deliber-ate practice are related to the attained levelof performance (see Ericsson, Chapter 38,and Deakin, Cote, & Harvey, Chapter 17,Zimmerman, Chapter 38, as well as theedited books by Ericsson [1996a] and Starkes& Ericsson [2003]).

General Comments

In summary, there are a broad range ofapproaches to the study of the structure andacquisition of expertise as well as expert per-formance. Although individual researchersand editors may be committed to oneapproach over the others, this Handbookhas been designed to fairly cover a widerange of approaches and research topics inorder to allow authors to express their dif-ferent views. However, the authors havebeen encouraged to describe explicitly theirempirical criteria for their key terms, suchas experts and expert performance. Forexample, the authors have been asked toreport if the cited research findings involveexperts identified by social criteria, criteriaof lengthy domain-related experience, or cri-teria based on reproducibly superior perfor-mance on a particular set of tasks representa-tive of the individuals domain of expertise.

General Outline of the Handbook

The handbook is organized into six gen-eral sections. First, Section 1 introduces theHandbook with brief accounts of general per-spectives on expertise. In addition to thisintroductory chapter that outlines the orga-nization of the handbook, there are chap-

ters by two of the pioneers of the study ofcognitive skill and expertise. Michelene Chi(Chapter 2) describes two approaches to thestudy of expertise and Earl Hunt (Chapter 3)gives his general perspective on the princi-pal factors related to expertise. In a recentbook Hunt (1995) has made a convincingcase for the increasing importance of highlevels of skill in occupations of the future. Heargues that with the development of tech-nology to automate less complex jobs themost important occupations of the futurewill require creative design and planning thatcannot be easily automated. He foresees arapidly increasing need to train students toeven higher levels of expertise to continuethe development of our modern society. Thekey competitive differences between com-panies of the future may not have to dowith raw materials and monetary resourcesbut with human capital, namely, the abili-ties of the employees. The Nobel Prize win-ner Gary Becker has for a long time madethe case for the critical role of educationand human capital in our current industri-alized world, and especially the crucial roleof highly accomplished people. He (Becker,2002) illustrated this claim by a quotefrom Microsoft founder Bill Gates: Take our20 best people away and . . . Microsoft wouldbecome an unimportant company (Becker,2002 , p. 8).

The second section of the Handbookcontains reviews of the historical devel-opment of the study of expertise in fourmajor disciplines, namely, psychology, edu-cation, computer science, and sociology.Three pioneers in the psychological study ofexpertise, Paul Feltovich, Michael Prietula,and Anders Ericsson, describe the develop-ment of the study of expertise in psychol-ogy (Chapter 4). One of the pioneers in thedevelopment of instructional design, RobertBranson, has together with Ray Amirault(Chapter 5) described the role of exper-tise in the historical development of educa-tional methods and theories. Three of thepioneers in the development of expert sys-tems, Bruce Buchanan, Randall Davis, andEdward Feigenbaum (Chapter 6), describethe role of expertise in shaping contempo-rary approaches in computer science and


introduction 15

artificial intelligence. Finally, Julia Evetts,Harald Mieg, and Ulrike Felt (Chap-ter 7) provide a description of the relevantapproaches to the study of expertise fromthe point of view of sociology.

The next two sections of the Handbookreview the core methods for studying thestructure (Section 3) and acquisition (Sec-tion 4) of expertise and expert performance.Each of the chapters in Sections 3 and 4has been written by one of the pioneer-ing researchers who have developed thesemethods and approaches for use in researchon expertise and expert performance. Thechapters consist of a historical background,a detailed description of the recommendedmethodology with a couple of examples,and a general review of the type of empir-ical evidence that has been collected. In thefirst chapter of Section 3 William Clancey(Chapter 8) gives an overview of the ethno-graphic observational methods for study-ing the behavior of experts. Philip Ack-erman and Margaret Beier (Chapter 9)review the use of psychometric methods forstudying expertise. Michelene Chi (Chap-ter 10) describes how laboratory meth-ods have been used to assess the struc-ture of knowledge. Jan Maarten Schraagen(Chapter 11) describes how tasks presentedto skilled and less-skilled individuals canbe analyzed and how a task analysis canguide data analysis and theory construction.Robert Hoffman and Gavin Lintern (Chap-ter 12) review methods for how knowledgeof experts can be elicited and represented byinterviews, Concept Maps, and abstraction-decomposition diagrams. Anders Ericsson(Chapter 13) describes how the elicitationof think-aloud protocols can allow inves-tigators to trace the thought processes ofexperts while they perform representativetasks from their domain. Finally, Paul Ward,Mark Williams, and Peter Hancock (Chap-ter 14) review how simulated environmentscan both be used to measure experts rep-resentative performance as well as be usedfor training.

Section 4 contains chapters examiningmethods for studying how skill, exper-tise, and expert performance develop andare acquired through practice. In the first

chapter, Robert Proctor and Kim-PhuonVu (Chapter 15) describe how laboratorymethods for the study of skilled perfor-mance can inform research on expertise andexpert performance. Lauren Sosniak (Chap-ter 16) discusses how she and her colleaguesused retrospective interviews to describethe development of expertise in the clas-sic studies led by Benjamin Bloom (1985a),along with some recent extensions of thatwork. Janice Deakin, Jean Cote, and AndrewHarvey (Chapter 17) use diaries and describedifferent methods to study how expert per-formers spend their time and how expertsallocate their practice time. In the finalchapter of this section, Dean Simonton(Chapter 18) reviews the methods of histo-riometrics and how data about the develop-ment of eminent performers can be collectedand analyzed.

Section 5 consists of fifteen chapters thatreview our current knowledge about exper-tise and expert performance in particulardomains and represents the core of thisHandbook. Each chapter has been writtenby internationally respected experts on theassociated areas of expertise and containsa brief historic background followed by areview and future directions. The chap-ters in Section 5 have been broken downinto three subsections. The first subsec-tion is focused on different types of profes-sional expertise, namely, medicine (Chap-ter 19 by Geoff Norman, Kevin Eva, LeeBrooks, and Stan Hamstra), transportation,such as driving, flying, and airplane control(Chapter 20 by Francis Durso and AndrewDattel), software design (Chapter 21 bySabine Sonnentag, Cornelia Niessen, andJudith Volmer), and writing (Chapter 22 byRonald Kellogg). There are two chapters onvarious aspects of decision making, namely,judgments in dynamic situations (natu-ral decision making, Chapter 23 by KarolRoss, Jennifer Shafer, and Gary Klein) anddecision-making expertise (Chapter 24 byFrank Yates & Michael Tschirhart), followedby Chapter 25 by Eduardo Salas, MichaelRosen, Shawn Burke, Gerald Goodwin, andStephen Fiore on research on expert teams.The second subsection contains chaptersthat review expert performance in music



(Chapter 26 by Andreas Lehmann andHans Gruber) and in sports (Chapter 27by Nicola Hodges, Janet Starkes, and ClareMacMahon), and expertise in other typesof arts, such as acting, ballet, and dance(Chapter 28 by Helga Noice and TonyNoice). The final chapter in this subsec-tion reviews research on perceptual-motorskills (Chapter 29 by David Rosenbaum,Jason Augustyn, Rajal Cohen, and StevenJax). The third and final subsection coversthe findings in a diverse set of domains ofexpertise, including games. The first chap-ter (Chapter 30 by Fernand Gobet andNeil Charness) describes the pioneering andinfluential work on expertise in the game ofchess. The next chapter (Chapter 31 by JohnWilding and Elizabeth Valentine) reviewsresearch on exceptional memory, in particu-lar for information that most people havedifficulty remembering, such as numbers,names, and faces. The last two chaptersreview research on mathematical ability andexpertise (Chapter 32 by Brian Butterworth)and expertise in history (Chapter 33 by JimVoss and Jennifer Wiley) an example of aknowledge-based domain.

In the last section of the Handbook wehave invited some of the worlds lead-ing researchers on general theoretical issuesthat are cutting across different domainsof expertise to review the current state ofknowledge. In the first chapter John Hornand Hiromi Masunaga (Chapter 34) dis-cuss the relation between general intelli-gence and expertise. In the following chapterAnna Cianciolo, Cynthia Mattew, RichardWagner, and Robert Sternberg (Chapter 35)review the relation between expertise andcentral concepts, such as practical intelli-gence and tacit knowledge. Mica Endsley(Chapter 36) reviews evidence for situa-tional awareness, namely, experts superiorability to perceive and monitor criticalaspects of situations during performance.The next three chapters focus on aspects oflearning. Nicole Hill and Walter Schneider(Chapter 37) review the neurological evi-dence on physiological adaptations result-ing from the acquisition of expertise. AndersEricsson (Chapter 38) reviews the evidence

for the key role of deliberate practice in caus-ing physiological adaptations and the acqui-sition of mechanisms that mediate expertperformance. Finally, Barry Zimmerman(Chapter 39) describes the importance ofself-regulated learning in the developmentof expertise. The last three chapters reviewgeneral issues in expertise. Ralf Krampeand Neil Charness (Chapter 40) reviewthe effects of aging on expert performanceand how it might be counteracted. HaraldMieg (Chapter 41) reviews the importanceof social factors in the development ofexpertise. Finally, Robert Weisberg (Chapter42) discusses the relation between expertiseand creativity.

Conclusion

This Handbook has been designed to provideresearchers, students, teachers, coaches, andanyone interested in attaining expertise witha comprehensive reference to methods, find-ings, and theories related to expertise andexpert performance. It can be an essentialtool for researchers, professionals, and stu-dents involved in the study or the training ofexpert performance and a necessary sourcefor college and university libraries, as wellas public libraries. In addition, the Hand-book is designed to provide a suitable textfor graduate courses on expertise and expertperformance. More generally, it is likely thatprofessionals, graduate students, and evenundergraduates who aspire to higher levelsof performance in a given domain can learnfrom experts pathways to superior perfor-mance in similar domains.

Many researchers studying expertise andexpert performance are excited and person-ally curious about the established researchfindings that most types of expertise requireat least a decade of extended efforts to attainthe mechanisms mediating superior perfor-mance. There is considerable knowledgethat is accumulating about generalizationsacross many domains about the acquisitionand refinement of these mechanisms duringan extended period of deliberate practice.The generalizable insights range from the


introduction 17

characteristics of ideal training environ-ments, to the methods for fostering moti-vation by providing both emotional supportand attainable training tasks of a suitable dif-ficulty level. This theoretical framework hasseveral implications.

It implies that if someone is interestedin the upper limits of human performanceand the most effective training to achievethe highest attainable levels, they shouldstudy the training techniques and perfor-mance limits of experts who have spenttheir entire life maximizing their perfor-mance. This assumption also implies that thestudy of expert performance will provideus with the best current evidence on whatis humanly possible to achieve with todaysmethods of training and how these elite per-formers are able to achieve their highest lev-els of performance. Given that performancelevels are increasing every decade in mostdomains of expertise, scientists will need towork with elite performers and their coachesto discover jointly the ever-increasing levelsof improved performance.

The framework has implications for edu-cation and professional training of perfor-mance for all the preliminary levels thatlead up to the expert levels in professionaldomains of expertise. By examining howthe prospective expert performers attainedlower levels of achievement, we shouldbe able to develop practice environmentsand foster learning methods that help peo-ple to attain the fundamental representa-tions of the tasks and the self-regulatoryskills that were necessary for the prospec-tive experts to advance their learning tohigher levels.

With the rapid changes in the relevantknowledge and techniques required for mostjobs, nearly everyone will have to con-tinue their learning and even intermittentlyrelearn aspects of their professional skills.The life-long quest for improved adapta-tion to task demands will not be limited toexperts anymore. We will all need to adoptthe characteristics and the methods of theexpert performers who continuously striveto attain and maintain their best level ofachievement.

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Author Notes

This article was prepared in part with supportfrom the FSCW/Conradi Endowment Fund ofFlorida State University Foundation. The authorwants to thank Neil Charness, Paul Feltovich,Len Hill, Robert Hoffman, and Roy Roring fortheir valuable comments on earlier drafts of thischapter.


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C H A P T E R 2

Two Approaches to the Studyof Experts Characteristics

Michelene T. H. Chi

This chapter differentiates two approachesto the study of expertise, which I callthe absolute approach and the relativeapproach, and what each approach impliesfor how expertise is assessed. It then summa-rizes the characteristic ways in which expertsexcel and the ways that they sometimesseem to fall short of common expectations.

Two Approaches to the Studyof Expertise

The nature of expertise has been studied intwo general ways. One way is to study trulyexceptional people with the goal of under-standing how they perform in their domainof expertise. I use the term domain looselyto refer to both informal domains, such assewing and cooking, and formal domains,such as biology and chess. One could chooseexceptional people on the basis of theirwell-established discoveries. For example,one could study how Maxwell constructeda quantitative field concept (Nersessian,1992). Or one could choose contemporaryscientists whose breakthroughs may still be

debated, such as pathologist Warren and gas-troenterologist Marshalls proposal that bac-teria cause peptic ulcers (Chi & Hausmann,2003 ; Thagard, 1998; also see the chaptersby Wilding & Valentine, Chapter 31, Simon-ton, Chapter 18, and Weisberg, Chapter 42).

Several methods can be used to identifysomeone who is truly an exceptional expert.One method is retrospective. That is, bylooking at how well an outcome or prod-uct is received, one can determine who is oris not an expert. For example, to identify agreat composer, one can examine a quanti-tative index, such as how often his or hermusic was broadcast (Kozbelt, 2004). A sec-ond method may be some kind of concur-rent measure, such as a rating system as aresult of tournaments, as in chess (Elo, 1965),or as a result of examinations (Masunaga &Horn, 2000), or just measures of how wellthe exceptional expert performs his task. Athird method might be the use of some inde-pendent index, if it is available. In chess,for example, there exists a task called theKnights Tour that requires a player to movea Knight Piece across the rows of a chessboard, using legal Knight Moves. The time it

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2 2 the cambridge handbook of expertise and expert performance

Table 2 .1. A proficiency scale (adapted from Hoffman, 1998).

Naive One who is totally ignorant of a domain

Novice Literally, someone who is new a probationary member. There has been someminimal exposure to the domain.

Initiate Literally, a novice who has been through an initiation ceremony and has begunintroductory instruction.

Apprentice Literally, one who is learning a student undergoing a program of instructionbeyond the introductory level. Traditionally, the apprentice is immersed in thedomain by living with and assisting someone at a higher level. The length of anapprenticeship depends on the domain, ranging from about one to 12 years inthe Craft Guilds.

Journeyman Literally, a person who can perform a days labor unsupervised, although workingunder orders. An experienced and reliable worker, or one who has achieved alevel of competence. Despite high levels of motivation, it is possible to remainat this proficiency level for life.

Expert The distinguished or brilliant journeyman, highly regarded by peers, whosejudgments are uncommonly accurate and reliable, whose performance showsconsummate skill and economy of effort, and who can deal effectively withcertain types of rare or tough cases. Also, an expert is one who has specialskills or knowledge derived from extensive experience with subdomains.

Master Traditionally, a master is any journeyman or expert who is also qualified to teachthose at a lower level. Traditionally, a master is one of an elite group of expertswhose judgments set the regulations, standards, or ideals. Also, a master can bethat expert who is regarded by the other experts as being the expert, or thereal expert, especially with regard to sub-domain knowledge.

takes to complete the moves is an indicationof ones chess skill (Chi, 1978). Although thistask is probably not sensitive enough to dis-criminate among the exceptional experts, atask such as this can be adapted as an index ofexpertise. In short, to identify a truly excep-tional expert, one often resorts to some kindof measure of performance. The assessmentof exceptional experts needs to be accuratesince the goal is to understand their supe-rior performance. Thus, this approach stud-ies the remarkable few to understand howthey are distinguished from the masses.

Though expertise can be studied in thecontext of exceptional individuals, thereis a tacit assumption in the literature thatperhaps these individuals somehow havegreater minds in the sense that the globalqualities of their thinking might be dif-ferent (Minsky & Papert, 1974 , p. 59). Forexample, they might utilize more power-ful domain-general heuristics that novicesare not aware of, or they may be natu-rally endowed with greater memory capacity(Pascual-Leone, 1970; Simonton, 1977). Thisline of reasoning is extended to cognitive

functioning probably because genetic inheri-tance does seem to be a relevant componentfor expertise in music and sports. In short,the tacit assumption is that greatness or cre-ativity arises from chance and unique innatetalent (Simonton, 1977). Lets call this typeof work in psychology the study of excep-tional or absolute expertise.

A second research approach to expertiseis to study experts in comparison to novices.This relative approach assumes that exper-tise is a level of proficiency that novices canachieve. Because of this assumption, thedefinition of expertise for this contras-tive approach can be more relative, in thesense that the more knowledgeable groupcan be considered the experts and the lessknowledgeable group t

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