Handbook of Behavior Genetics Yong-Kyu Kim Editor

Handbook of Behavior Genetics

123 Editor Yong-Kyu Kim University of Georgia Athens, GA USA [email protected]

ISBN 978-0-387-76726-0 e-ISBN 978-0-387-76727-7 DOI 10.1007/978-0-387-76727-7

Library of Congress Control Number: 2008941695

c Springer Science+Business Media, LLC 2009 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.

Printed on acid-free paper springer.com Dedicated to my teachers Preface

Behavior genetics is an interdisciplinary area combining the behavioral sciences and genetics. The study of behavior genetics has become increasingly important as we see growth spurts in finding genes involved in complex behaviors following on advances in molecular genetic techniques. This domain has been growing rapidly since the 1970s and increasingly receives attention from many different disciplines. It has now become a vast common ground for sci- entists from very diverse fields including psychology, psychiatry, neurology, endocrinology, biochemistry, neuroimaging, and genetics. When I was invited to organize this book by Springer, I was preparing for a new course, Behavior Genetics, at the University of Georgia in fall, 2005. Only a few textbooks were available at that time, but I could not find good references for graduate students and scien- tists. I thought that we needed to offer research guides to the studies of genetic and environ- mental influences on a variety of complex behaviors in humans and animals. I had little idea about the proper scope for such a book. I contacted senior colleagues of the Behavior Genet- ics Association and they gave me excellent advice. I initially invited contributors who were largely members of the Behavior Genetics Association and the handbook was outlined with 14 chapters. As the Handbook developed, it became clear that the first draft was not sufficient to cover all important domains in behavior genetics. In the second meeting with contributors during the BGA meeting in Hollywood, CA, we discussed expanding the handbook to other related domains, such as evolutionary psychology, health behavior, and neurosciences. I invited additional contributors from other disciplines, and added chapters on the history of behavior genetics, quantitative methods and models, as well as more studies of animal models. Now the handbook stands with 34 chapters and integrates many of the basic issues in behavior genetics. In each chapter, current research and issues on the selected topics are intensively reviewed and directions for future research on these topics are highlighted: new research designs, ana- lytic methods, and their implications are addressed. It is anticipated that the handbook will contribute to our understanding of behavior genetics and future research endeavors in the 21st century. Chapter 1 addresses a history of behavior genetics going back to some of Plato’s ideas and discusses the natureÐnurture controversies on behavior in the modern era which sometimes brought about uproar in our community. In Part I, we address designs and methods in behavior genetic research. Chapters 2 and 4 introduce statistical models and analyses, i.e., biometrical models and multivariate genetic analyses, which explain genetic and environmental causes of covariation between quantitative traits and comorbidity between disorders. In Chapter 3, quantitative trait locus (QTL) analysis is introduced and methods of linkage and association mapping of continuous traits are discussed. Results of the QTL analyses in several quantitative traits are presented throughout this volume. Chapter 5 addresses the importance of animals as models of human behaviors Ð cognition, personality, and pathology are presented in this volume. Part II addresses the genetics of cognition in humans and animals with nine selected top- ics. Chapter 6 discusses genetic and environmental influences on general intelligence using

vii viii Preface twin studies, followed by new twin research designs, analytic methods, findings, and their implications. In Chapter 7, behavioral genetic research on cognitive aging is reviewed: genetic and environmental contributions to age-related changes in cognitive abilities; contributions of genes and lifestyle variables to dementia, and to the terminal decline in cognitive functioning; and quantitative methods for investigating cognitive aging are presented. Chapter 8 addresses behavioral genetic research on reading, and the genetic and environmental etiologies of read- ing ability and disability are discussed. Chapter 9 explores behavioral and molecular genetic studies elucidating the role of the genome in the development and manifestation of disorders of speech and language. The human brain continues to show dynamic changes from child- hood into adulthood. Genetic and environmental influences in brain volumes are addressed in Chapter 10. Using quantitative magnetic resonance imaging (MRI), brain structures in patients with a clear genetic etiology are reviewed. Genetic approaches to the search for genes asso- ciated with brain volume are discussed. Cognitive abilities in animals as models of human behavior are presented in Chapters 11, 12, 13, and 14. Quantitative and molecular genetic approaches to cognition research in rodents are presented in Chapter 11. Cognitive deficits affected by genetic manipulations and mouse models for human cognitive disabilities are dis- cussed. Specifically, Chapter 12 reviews human cognitive impairment associated with chromo- somal abnormalities, and mouse models of trisomy 21 are discussed addressing the relation- ships among genes, brain, and cognitive function. Drosophila (fruit fly) models of Alzheimer’s disease are introduced in Chapter 13. Pathological roles of Aβ peptides in fly brains, memory defects, and locomotor dysfunctions are discussed. Chapter 14 addresses Drosophila courtship songs which are utilized for intersexual selection and species recognition in nature. Quantita- tive and molecular genetic studies on the phylogenetic patterns of song evolution in different species groups are reviewed. In Part III, the genetics of personality in humans and animals is addressed with 10 selected topics. Personality is influenced by both genes and environment during development. Chapter 15 explores genotypeÐenvironment correlation through a review of the behavioral genetic literature on genetic and environmental influences on family relationships. It is very important that behavioral genetic models that measure behaviors of interest reflect the content of the domains. Chapter 16 reviews behavioral genetic methods and models for personality research and theory, and addresses some methodological issues. Chapter 17 addresses the roles of specific genes, i.e., DRD4 and 5-HTTLPR genes, contributing to the multifaceted dimen- sions of human personality, including altruism. Temperament, developing early in life and possibly forming the basis for later personality and psychopathology, is explored in Chapter 18 in which quantitative and molecular genetic findings, as well as endophenotypic approaches, are discussed. Sexual orientation is a controversial issue in our communities. A growing body of evidence suggests that familial and genetic factors affect human sexual orientation. Quan- titative and molecular genetic studies on sexual orientation are reviewed in Chapter 19. Three chapters introduce animal models of personality and aggression. Chapter 20 explores personal- ity differences in rats widely used in laboratories and discusses anatomical and neurochemical analyses in this endeavor. Behavioral and genetic research on offensive aggression in mice is reviewed and comparative genetic studies of aggression across species are addressed in Chap- ter 21. Chapter 22 discusses aggressive behavior in fruit flies from the ecological, genetic, neurological, and evolutionary perspectives. Approximately 10% of the population are left- handers. The history, determination, and etiology of handedness are addressed in Chapter 23. Chapter 24 introduces exercise behavior as a new discipline in behavior genetics. A large pro- portion of adults in the world do not regularly engage in exercise, although benefits of exercise are well documented. Genetic determinants of variability in exercise behavior are discussed. In Part IV the genetics of psychopathology is represented with nine selected topics. Some psychiatric disorders like ADHD are only diagnosed by questionnaires or psychiatric inter- views, rather than by clinical tests, and consequently the genetic studies of the disorders can vary as a function of applied assessment methods and informants. Chapter 25 addresses such behavioral measure issues concerning ADHD. Depression and anxiety have their origins Preface ix

in childhood and arise from genetic and shared environmental effects. Epidemiological and behavior genetic research on childhood depression and anxiety are discussed in Chapter 26. Autism is familial and, thus, relatives of probands with autism are at high risk for depres- sion, anxiety, and personality attributes. Chapter 27 reviews current findings in the genetic epidemiology of autism and its etiological issues concerning the definition of autism pheno- types are discussed. Two chapters address substance abuse behaviors, that is, smoking, drugs, and drinking. Smoking behaviors aggregate in families and in peer networks due to genetic dispositions and common environmental influences. Chapter 28 reviews behavioral genetic research on smoking behavior and nicotine dependence, using Finnish sample studies, and its comorbidities with other substance use, depression, and schizophrenia are discussed. Behav- ioral and molecular genetic research on the use and abuse of both alcohol and drugs is reviewed in Chapter 29. Substance abuse and substance use disorder co-occur with conduct disorder and antisocial behavior. Chapter 30 gives results of a meta-analysis of twin and adoption studies examining genetic and environmental influences on conduct disorder and antisocial behavior. Association and linkage studies for genes influencing antisocial behavior are discussed. Chap- ter 31 explores the behavioral and molecular genetic approaches to the origins of two major psychoses: schizophrenia and bipolar mood disorder. The concept of endophenotypes, which are measured intermediate traits or states between genotypes (genetic liability) and pheno- types (disorders), is discussed. Chapter 32 discusses indepth longitudinal ”high-risk” studies that intend to identify endophenotypes in the first-degree relatives of schizophrenic probands and to offer putative behavioral predictors of future schizophrenia spectrum disorders. Mouse models of cognitive dysfunctions in schizophrenia are explored in Chapter 33 where the role of dopamine in attention and working memory is discussed. Finally, in Chapter 34, future directions for behavior genetics are addressed. It is not surprising that, at the final publication date of a book like the Handbook of Behavior Genetics, research has moved on. In 2008 we saw the publication of genome wide association studies for Bipolar disorder (Ferreira et al., 2008), for five dimensions of personality (Ter- racciano et al., 2008), ADHD (Neale et al., 2008) and major depressive disorder (Sullivan et al., 2008). Many more GWA studies of complex behavioral and psychiatric phenotypes are expected in the next few years. The landscape of behavior genetics has changed remarkably in a relatively short space of time. The field continues to progress from comparatively small studies to consortia-based efforts that target the inherited components of complex diseases and behaviors and which typically involve thousands of participants (Orr & Chanock, 2008).

References

Ferreira, M. A., O’Donovan, M. C., Meng, Y. A., Jones, I. R., Ruderfer, D. M., Jones, L., et al. (2008). Collaborative genome-wide association analysis supports a role for ANK3 and CACNA1C in bipolar disorder. Nature Genetics, 40, 1056Ð1058. Neale, B. M., Lasky-Su, J., Anney, R., Franke, B., Zhou, K., Maller, J. B., et al. (2008). Genome-wide association scan of attention deficit hyperactivity disorder. American Journal of Medical Genetics B Neuropsychiatric Genetics, 147B, 1337Ð1344. Orr, N., & Chanock, S. (2008). Common genetic variation and human disease. Advances in Genetics, 62, 1Ð32. Sullivan, P. F., de Geus, E. J. C., Willemsen, G., James, M. R., Smit, J. H., Zandbelt, T., et al. (2008). Genome-wide association for major depressive disorder: a possible role for the presynaptic protein piccolo. Molecular Psychiatry, 1Ð17. Terracciano, A., Sanna, S., Uda, M., Deiana, B., Usala, G., Busonero, F., et al. (2008). Genome-wide association scan for five major depressions of personality. Molecuar Psychiatry (in press). Acknowledgments

I gratefully acknowledge John DeFries, L. Erlenmeyer-Kimling, Irving Gottesman, Jenae Neiderhiser, Nancy Pedersen, and Anita Thapar who provided useful suggestions for shaping the contents of this handbook. I owe a great debt to my colleagues whose contributions create the substance of this exciting book. They have been very patient, and they have promptly responded and revised their chapters in light of reviewers’ comments and suggestions. I hope that they are as pleased with the final result as I am. I also acknowledge Janice Stern, my Springer Editor, for her patience on the long delay of the handbook, and I thank her staff for their help in publishing this book. I am especially grateful to the numerous colleagues who critically reviewed and improved the earlier versions of the chapters with very valuable comments and suggestions. These people include W. Anderson, J. Ando, R. Asarnow, H. Bleaut,« D. Blizzard, D. Boomsma, J. Bridle, D. Bruck, T. Button, A. Caspi, S. Cherny, K. Christensen, J. Crabbe, W. Crusio, K. Deater- Deckard, S. de Boer, C. DeCarli, J. DeFries, D. Dick, L. DiLalla, M. Dunne, L. Ehrman, T. Eley, L. Erlenmeyer-Kimling, W. Etges, J.-F. Ferveur, G. Fisch, B. Fish, J. Flint, S. Gammie, X. Ge, M. Geyer, N. Gillespie, J. Gleason, D. Gooding, I. Gottesman, T. Gould, P. A. Gowaty, E. Grigorenko, N. Harlaar, J. Harris, N. Henderson, J. Hewitt, A. Holmes, J. Horn, G. Jackson, J.-M. Jallon, K. Jang, J. Kaprio, W. Kates, J. Kuntsi, C. Kyriacou, R. Landgraf, J.-O. Larsson, L. Leve, J. Loehlin, M. Luciano, H. Maes, T. Markow, L. Matzel, S. Maxson, R. McCrae, S. McGuire, S. Medland, K. Morley, P. Mullineaux, J. Neiderhiser, R. Nelson, Y. Oguma, D. Overstreet, D. Patterson, S. Petrill, A. Pike, R. Pillard, R. Plomin, M. Pogue-Geile, G. Riedel, G. Rieger, F. Rijsdijk, J. Ringo, P. Roubertoux, M. Rutter, S. Smith, M. Stallings, T. Suzuki, G. Swan, P. Szatmari, M. Thomis, R. Todd, T. Verson, E. Viding, J. Vink, I. Weiner, H. Welzl, J. Wilson, D. Wolfer, and J. Young.

xi Contents

Introduction

1 History of Behavior Genetics ...... 3 John C. Loehlin

Part I Quantitative Methods and Models

2 Biometrical Models in Behavioral Genetics ...... 15 Michael C. Neale

3 QTL Methodology in Behavior Genetics ...... 35 Stacey S. Cherny

4 Multivariate Genetic Analysis ...... 47 Danielle Posthuma

5 Models of Human Behavior: Talking to the Animals ...... 61 Gene S. Fisch

Part II Genetics of Cognition

6 Twin Studies of General Mental Ability ...... 81 Nancy L. Segal and Wendy Johnson

7 Behavioral Genetic Investigations of Cognitive Aging ...... 101 Deborah Finkel and Chandra A. Reynolds

8 The Genetics and Environments of Reading: A Behavioral Genetic Perspective . 113 Sara A. Hart and Stephen A. Petrill

9 Behavior-Genetic and Molecular Studies of Disorders of Speech and Language: An Overview ...... 125 Elena L. Grigorenko

10 Human Brain Volume: What’s in the Genes? ...... 137 Jiska S. Peper, Marcel P. Zwiers, Dorret I. Boomsma, Rene« S. Kahn, and Hilleke E. Hulshoff Pol

xiii xiv Contents

11 Cognition in Rodents ...... 159 Christopher Janus, Michael J. Galsworthy, David P. Wolfer, and Hans Welzl

12 Neurogenetic Analysis and Cognitive Functions in Trisomy 21 ...... 175 Pierre L. Roubertoux and Michele` Carlier

13 Evolution of Complex Acoustic Signals in Drosophila Species ...... 187 Anneli Hoikkala and Dominique Mazzi

14 Drosophila Model of Alzheimer’s Amyloidosis ...... 197 Koichi Iijima, Kanae Iijima-Ando, and Yi Zhong

Part III Genetics of Personality

15 Genotype–Environment Correlation and Family Relationships ...... 209 Jennifer A. Ulbricht and Jenae M. Neiderhiser

16 Personality ...... 223 Kerry L. Jang and Shinji Yamagata

17 Molecular Genetics of Personality: How Our Genes can Bring Us to a Better Understanding of Why We Act the Way We Do ...... 239 Richard P. Ebstein and Salomon Israel

18 The Genetics of Childhood Temperament ...... 251 Jeffrey R. Gagne, Matthew K. Vendlinski, and H. Hill Goldsmith

19 Genetic and Environmental Influences on Sexual Orientation...... 269 Khytam Dawood, J. Michael Bailey, and Nicholas G. Martin

20 Some Guidelines for Defining Personality Differences in Rats ...... 281 Peter Driscoll, Alberto Fernandez-Teruel,« Maria G. Corda, Osvaldo Giorgi, and Thierry Steimer

21 The Genetics of Offensive Aggression in Mice ...... 301 Stephen C. Maxson

22 Sexual Selection and Aggressive Behavior in Drosophila ...... 317 Yong-Kyu Kim

23 Handedness: A Behavioral Laterality Manifestation ...... 331 Ira B. Perelle and Lee Ehrman

24 Genetics of Exercise Behavior ...... 343 Janine H. Stubbe and Eco J.C. de Geus

Part IV Genetics of Psychopathology

25 Genetics of ADHD, Hyperactivity, and Attention Problems ...... 361 Eske M. Derks, James J. Hudziak, and Dorret I. Boomsma Contents xv

26 Depression and Anxiety in Childhood and Adolescence: Developmental Pathways, Genes and Environment ...... 379 Frances Rice and Anita Thapar

27 Genetics of Autism...... 397 Sarah Curran and Patrick Bolton

28 Genetics of Smoking Behavior ...... 411 Richard J. Rose, Ulla Broms, Tellervo Korhonen, Danielle M. Dick, and Jaakko Kaprio

29 The Genetics of Substance Use and Substance Use Disorders ...... 433 Danielle M. Dick, Carol Prescott, and Matt McGue

30 Genetic Analysis of Conduct Disorder and Antisocial Behavior ...... 455 Soo Hyun Rhee and Irwin D. Waldman

31 Schizophrenia and Affective Psychotic Disorders – Inputs from a Genetic Perspective ...... 473 Daniel R. Hanson

32 Genetic Risks in Schizophrenia: Cross-National Prospective Longitudinal High-Risk Studies ...... 487 Judith G. Auerbach, L. Erlenmeyer-Kimling, Barbara Fish, Sydney L. Hans, Loring J. Ingraham, Joseph Marcus, Thomas F. McNeil, and Erland Schubert

33 Attention and Working Memory: Animal Models for Cognitive Symptoms of Schizophrenia – Studies on D2-Like Receptor Knockout Mice ...... 501 Claudia Schmauss

Conclusion

34 Future Directions for Behavior Genetics ...... 515 Yong-Kyu Kim

Index...... 519 Contributors

Judith G. Auerbach Department of Psychology, Ben-Gurion University, Beer-Sheva, Israel; Center for Advanced Studies, Norwegian Academy of Science and Letters, Oslo, Norway, Email: [email protected]

J. Michael Bailey Department of Psychology, Northwestern University, Evanston, IL 60637, USA, Email: [email protected]

Patrick F. Bolton Department of Psychologist Medicine, Institute of Psychiatry, London SE5 8AF, UK, Email: [email protected]

Dorret I. Boomsma Department of Biological Psychology, Vrije Universiteit, Amsterdam 1081 BT, The Netherlands, Email: [email protected]

Ulla Broms Department of Public Health, University of Helsinki, Helsinki 00014, Finland; Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland, Email: ulla.broms@helsinki.fi

Michele` Carlier Institut Universitaire de France and Laboratoire Psychologie Cognitive, UMR 6146, CNRS Aix-Marseille 1, Marseille Cedex 20, France, Email: [email protected]

Stacey S. Cherny Department of Psychiatry, Genome Research Centre, and The State Key, Laboratory of Brain and Cognitive Sciences, University of Hong Kong, Pokfulam, Hong Kong, Email: [email protected]

Maria G. Corda Department of Toxicology, University of Cagliari, Cagliari 09124, Italy, Email: [email protected]

Sarah Curran Department of Psychologist Medicine, Institute of Psychiatry, London SE5 8AF, UK, Email: [email protected]

Khytam Dawood Department of Psychology and Center for Developmental and Health Genet- ics, Pennsylvania State University, University Park, PA 16802, USA, Email: [email protected]

xvii xviii Contributors

Eco J.C. de Geus Department of Biological Psychology, Vrije Universiteit, Amsterdam 1081 BT, The Netherlands, Email: [email protected]

Eske M. Derks Department of Biological Psychology, Vrije Universiteit, Amsterdam 1081 BT, The Netherlands; University Medical Center Utrecht, Divisie hersenen, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands, Email: [email protected]

Danielle M. Dick Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA, Email: [email protected]

Peter Driscoll Institute for Animal Science, ETHZ, Schwerzenbach 8603, Switzerland, Email: [email protected]

Richard P. Ebstein Department of Psychology, Scheinfeld Center of Genetic Studies for the Social Sciences, Hebrew University of Jerusalem; Sarah Herzog Memorial Hospital, Givat Shaul, Jerusalem 91905, Israel, Email: [email protected]

Lee Ehrman School of Natural and Social Sciences, Purchase College, State University of New York, Purchase, NY 10577, USA, Email: [email protected]

L. Erlenmeyer-Kimling Departments of Medical Genetics, New York State Psychiatric Institute, New York, NY 10032, USA; Departments of Psychiatry and of Genetics and Development, Columbia University, New York, NY, USA, Email: [email protected]

Alberto Fernandez-Teruel´ Medical Psychology Unit, Department of Psychiatry and Forensic Medicine, University of Barcelona, Bellaterra 08193, Spain, Email: [email protected]

Deborah Finkel Department of Psychology, School of Social Sciences, Indiana University Southeast, New Albany, IN 47150, USA, Email: dfi[email protected]

Gene S. Fisch Bluestone Clinical Research Center, NYU Colleges of Dentistry & Nursing, Yeshiva University, New York, NY 10010, USA, Email: gene.fi[email protected]

Barbara Fish Department of Psychiatry and Behavioral Sciences, University of California, Los Angeles, CA 90095, USA, Email: bfi[email protected]

Jeffrey R. Gagne Department of Psychology, University of Wisconsin, Madison, WI 53706, USA, Email: [email protected] Contributors xix

Michael J. Galsworthy Division of Neuroanatomy and Behavior, Institute of Anatomy, University of Zurich, Zurich CH-8057, Switzerland, Email: mike [email protected]

Osvaldo Giorgi Department of Toxicology, University of Cagliari, Cagliari 09124, Italy, Email: [email protected]

H. Hill Goldsmith Department of Psychology, University of Wisconsin, Madison, WI 53706, USA, Email: [email protected]

Elena L. Grigorenko Child Study Center, Department of Psychology, Department of Epidemiology & Public Health, Yale University, New Haven, CT 06519-1124, USA, Email: [email protected]

Sydney L. Hans School of Social Service Administration, University of Chicago, Chicago, IL 60637, USA, Email: [email protected]

Daniel R. Hanson Departments of Psychiatry & Psychology, University of Minnesota, Minneapolis, MN 55454, USA, Email: [email protected]

Sara A. Hart Department of Human Development and Family Science, The Ohio State University, Columbus, OH 43210, USA, Email: [email protected]

Anneli Hoikkala Department of Biological and Environmental Science, University of Jyvaskyl¬ a,¬ Jyvaskyl¬ a,¬ Finland, Email: anneli.a.hoikkala@jyu.fi

James J. Hudziak Department of Psychiatry and Medicine (Division of Human Genetics), Center for Children, Youth and Families, University of Vermont, Burlington, VT, USA, Email: [email protected]

Hilleke E. Hulshoff Pol Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, The Netherlands, Email: [email protected]

Koichi Iijima Laboratory of Neurodegenerative Diseases and Gene Discovery; Farber Institute for Neurosciences; Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia PA19107, USA, Email: [email protected]

Kanae Iijima-Ando Laboratory of Neurogenetics and Pathobiology; Farber Institute for Neurosciences; Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia PA 19107, USA, Email: [email protected]

Loring J. Ingraham Department of Psychology, The George Washington University, Washington, DC 20037, USA, Email: [email protected] xx Contributors

Salomon Israel Department of Psychology, Scheinfeld Center of Genetic Studies for the Social Sciences, Hebrew University of Jerusalem, Jerusalem 91905, Israel, Email: [email protected]

Kerry L. Jang Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada, V6T 2A1. Email: [email protected]

Christopher Janus Mayo Clinic Jacksonville, Department of Neuroscience, University of Florida, Jacksonville, FL 32224, USA, Email: [email protected]

Wendy Johnson Centre for Cognitive Ageing and Cognitive Epidemiology and Department of Psychology, University of Edinburgh, Edinburgh, UK, and Department of Psychology, University of Minnesota, Minneapolis, MN 55455, USA, Email: [email protected]

Rene´ S. Kahn Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, The Netherlands, Email: [email protected]

Jaakko Kaprio Department of Public Health, University of Helsinki, Helsinki 14, Finland; Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland, Email: jaakko.kaprio@helsinki.fi

Yong-Kyu Kim Department of Genetics, University of Georgia, Athens, GA 30602, USA, Email: [email protected]

Tellervo Korhonen Department of Public Health, University of Helsinki, Helsinki 14, Finland; Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland, Email: tellervo.korhonen@helsinki.fi

John C. Loehlin Department of Psychology, University of Texas at Austin, Austin, TX 78712, USA, Email: [email protected]

Joseph Marcus Department of Psychiatry, University of Chicago, Chicago, IL 60637, USA, Email: [email protected]

Nicholas G. Martin Department of Genetic Epidemiology, Queensland Institute of Medical Research, Brisbane, Queensland, Australia, Email: [email protected]

Stephen C. Maxson Department of Psychology, University of Connecticut, Storrs, CT 06269- 1020, USA, Email: [email protected] Contributors xxi

Dominique Mazzi Institute of Plant Sciences, Swiss Federal Institute of Technology, Zurich, Switzerland, Email: [email protected]

Matthew McGue Department of Psychology, University of Minnesota, Minneapolis, MN 55455, USA; Department of Epidemiology, Southern Denmark University, Denmark, Email: [email protected]

Thomas F. McNeil Department of Psychiatric Epidemiology, University Hospital, Lund University, Israel, Email: [email protected]

Michael C. Neale Departments of Psychiatry and Human Genetics, Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA, Email: [email protected]

Jenae M. Neiderhiser Department of Psychiatry and Behavioral Sciences, Center for Family Research, The Pennsylvania State University, University Park, PA 16802, USA, Email: [email protected]

Jiska S. Peper Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, The Netherlands, Email: [email protected]

Ira B. Perelle Department of Psychology, Mercy College, Dobbs Ferry, NY 10522, USA, Email: [email protected]

Stephen A. Petrill Department of Human Development and Family Science, Ohio State University, Columbus, OH 43210, USA, Email: [email protected]

Danielle Posthuma Department of Biological Psychology, Section Medical Genomics, and Section Functional Genomics, Vrije Universiteit and Vrije Universiteit Medical Center, Amsterdam 1081BT, The Netherlands, Email: [email protected]

Carol Prescott Department of Psychology, University of Southern California, Los Angeles, CA 90089, USA, Email: [email protected]

Chandra A. Reynolds Department of Psychology, University of California, Riverside, CA 92521, USA, Email: [email protected]

Soo Hyun Rhee Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309, USA, Email: [email protected]

Frances Rice Child & Adolescent Psychiatry Section, Department of Psychological Medicine, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK, Email: [email protected] xxii Contributors

Richard J. Rose Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA; Department of Public Health, University of Helsinki, Finland, Email: [email protected]

Pierre L. Roubertoux INSERM UMR910 Gen« etique« Medicale« et Genomique« Fonctionnelle, Universite« d’Aix-Marseille 2, FacultedeM« edecine,« 27 Bvd Jean Moulin, 13385 Marseille Cedex 05, France, Email: [email protected]

Claudia Schmauss Department of Psychiatry and Molecular Therapeutics, Columbia University and New York State Psychiatric Institute, New York, NY 10032, USA, Email: [email protected]

Erland Schubert Department of Psychiatric Epidemiology, University Hospital, Lund University, Israel, Email: [email protected]

Nancy L. Segal Department of Psychology, California State University, Fullerton, CA 92834, USA, Email: [email protected]

Thierry Steimer Clinical Psychopharmacology Unit, University Hospital of Geneva, 1225 Chene-Bourg,ˆ Switzerland, Email: [email protected]

Janine H. Stubbe Department of Biological Psychology, Vrije Universiteit, Amsterdam 1081 BT, The Netherlands, Email: [email protected]

Anita Thapar Child & Adolescent Psychiatry Section, Department of Psychological Medicine, Cardiff University, Cardiff CF14 4XN, UK, Email: [email protected]

Jennifer A. Ulbricht Center for Family Research; Department of Psychology, George Washington University, Washington, DC 20037, USA, Email: [email protected]

Matthew K. Vendlinski Department of Psychology, University of Wisconsin, Madison, WI 53706, USA, Email: [email protected]

Irwin D. Waldman Department of Psychology, Emory University, Atlanta, GA 30322, USA, Email: [email protected]

Hans Welzl Division of Neuroanatomy and Behavior, Institute of Anatomy, University of Zurich, Zurich CH-8057, Switzerland, Email: [email protected]

David P. Wolfer Division of Neuroanatomy and Behavior, Institute of Anatomy, University of Zurich, Zurich CH-8057, Switzerland, Email: [email protected] Contributors xxiii

Shinji Yamagata Faculty of Letters, Keio University, Tokyo, 108-8345, Japan, Email: [email protected]

Yi Zhong Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA, Email: [email protected]

Marcel P. Zwiers F.C. Donders Center for Cognitive Neuroscience, Nijmegen, The Netherlands; Psychiatry Department, Radboud University, Nijmegen Medical Center, Nijmegen 6525 HE, The Netherlands, Email: [email protected] Introduction Chapter 1 History of Behavior Genetics

John C. Loehlin

Hermann Ebbinghaus (1908) said of psychology that it had a Greeks, Romans, Hebrews long past, but only a short history. The same may be said of behavior genetics. One cannot specify an exact date at which By classical times, 3000Ð1500 years ago, many varieties of behavior genetics came to be regarded as a distinct scientific dogs with distinctive physical and behavioral characteristics discipline, but for convenience let us say 1960, the publica- were recognized. More than 50 breeds are named in sur- tion date of Fuller and Thompson’s textbook of that title. viving Greek and Roman documents, falling into such cate- This chapter considers both the long past and some gories as scent- and sight hounds, shepherd dogs, guard dogs, aspects of the short history of behavior genetics. We begin war dogs, and pets (Brewer et al., 2001). with the long past: the recognition since antiquity that behav- The ancient Greeks held that humans inherited quali- ioral traits are in part inherited, and the controversy concern- ties, including behavioral ones, from their ancestors. Thus ing the extent to which this is so, a discussion often going in Book IV of Homer’s Odyssey, Menelaus greets two young under the label of the nature–nurture controversy. visiting strangers, “Ye are of the line of men that are scep- tred kings ... for no churls could beget sons like you” (Homer, trans. 1909, p. 49). And later (p. 53), to one of them, “Thou has said all that a wise man might say or do, yea, and The Long Past of Behavior Genetics an elder than thou; Ð for from such a sire too thou art sprung, wherefore thou dost even speak wisely.” A similar notion From Ancient Times to the Renaissance was expressed in the Hebrew scriptures: “I am the heir of wise men, and spring from ancient kings” (Isaiah 19:11, New English Bible). Ancient Times A few hundred years later, the Greek philosopher Plato in Book V of the Republic Ð his prescription for an ideal Where does the long past start? Perhaps with the domes- state Ð took both inheritance and instruction into account tication of dogs for behavioral as well as physical traits, in the development of the “Guardians,” the ruling elite. He a process which probably took place at least 15,000 years begins with the question, “How can marriages be made most ago (Savolainen, Zhang, Luo, Lundeberg, & Leitner, 2002) Ð beneficial?” He discusses the breeding of hunting dogs and although one must suppose that in its early days this was birds, noting that “Although they are all of a good sort, are more an evolution of a subgroup of wolves to fit a niche not some better than others?” “True.” “And do you breed around human habitation than a process deliberately under- from them all indifferently, or do you take care to breed from taken by man (Morey, 1994). In any case, about 5000 years the best only?” “From the best” (Plato, trans. 1901, p. 149). ago in Egypt and the Near East, it appears that deliber- From there Plato goes on to generalize to the class of elite ate animal breeding was well established (Brewer, Clark, & humans in his ideal state Ð to the desirability of matching the Phillips, 2001); several distinctive varieties of cattle and dogs best with the best, and rearing their offspring with special are portrayed in ancient Egyptian art. attention. Plato recognizes that good ancestry is not infallibly pre- dictive and recommends applying, at least in early youth, a universal education to the citizens of his state; demoting, when inferior, offspring of the elite class of guardians and J.C. Loehlin (B) Department of Psychology, The University of Texas at Austin, Austin, elevating into the ranks of the guardians offspring of the TX 78712, USA lower classes who show merit.

Y.-K. Kim (ed.), Handbook of Behavior Genetics, 3 DOI 10.1007/978-0-387-76727-7 1, c Springer Science+Business Media, LLC 2009 4 J.C. Loehlin

We need not debate the pros and cons of Plato’s partic- entered into for the common good, had an immense influence ular social proposals; people have been arguing about them via Jefferson, Voltaire, Rousseau, and the other theorists of ever since his day. We only need observe that well over 2000 the American and French revolutions. years ago the interplay of nature and nurture Ð and its social Indeed, one may view many of the events of the natureÐ implications Ð was being discussed. nurture controversy since Locke’s day as a series of chal- lenges to the prevailing Lockean position, with those steeped in that tradition rising indignantly to battle what they per- Middle Ages ceived to be threats to inalienable human rights of liberty and equality. What of the contrary view, the notion that all men are Locke himself, however, was not nearly as alien to hered- born equal? A major impetus to such an idea came from itarian concepts as some of his followers have been. He the medieval Catholic Church (Pearson, 1995). All men are rejected the concept of inborn ideas, but not of all innate char- sons of God, and therefore of equal value in His sight. Or, acteristics. In a marginal note on a pamphlet by one Thomas from another perspective, as the fourteenth-century English Burnet, Locke wrote “I think noe body but this Author who proverb had it, “When Adam delved and Eve span/Who was ever read my book [An Essay Concerning Human Under- then a gentleman?” standing] could doubt that I spoke only of innate Ideas ... and not of innate powers ...” (see Porter, 1887). Elsewhere in Some Thoughts Concerning Education Locke wrote, The Renaissance Some Men by the unalterable Frame of their Constitutions are stout,otherstimorous,someconfident,othersmodest, tractable, Ideas concerning the inheritance of behavior were present in or obstinate, curious or careless, quick or slow. There are not Shakespeare’s day. The Countess of Rossilon in All’s Well more Differences in Men’s Faces, or in the outward Lineaments That Ends Well says, about a wise daughter of a wise father, of their Bodies, than there are in the Makes and Tempers of their Minds. (1693/1913, Sect. 101) “Her dispositions she inherits” (Act I:i). The natureÐnurture controversy itself appears to have got its label from Pros- pero’s remark in The Tempest about his subhuman creature, John Stuart Mill Caliban, “A devil, a born devil, on whose nature nurture will never stick” (Act IV:i). Many of Locke’s successors in the English liberal tradition came out more strongly than Locke did on the side of nurture. John Stuart Mill wrote in his Autobiography (1873, p. 192), The Nature–Nurture Controversy in the I have long felt that the prevailing tendency to regard all the Modern Era marked distinctions of human character as innate, and in the main indelible, and to ignore the irresistible proofs that by far the greater part of these differences, whether between individuals, Although ideas about the roles of nature and nurture in races, or sexes, are such as not only might but naturally would human and animal behaviors have been with us for thousands be produced by differences in circumstances, is one of the chief of years, the modern form of the controversy traces back hindrances to the rational treatment of great social questions, and fairly directly to the seventeenth-century philosopher John one of the greatest stumbling blocks to human improvement. Locke and the nineteenth-century naturalist Charles Darwin.

Charles Darwin John Locke During roughly the same period as Mill, Charles Darwin Locke may be considered to be the chief ideological father gave the nature side of the controversy its modern form of the nurture side of the controversy. In An Essay Concern- by placing behavior, including human behavior, solidly in ing Human Understanding (Locke, 1690/1975), he invoked the framework of biological evolution. In addition to his the metaphor of the mind as a blank sheet of paper upon major treatise The Origin of Species (1859), Darwin in such which knowledge is written by the hand of experience. In the works as The Descent of Man (1871) and The Expression opening paragraph of his book Some Thoughts Concerning of the Emotions in Man and Animals (1872) made it clear Education, he said, “I think I may say, that of all the Men that human behavior shared ancestry with that of other ani- we meet with, nine Parts of ten are what they are, good or mal forms, and was subject to the same evolutionary pro- evil, useful or not, by their Education” (Locke, 1693/1913, cess of hereditary variation followed by natural selection of Sect. 1). Locke’s political view that all men are by nature the variants that proved most successful in their particular equal and independent, and that society is a mutual contract environments. 1 History of Behavior Genetics 5

In The Descent of Man (1871, pp. 110Ð111) Darwin one at random and train him to become any type of specialist wrote, I might select Ð doctor, lawyer, artist, merchant-chief, and yes, even beggar-man and thief, regardless of his talents, penchants, So in regard to mental qualities, their transmission is manifest tendencies, abilities, vocations, and race of his ancestors. in our dogs, horses, and other domestic animals. Besides special tastes and habits, general intelligence, courage, bad and good temper, etc. are certainly transmitted. With man we see simi- The year 1928 saw the publication of the Twenty-Seventh lar facts in almost every family; and we now know through the admirable labours of Mr. Galton that genius, which implies a Yearbook of the National Society for the Study of Educa- wonderfully complex combination of high faculties, tends to be tion. It was entitled Nature and Nurture, and it contained inherited; and on the other hand, it is too certain that insanity and the reports of two adoption studies of IQ. One, by Barbara deteriorated mental powers likewise run in the same families. Burks, emphasized the effects of nature. The other, by Free- man, Holzinger, and Mitchell, came down on the side of nurture. The natureÐnurture controversy continued, but stu- Francis Galton dents of the effects of heredity and environment on behavior were gathering data. When enough had been gathered for a Darwin’s younger cousin Francis Galton agreed with Darwin textbook to be written, the short history of behavior genetics and disagreed with Mill. In his book Inquiries into Human could begin. Faculty (1883, p. 241) he concluded, There is no escape from the conclusion that nature prevails enor- mously over nurture when the differences of nurture do not exceed what is commonly to be found among persons of the same rank of society and in the same country. The Short History of Behavior Genetics Galton is not saying that environment never matters. How- ever, he is saying that the ordinary differences we observe Most of the short history of behavior genetics, as it applies among people in the same general social context are mostly to the study of both humans and other animal species, will due to heredity. not be discussed in this chapter. It is a tale of steady sci- Galton was a central, crystallizing figure in behavior entific progress on a variety of fronts, despite occasional genetics’ “long past.” His emphasis on the measurement of controversies, confusions, and setbacks, and it is a tale told individual differences and their statistical treatment became in the other chapters of this handbook. The reader who wants a core theme in the development of the field. His studies a quick sense of the scope of scientific progress in the field of “hereditary genius” and “the comparative worth of differ- of behavior genetics during the last 40-odd years, and the ent races” (Galton, 1869) foreshadowed recent controversies prospects opening up in it today, can achieve this by scanning about IQ. He proposed the study of twins as a way of getting through the chapter introductions and summaries, and the at the relative effect of nature and nurture. And his promotion editor’s final chapter. The reader who aspires to a more solid of eugenics Ð that is, the encouragement of the more useful grasp of this short history will need, of course, to proceed members of society to have more children and the less useful more systematically through the book, as well as following to have fewer (as in Plato’s scheme for an ideal state) Ð has up some of its many references. generated on occasion a good deal of heat. Here is a recent The remainder of this chapter addresses two other aspects example (Graves, 2001, p. 100): “Galton’s scientific accom- of behavior genetics’ short history. First, we look briefly at plishments are sufficient for some still to consider him an some institutional features of the field: its principal schol- intellectual hero. Whereas for others (this author included) arly and scientific organization, the Behavior Genetics Asso- he was an intellectual mediocrity, a sham, and a villain.” ciation; the discipline’s key journal, Behavior Genetics; and some major centers of behavior genetics research. Following this, we look at the social context of behavior genetics, at The Twentieth Century instances in which the scientific and scholarly pursuits of the field have become entangled with public political and social Vigorous disagreements on the relative impact of nature and concerns. These instances include a series of controversies nurture on behavior continued into the twentieth century. On concerning the genetic or environmental bases of differences the whole, twentieth-century psychology was heavily envi- in psychological characteristics between groups defined by ronmentalistic, emphasizing the crucial role of learning in race, sex, or social class. Controversies about group differ- shaping behavior. The high-water mark of this tradition was ences have roots in behavior genetics’ long past and have the famous claim of John B. Watson (1925, p. 82): persisted into its short history. They are far from central in Give me a dozen healthy infants, well-formed, and my own spec- the activities of most working behavior geneticists, but they ified world to bring them up in and I’ll guarantee to take any represent an important part of the public face of the field. 6 J.C. Loehlin

The Institutional History of Behavior Genetics Table 1.1 BGA Presidents and Annual Meetings Year President Site of meeting The Behavior Genetics Association 1971 R. H. Osborne [pro tem] Storrs CT 1972 Th. Dobzhansky Boulder CO 1973 John L. Fuller Chapel Hill NC After some informal discussions in the late 1960s, and the 1974 Gerald E. McClearn Minneapolis MN circulation of a mailing to a list of persons who had recently 1975 J. P. Scott Austin TX published in the area of behavior genetics, an organizational 1976 Irving I. Gottesman Boulder CO meeting took place at Urbana, Illinois, in March 1970. R. 1977 W. R. Thompson Louisville KY 1978 Lee Ehrman Davis CA H. Osborne, then editor of the journal Social Biology,was 1979 V. Elving Anderson Middletown CT chosen to act as president pro tem, and five committees were 1980 John C. Loehlin Chicago IL appointed to lay the groundwork for a Behavior Genetics 1981 Norman D. Henderson Purchase NY/Jerusalem Association (or Society Ð there was some argument about 1982 John C. DeFries Ft Collins CO 1983 David W. Fulker London, England a suitable name). In April 1971, the fledgling organization 1984 Steven G. Vandenberg Bloomington IN held its first formal meeting, at Storrs, Connecticut. In addi- 1985 Sandra Scarr State College PA tion to scientific sessions, a draft constitution was discussed 1986 Ronald S. Wilson Honolulu HI to be submitted to the initial membership via mail ballot for 1987 Peter A. Parsons Minneapolis MN 1988 Leonard L. Heston Nijmegen, Netherlands approval. Nominations and an election followed, and at the 1989 Robert Plomin Charlottesville VA time of the second annual meeting at Boulder, Colorado, 1990 Carol B. Lynch Aussois, France in April 1972, the Behavior Genetics Association (BGA) 1991 Lindon J. Eaves St. Louis MO was officially underway, and its first set of officers took 1992 David A. Blizard Boulder CO 1993 Thomas J. Bouchard, Jr. Sydney, Australia office: Theodosius Dobzhansky was president, John Fuller 1994 Glayde Whitney Barcelona, Spain was president-elect, R. H. Osborne served as past president, 1995 James Wilson Richmond VA the secretary was Elving Anderson, the treasurer was John 1996 Nicholas G. Martin Pittsburgh PA Loehlin, and the two executive committee members-at-large 1997 Nicholas G. Martin Toronto, Canada 1998 Norman D. Henderson Stockholm, Sweden were Seymour Kessler and L. Erlenmeyer-Kimling. 1999 Richard Rose Vancouver, Canada The association proved viable. Table 1.1 shows the suc- 2000 John Hewitt Burlington VT cessive presidents of the BGA and the location of its annual 2001 Matt McGue Cambridge, England meetings. Note that a special extra international meeting was 2002 Nancy Pedersen Keystone CO 2003 Andrew Heath Chicago IL held in Jerusalem in 1981, and that thereafter the regular 2004 Michele` Carlier Aix-en-Provence, France annual BGA meeting was periodically held in countries out- 2005 H. Hill Goldsmith Hollywood CA side the USA: in England (twice), the Netherlands (twice), 2006 Laura Baker Storrs CT France, Australia, Spain, Canada (twice), and Sweden. 2007 Pierre Roubertoux Amsterdam, Netherlands Over time, the association grew in size. Forty-four persons Source: BGA web site (June 27, 2007); http://www.bga.org responded to the initial mailing indicating interest in such an association. There were 69 paid-up members at the time of genetics have thus been published in widely scattered journals, a the first annual meeting at Storrs. By the time of the 34th clear identification with this discipline has been lacking. It is our annual meeting in Aix-en-Provence, France, in 2004, the hope that BEHAVIOR GENETICS will fulfill this need. BGA had 270 regular and 109 associate members (the latter chiefly graduate students). Approximately two-thirds were The journal has largely lived up to their hopes. It never from North America and one-third from other continents. stood completely alone Ð for example, at the time there was an existing journal focused on twin research, Acta Geneticae Medicae et Gemellologiae, which published many behav- The Journal Behavior Genetics iorally oriented papers. The journal Social Biology Ð whose editor, R. H. Osborne, played an important role in found- In 1970, a decade after Fuller and Thompson’s textbook, the ing the Behavior Genetics Association Ð initially served as scientific journal Behavior Genetics began with Vol. 1, No. 1. the official organ of the BGA. (Behavior Genetics assumed Its founding editors were Steven G. Vandenberg and John C. that role in 1974.) Other journals have since emerged Ð DeFries. They stated their hopes for the new journal in an for example, the recent journals Genes, Brains, and Behav- editorial (p. 1): ior and Twin Research. Many important papers in behavior genetics continue to be published in journals in the neighbor- Research in behavior genetics continues to be undertaken at ing behavioral and biological sciences. Nevertheless, Behav- an accelerating rate. Nevertheless, no single journal has existed heretofore which was dedicated primarily to the publication of ior Genetics, as the official organ of the Behavior Genetics papers in this important area. Since manuscripts in behavior Association, remains a major defining force in the field. 1 History of Behavior Genetics 7

It is instructive to compare Vol. 1 (1970) of Behavior important U.S. centers include Washington University in Genetics with Vol. 35 (2005). The journal became a good St. Louis (Robert Cloninger, Andrew Heath, & John Rice) deal bigger: from three issues in Vol. 1 (Nos. 3 and 4 were and Penn State (David Blizard, Gerald McClearn, & George bound together) to six in Vol. 35 from 274 to 854 pages Vogler). Outside the USA, Kings College, London, has (and nearly twice the number of words per page because recruited an eminent group of behavior genetics researchers, of larger pages). In Vol. 1, there were 24 papers, an edito- including Peter McGuffin, Robert Plomin, and Michael Rut- rial, and 2 “short communications.” In Vol. 35 there were ter. The Vrije Universiteit in Amsterdam also has a substan- 66 papers, plus 142 abstracts from the Behavior Genetics tial behavior genetics contingent, including Dorret Boomsma Association meeting, and various BGA minutes, announce- and Danielle Postuma. Stable international coalitions are ments, etc. Behavior Genetics continues to publish both sub- becoming increasingly common, greatly facilitated by the stantively and methodologically oriented papers, featuring Internet. Notable examples include collaborations between various animal species, but the mix changed from Vol. 1 groups at Indiana University and the University of Helsinki, to Vol. 35. In Vol. 1 there were 7 papers (27%) focused on Penn State and the Karolinska Institute in Stockholm, and human behavior, 16 papers (62%) involving rodents, mostly several U.S. groups with the Queensland Institute for Medi- inbred mice, 1 paper on another species (Drosophila), and cal Research in Australia. 2 papers primarily methodological (statistical) in character. Beside the institutions mentioned above, dozens of other In Vol. 35, there was an increased proportion of substantive universities and research institutes, including many outside papers involving humans, 28 (42%); proportionately fewer the USA, have developed and maintained strong programs involving rodents, 14 (21%); an increase in those involving in human or animal behavior genetics on the strength of one other animal species, 9 (15%) Ð mostly Drosophila, but one or two distinguished researchers on their faculties. Almost on rainbow trout. For many of the remaining 22% of papers, half the presidents of the BGA, for example, would represent the species might be described as the computer: These were this category. The hosting of an annual BGA meeting (see methodological papers, many involving a heavy dose of com- Table 1.1) also tends to reflect a strong local program. puter model-fitting or simulation.

Major Behavior Genetics Centers Public Controversies – Group Differences

Preeminent among academic centers for teaching and The possibility that there might be genetic differences in research in behavior genetics has been the Institute for psychological traits between groups defined by race, sex, or Behavioral Genetics (IBG) at the University of Colorado at social class has led to a good deal of public uproar and not Boulder. Among the notable behavior geneticists who have a little confusion. It has provided an inflammatory intersec- served on its faculty are Gregory Carey, John DeFries, David tion between the scientific discipline of behavior genetics Fulker, John Hewitt, Carol Lynch, Gerald McClearn, Robert and Western attitudes of equality stemming from religious, Plomin, Steven Vandenberg, and James Wilson. It has also political, and philosophical roots. Racist, sexist, and class- served as home for the journal Behavior Genetics, except for ist ideas (as references to such group differences are some- 1978Ð1985 when Jan Bruell edited the journal at the Uni- times called) tend to drive traditional Lockean ideologists up versity of Texas and 2000Ð2002 when Norman Henderson the wall, so that clear thinking has not always prevailed in edited it at Oberlin College. The IBG has also hosted sev- this area. eral BGA annual meetings and a number of summer training A few general points should be noted. First, the main institutes on behavior genetics methods. business of behavior geneticists has always been individual Next in line as a center of behavior genetics activity would differences, not group differences, so that for the day-to-day probably be the University of Minnesota, whose faculty has research of most behavior geneticists, questions about group included important behavior geneticists like Elving Ander- differences are at best an unwelcome distraction. Second, as son, Thomas Bouchard, Irving Gottesman, Leonard Heston, Lewontin (1970) made clear, a demonstration that individ- Gardner Lindzey, David Lykken, Matthew McGue, Shel- ual differences are due to genes does not imply that group don Reed, Sandra Scarr, and Auke Tellegen. A third cen- differences are genetic. He used the analogy of genetically ter, at least in the early days, was the University of Texas varied seeds raised in a greenhouse in two pots under iden- at Austin, with Jan Bruell, Joseph Horn, Gardner Lindzey, tical regimens, except that one pot lacked a crucial trace John Loehlin, Delbert Thiessen, and Lee Willerman. A cur- nutrient present for the other. The heights of the plants rent major behavior genetics center is at the Virginia Com- are subsequently measured. The variation of height within monwealth University; its faculty includes Lindon Eaves, each pot, except for random measurement errors, is entirely Kenneth Kendler, Hermine Maes, and Michael Neale. Other genetic, since the plants within each pot vary genetically, 8 J.C. Loehlin but are treated exactly the same. The average difference in meetings disrupted. A graphic account of the goings-on may plant height between the two pots is entirely environmen- be found in Pearson (1991). The controversy about possible tal, because it stems from the presence or absence of the racial differences in mental abilities has continued to the critical nutrient. Clearly, this example implies that group present Ð the interested reader may wish to consult Race differences may be different in their genetic and environ- Differences in Intelligence (Loehlin et al., 1975), Race, IQ mental origins from individual differences. However, it is and Jensen (Flynn, 1980), The Black–White Test Score Gap sometimes forgotten that may does not imply are. There (Jencks & Phillips, 1998), and The New Know-Nothings remains the empirical question for any particular trait and (Hunt, 1999). Rushton and Jensen (2005) provide a recent any particular group difference in any particular population: review emphasizing the genes: “Thirty years of research on To what relative extent are genetic and environmental dif- race differences in cognitive ability,” which, along with a ferences between the groups in fact involved? There also number of critiques from various points of view, fills an issue remains the social question: How much (if at all) does this of Psychology, Public Policy, and Law [Vol. 11(2), 2005]. matter? The empirical question is not necessarily an easy one to The Bell Curve answer. For one thing, it may well have different answers for different traits and different groups (Loehlin, 2000). If one Twenty-five years after Jensen’s article, a similar uproar were to demonstrate that profiles of cognitive ability differ arose, this time due to the publication of a book by the for genetic reasons between Asian Americans and European psychologist Richard Herrnstein and the sociologist Charles Americans, it would not imply that a difference in average Murray entitled The Bell Curve (Herrnstein & Murray, 1994). intellectual performance between European Americans and Although much of the furor focused on race differences in African Americans has a genetic origin. To make matters cognitive skills, the authors did not in fact devote a great deal worse, the social excitement and media hoopla surrounding of attention to this topic and took a fairly mild position on the issue of group differences has discouraged most behav- it. After emphasizing via a version of Lewontin’s metaphor ior geneticists from addressing such matters empirically. It is that a genetic basis for individual differences does not imply not as though informative research designs do not exist. One a genetic basis for group differences, they said of U.S. ethnic listing of promising areas of research on racial-ethnic ability differences in average IQ (p. 312): differences listed ten possible approaches, ranging from stud- ies of race mixtures and cross-racial adoptions to piggy-back They may well include some (as yet unknown) genetic compo- nent, but nothing suggests that they are entirely genetic. And, studies on educational or nutritional programs which were most important, it matters little whether the genes are involved being undertaken for other reasons (Loehlin, Lindzey, & at all. Spuhler, 1975, pp. 251Ð254). Their argument in support of the second sentence was that for an appropriate treatment of an individual it is his or her own IQ that is relevant (if IQ is relevant at all), not the aver- Jensen age IQs of some group to which the individual may belong. One might add, however, that for long-term social policy, the Less than a decade into behavior genetics’ short history, fact that an average group difference has its source in genes the educational psychologist Arthur Jensen published a or in the environment can sometimes matter, because it can long article in the Harvard Educational Review entitled affect the choice of a remedy to alter that difference Ð eugen- “How much can we boost IQ and scholastic achievement?” ics versus Head Start, for example. (Jensen, 1969). Jensen noted the fact that compensatory education programs had not lived up to their advance billing and concluded that this might partly reflect the genetic Herrnstein on Social Class and IQ contribution to IQ, which he estimated at a fairly high 80%. Almost in passing, he noted the possibility that the The Bell Curve did not represent Herrnstein’s first engage- persistent IQ gap between U.S. blacks and whites might ment with group differences and public controversy. In an in part be genetic in origin. He did not say that this had article in The Atlantic (Herrnstein, 1971) and in a subsequent been demonstrated to be the case, but suggested that the book, I.Q. in the Meritocracy (1973), Herrnstein elaborated matter should be looked into empirically. Jensen’s article, on an idea by Cyril Burt (1961) that social class and occu- particularly the suggestion that there might be a genetic pational differences in IQ will be partly genetic in a soci- contribution to blackÐwhite IQ differences, created an ety that features social mobility. If IQ is partly genetic, and immediate furor. There were numerous published critiques, higher IQ individuals tend to move up in social and occupa- not all judicious and carefully thought out. And this was not tional status, while lower IQ individuals tend to move down, just a genteel academic debate Ð tires were slashed and public then IQ differences between social classes and occupational 1 History of Behavior Genetics 9 groups will come to be partly genetic. This is not a heredi- clearly right about the difficulty of public discussion of such tary aristocracy Ð far from it Ð it is a dynamic phenomenon questions. An announcement was issued the next day by the that depends on continued mobility up and down the social BGA Executive Committee to the effect that Whitney was scale. An important question is, How much? Some evidence not acting as the official spokesman of the association, that suggests that about 40% of IQ differences in occupation and presentations at BGA meetings should be strictly scientific, income in Western societies are associated with genetic dif- and that “members are not encouraged to express their per- ferences (Rowe, Vesterdal, & Rodgers, 1998; Tambs, Sundet, sonal political and moral views” (Heath, 1995, p. 590). A Magnus, & Berg, 1989). Phenotypically, there are substan- special December meeting of the BGA Executive Committee tial average differences in IQ between different occupational was scheduled to consider removing Whitney from the BGA groups. For example, in the U.S. standardization sample for Board of Directors, of which he was automatically a member the 1981 revision of the Wechsler Adult Intelligence Scale, as past president (e-mail announcement to the BGA member- there was a 22-point difference between the average IQs of ship, October 12, 1995). President-elect Pierre Roubertoux persons in professional and technical occupations and per- and Wim Crusio, a member-at-large of the Executive Com- sons who were unskilled laborers (Reynolds, Chastain, Kauf- mittee, resigned from the association because it was unwill- man, & McLean, 1987). And yet there was nearly as much ing to adopt sufficiently strong sanctions against Whitney. variation in IQ within these two occupational groups (stan- The incoming president-elect, Nicholas Martin, took over dard deviations of 14.4 and 15.2) as in the U.S. population for Roubertoux as president, and later served his own term, as a whole (standard deviation of 15.1). It is an interesting accounting for his double appearance in Table 1.1, in 1996 paradox that there may be real and significant differences in and 1997 (Heath, 1996). average IQ between different groups, yet individuals vary so widely within them that an individual’s group membership is of almost no value for predicting his or her IQ. Lawrence Summers and Sex Differences

On January 14, 2005, Harvard President Lawrence H. Sum- The Glayde Whitney Affair mers informally addressed a conference on “Diversifying the Science and Engineering Workforce” which was considering In his 1995 presidential address to the Behavior Genetics the reasons for a shortage of women at the highest levels in Association, Glayde Whitney, whose distinguished research the scientific professions (Summers, 2005). With the avowed career had mostly focused on taste sensitivity in mice, turned intention of provoking discussion, Summers proposed three to humans and elected to address the topic of blackÐwhite hypotheses for his audience’s consideration: (a) Many tal- differences in the frequency of criminal behavior. He pointed ented women prefer devoting some of their time to children out the large discrepancies on the phenotypic level, such as and families rather than undertaking the 80-hour work-weeks a ninefold difference in murder rates between blacks and required for reaching the top levels in elite research organi- whites in the USA. Compared to a dozen other industrialized zations; (b) there may be biological differences between the countries, the USA had the highest overall murder rate. How- sexes, such as a greater variance for males on many traits, ever, based only on its white population, it ranked third from producing an excess of males at the extremes; and (c) subtle the bottom, with a lower murder rate than such countries and not-so-subtle patterns of discrimination may exist that as Switzerland, Denmark, Finland, and Sweden. Whitney lead the present elite in these fields, mostly males, to choose argued that behavior geneticists should be willing to explore others like them to join them. Summers thought it likely that both genetic and environmental hypotheses about such dif- all three of these factors contributed, and he guessed that ferences; he also argued that the current intellectual climate they might rank in importance in the order given. Summers in the USA made such discussion virtually impossible Ð and is an economist by training, not a behavior geneticist, but he he made some critical remarks about the contribution of the cited some behavior genetic evidence against an overwhelm- political Left to this situation (Whitney, 1995). ing role of socialization in producing behavioral differences, Whitney’s address was perhaps not a model of tact: for and suggested that the effects in hypotheses (a) and (b) might example, in addition to his comments about the Left, he have in part a biological basis. Summers’ remarks aroused a noted that Richmond, Virginia, the city in which he was firestorm in the press and in feminist circles, which in turn speaking as a guest, was the second-worst large city in the provoked assorted indignant rejoinders. It is not necessary to USA with respect to its murder rate. Nor did he address pursue these in detail here Ð a quick survey on the Internet the question of how behavior geneticists were to go about will yield an ample sampling of widely varying views about deciding to what extent the group differences in criminality Summers’ remarks Ð views expressed with widely varying were genetic or environmental. Subsequent events within the degrees of heat and light. Pinker (2002, Chap. 18) provides Behavior Genetics Association proved, however, that he was a readable survey of the considerable evidence that at least 10 J.C. Loehlin some maleÐfemale psychological differences have a biolog- Flynn, J. R. (1980). Race, IQ and Jensen. London: Routledge & Kegan ical component Ð although, presumably, few are exclusively Paul. so, and many questions remain open empirically. Freeman, F. N., Holzinger,K. J., & Mitchell, B. C. (1928). The influence of environment on the intelligence, school achievement, and conduct of foster children. In 27th Yearbook of the National Society for the The Future? Study of Education, Part 1, pp. 103Ð217. Fuller, J. L., & Thompson, W. R. (1960). Behavior genetics.NewYork: Wiley. One take-home lesson from the various controversies con- Galton, F. (1869). Hereditary genius: An inquiry into its laws and con- cerning group differences is that the natureÐnurture contro- sequences. London: Collins. Galton, F. (1883). Inquiries into human faculty and its development. versy is not dead, even though it has been declared moribund London: Macmillan. on many occasions in recent decades. Although behavior Graves, J. L., Jr. (2001). The emperor’s new clothes: Biological theories geneticists have had an appreciable impact on public think- of race at the millennium. New Brunswick, NJ: Rutgers University ing about individual differences, the question of the relative Press. Heath, A. C. (1995). Secretary’s report: The 25th annual meeting of genetic and environmental contributions to group differences the Behavior Genetics Association, Richmond, Virginia. Behavior has been both more socially explosive and much less suc- Genetics, 25, 589Ð590. cessfully addressed empirically. Heath, A. C. (1996). Secretary’s report: The 26th annual meeting of What does the future hold? This will depend, in part, on the Behavior Genetics Association, Richmond, Virginia [Pittsburgh, Pennsylvania]. Behavior Genetics, 26, 605Ð606. future behavior genetics research on these topics Ð some of Herrnstein, R. J. (1971). I.Q. Atlantic Monthly 228(3), 43Ð64. it, perhaps, carried out by readers of this book. One may Herrnstein, R. J. (1973). I.Q. in the meritocracy. Boston: Little, Brown. be fairly confident that natureÐnurture controversies will not Herrnstein, R. J., & Murray, C. (1994). The bell curve: Intelligence and vanish completely anytime soon. However, one may hope class structure in American life. New York: The Free Press. Homer. (n.d./1909). The Odyssey (S. H. Butcher & A. Lang, Trans.). that as knowledge expands, the cloud of misunderstandings New York: Collier. on which these controversies feed will gradually shrink, and Hunt, M. (1999). The new know-nothings. New Brunswick, NJ: Trans- that one day we may have an agreed-upon body of facts on action Publishers. which to base social policy. Jensen, A. R. (1969). How much can we boost IQ and scholastic achievement? Harvard Educational Review, 39, 1Ð123. Jencks, C., & Phillips, M. (Eds.) (1998). The Black-White test score gap. Washington, DC: Brookings Institution. Conclusion Lewontin, R. C. (1970). Race and intelligence. Bulletin of the Atomic Scientists, 26(3), 2Ð8. Locke, J. (1690/1975). An essay concerning human understanding Yes, behavior genetics has had a long past, which extends (P. H. Nidditch, Ed.). Oxford: Clarendon Press. into the natureÐnurture controversies of the present day. It Locke, J. (1693/1913). Some thoughts concerning education (R. H. has also had a short but solid history of substantive accom- Quick, Ed.). Cambridge: Cambridge University Press. plishment and institutional establishment. The date at which Loehlin, J. C. (2000). Group differences in intelligence. In R. J. Stern- berg (Ed.), Handbook of intelligence (pp. 176Ð193). Cambridge: the short history will make the long past seem quaint and Cambridge University Press. obsolete in the eyes of the general educated public remains Loehlin, J. C., Lindzey, G., & Spuhler, J. N. (1975). Race differences in to be determined. Readers of this book will help determine it. intelligence. San Francisco: Freeman. Mill, J. S. (1873). Autobiography. London: Longmans. Morey, D. F. (1994). The early evolution of the domestic dog. American References Scientist, 82, 336Ð347. National Society for the Study of Education (1928). 27th yearbook: Nature and nurture. Bloomington. IL: Public School Publishing. Brewer, D. J., Clark, T., & Phillips, A. (2001). Dogs in antiquity. Pearson, R. (1991). Race, intelligence and bias in academe. Washing- Warminster, England: Aris & Phillips. ton, DC: Scott-Townsend. Burks, B. S. (1928). The relative influence of nature and nurture upon Pearson, R. (1995). The concept of heredity in the history of Western mental development: A comparative study of foster parent-foster culture: Part One. The Mankind Quarterly, 35, 229Ð266. child resemblance and true parent-true child resemblance. In 27th Pinker, S. (2002). The blank slate: The modern denial of human nature. Yearbook of the National Society for the Study of Education, Part 1, New York: Viking. pp. 219Ð316. Plato (n.d./1901). The Republic (B. Jowett, Trans.). New York: Willey Burt, C. (1961). Intelligence and social mobility. British Journal of Sta- Book Co. tistical Psychology, 14, 3Ð24. Porter, N. (1887). Marginalia Locke-a-na. New Englander and Yale Darwin, C. (1859). On the origin of species by means of natural selec- Review, 11, 33Ð49. tion. London: John Murray. Reynolds, C. R., Chastain, R. L., Kaufman, A. S., & McLean, J. T. Darwin, C. (1871). The descent of man, and selection in relation to sex. (1987). Demographic characteristics and IQ among adults: Anal- London: John Murray. ysis of the WAIS-R standardization sample as a function of the Darwin, C. (1872). The expression of the emotions in man and animals. stratification variables. Journal of School Psychology, 25, 323Ð342. London: John Murray. Rowe, D. C., Vesterdal, W. J., & Rodgers, J. L. (1998). Herrnstein’s Ebbinghaus, H. (1908). Psychology: An elementary textbook (M. F. syllogism: Genetic and shared environmental influences on IQ, edu- Meyer, Trans.). Boston: D. C. Heath. cation, and income. Intelligence, 26, 405Ð423. 1 History of Behavior Genetics 11

Rushton, J. P., & Jensen, A. R. (2005). Thirty years of research on race Tambs, K., Sundet, J. M., Magnus, P., & Berg, K. (1989). Genetic and differences in cognitive ability. Psychology, Public Policy, and Law, environmental contributions to the covariance between occupational 11, 235Ð294. status, educational attainment, and IQ: A study of twins. Behavior Savolainen, P., Zhang, Y., Luo, J., Lundeberg, J., & Leitner, T. (2002). Genetics, 19, 209Ð222. Genetic evidence for an East Asian origin of domestic dogs. Science, Vandenberg, S. G., & DeFries, J. C. (1970). Our hopes for behavior 298, 1610Ð1613. genetics. Behavior Genetics, 1, 1Ð2. Summers, L. H. (2005). Remarks at NBER conference on diversifying Watson, J. B. (1925). Behaviorism. New York: Norton. science & engineering workforce. Retrieved September 18, 2005, Whitney, G. (1995). Twenty-five years of behavior genetics. Mankind from http://www.president.harvard.edu/speeches/2005/nber.html Quarterly, 35, 328Ð342. Part I Quantitative Methods and Models Chapter 2 Biometrical Models in Behavioral Genetics

Michael C. Neale

Introduction to understand the origins of behavioral differences, and with good reason. Many of the most pressing health problems in The main goal of this chapter is to describe the research modern cultures have behavioral components: obesity, car- designs and statistical methods that are in popular use in diovascular disease, cancer, drug abuse and psychopathology behavioral genetics (BG). We begin with a brief overview of are obvious examples. It is also the case that human con- the historical background to BG in general and twin studies flicts, be it a marital dispute, a street fight, or a world war, in particular. Next, we describe some elementary statistics are primarily behavioral. Thus much of human suffering has required for understanding biometrical modeling. Then fol- behavioral origins. One aim of BG is to identify potential lows a statistical model for genetic variation, as articulated by ways to alleviate this distress by correctly identifying both Fisher in his classic 1918 paper, in which additive and dom- genetic and environmental sources of individual differences inance genetic variance terms are defined. The coefficients in behavior and susceptibility to environmental insults. of resemblance between relatives derived from this model Behavioral genetics as a field was perhaps first established are then implemented in structural equation models for the by the exceptional 18th century cousins, Charles Darwin and analysis of data from twins and other relatives. Overall the Francis Galton. The former, in Chapter 8 of On the Ori- intent is to provide a general and extensible infrastructure for gin of Species (Darwin, 1859) discusses instincts in animals the modeling of genetically informative data. as diverse as dogs, birds, insects, and notes individual dif- ferences in behavior within species. In his later work, the Descent of Man (Darwin, 1871), he wrote: Historical Background If no organic being excepting man had possessed any mental power, or if his powers had been of a wholly different nature from those of the lower animals, then we should never have been Behavior genetics is the synthesis of two domains: behavior, able to convince ourselves that our high faculties had been grad- which is defined as the actions or reactions of an object or ually developed. But it can be shown that there is no fundamental difference of this kind. organism, and genetics, which is the science of heredity and variation. The primary focus of contemporary BG is variation It is well known that different breeds of dog have differ- in behavior, while broader psychological constructs such as ent average temperaments. Typically, Labradors are affec- internal mental states and cognition are frequently included. tionate, Border Collies are intelligent and Bull Terriers are Individual differences in this activity are readily observed in aggressive. Even the most ardent critics of behavioral genet- virtually all forms of animal life and may also be seen in ics do not seem to quibble with this or any other behavioral certain plant species, such as Dionaea muscipula (the Venus differences that are observed in either domesticated species Fly Trap). The ability to predict behavior in other organisms, or those in the wild (Mann, 1994). That selection experi- be they of the same or a different species Ð would seem to ments can produce reliable behavioral differences between have substantial survival value. Today, tremendous invest- strains of rats and mice is well established for numerous ment is made by both medical and military agencies in order traits, including mazesolving ability (Tryon, 1941), activity (Defries, Gervais, & Thomas, 1978), brain weight (Fuller & Herman, 1974), and alcohol preference (Li, Lumeng, & M.C. Neale (B) Doolittle, 1993). Selective breeding experiments are essen- Departments of Psychiatry and Human Genetics, Virginia Institute for tially univariate in design; those with high or low scores on Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298-0126, USA the single trait of interest are used to populate the next gen- e-mail: [email protected] eration. However, it is commonly observed that changes in

Y.-K. Kim (ed.), Handbook of Behavior Genetics, 15 DOI 10.1007/978-0-387-76727-7 2, c Springer Science+Business Media, LLC 2009