LJEAVES II J EYSENCIZ 1\J G Nli\RTIN

Transcription

1 ';1 '\ 0 G 1 D\ 'C-l. ptrt':l'in'\lf"l ilea' I a p' nro~j'l'cn;l, J..:li.1,,,,,,,lUl.1 lull. 11.,.' I.' I. :u l, : Czt. \ ;i.:r! 11: LJEAVES II J EYSENCIZ 1\J G Nli\RTIN

2 ACADEMIC PRESS LIMITED Oval Road London NW1 7DX United States Edition published by ACADEMIC PRESS INC. San Diego, CA Copyright 1989 by ACADEMIC PRESS LIMITED All Rights Reserued No part of this book may be reproduced in any form by photostat, microfilm, or by any other means, without written permission from the publishers British Library Cataloguing in Publication Data Eaves, L.J. Genes, culture and personality: an empirical approach. 1. Man. Behaviour. Genetic factors I. Title II. Eysenck, H.J. (Hans Jiirgen), III. Martin, N.G ISBN Typeset by Colset Pte Ltd, Singapore Printed in Great Britain by T.J. Press (Padstow) Ltd, Padstow, Cornwall

3 Authors L.J. Eaves Department of Human Genetics, Medical College of Virginia, Box 33, Richmond, Virginia 23298, USA H.J. Eysenck Department of Psychology, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London SE5 8AP, UK N.G. Martin Queensland: Institute of Medical Research, Brisbane, Queensland 4006, Australia R. Jardine Alcohol and Drug Service, Australian Capital Territory Health Authority, Box 825, Canberra, ACT 2601, Australia A. C. Heath Department of Human Genetics, Medical College of Virginia, Box 33, Richmond, Virginia 23298, USA. L. Feingold Department of Experimental Psychology, University of Oxford, Oxford OXI 2JD, UK P.A. Young Department of Genetics, University of Birmingham, PO Box 363, Birmingham B15 2TT, UK K. S. Kendler Department of Psychiatry, Medical College of Virginia, Box 710, Richmond, Virginia 23298, USA

4 Genes, Culture and Personality An Empirical Approach L.J. EAVES Department of Human Genetics Medical College of Virginia Richmond, Virginia, USA H.J. EYSENCK Department of Psychology Institute of Psychiatry London, UK N.G.MARTIN Queensland Institute of Medical Research Queensland, Australia With contributions by R. JARDINE, A.c. HEATH, L. FEINGOLD, P.A. YOUNG, K.S. KENDLER ACADEMIC PRESS Harcourt Brace Jovanovich, Publishers London San Diego New York Berkeley Boston Sydney Tokyo Toronto

5 Contents Preface... vii 1 Another Book on Heritability? Personality and social attitudes Away from the "herita~ty hang-up" Presentation of original data Quantitative modeling and hypothesis testing Sustained study of selected measures Dimensions of Personality Theories of personality... "' The description of personality Testing the model for personality Consistency across measurements Cross-cultural consistency Animal models Developmental consistency Relationship to psychiatric disorder and social behavior Criticisms of the model Criticism of trait theories Nomothetic vs. idiographic methods Inability to explain social behavior Causal aspects of the theory Heuristic value The Classical Approach: Early Twin Studies of Personality History of the twin method Hereditary genius The history of twins

6 xii Contents 3.2 Analyzing twin.data: The classical approach Analysis of variance Genetic and environmental components within families The intraclass correlation and twin similarity The shared environment in the classical approach Criticism of the twin method Additional types of twins? Are twins typical? Correlations in the environments of twins Twin studies of personality before Power and sample size Early twin studies: a "meta-analysis" Summary 41 4 Introduction to Model Fitting What's wrong with the old way Model building Genotype and phenotype Genotype x environment interaction Genotype-environment covariance: the genetic environment The number of genes Gene action and interaction The forgotten environment Model fitting..., Criteria for a "good" model Rationale of model-fitting methods Weighted least squares applied to twin mean squares Fitting a simple non-linear model to correlations Summary Adult Twin Studies of the Major Personality Dimensions The London data Ascertainment... ; Zygosity determination Transformation of the raw scores Age correction Correction for sex differences Data summary Fitting models without sex limitation Method Results Psychoticism... 92

7 Contents xiii Extraversion Neuroticism The Lie scale Models incorporating sex-limited effects Allowing for sex limitation Conclusions from the adult London twin data The US study The Swedish study... ' The Australian study Psychoticism Extraversion Neuroticism The Lie scale Summary and discussion Further Tests of the Model: Studies of Adoptees and Extended Families Assortative mating for the dimensions of personality Adoptions and extended kinships: the London study Source of data The correlations between relatives Inclusion of cultural inheritance and assortative mating Minimization subject to constraints Results of correlational analysis... : Model fitting to unreduced data by maximum-likelihood Results of maximum-likelihood analysis The extended kinships of twins Separated twins Other adoption studies of extraversion and neuroticism Summary... ; Personality Development and Change: A Genetic Perspective Analysis ofp,e,n and Lin juvenile twins Psychoticism Extraversion Neuroticism The Lie scale The causes of developmental stability and change The model... '.' Data summary Method for model fitting Results for the genotype-environment model Neuroticism

8 xiv Contents Extraversion Psychoticism The Lie scale Developmental changes in gene expression in adults Age trends in intrapair twin differences Extended kinships: a developmental model Stability and change in personality The Genetic Analysis of Individual EPQ Items The data... '.' Models Estimation..." Example... : Results Psychoticism Extraversion Neuroticism The Lie scale...' Relationships between items and factors Discussion and summary The Specificity of Gene Effects: Implications for the Interaction of Persons and Situations Personality traits and persons x situations mteraction Thedata Analysis of variance Genetic analysis Do genes affect short-term personality change? Discussion Genetic and Environmental Covariance Between Traits Genetic and environmental covariance: a bivariate study A bivariate modelfor genetic and environmental effects Summarizing multivariate twin data A bivariate example: the nature of extraversion Data and data summary Model fitting to component scores The causes of correlation between the scales The components ofimpulsiveness Models for more than two variables The measurements and sample Data summary

9 Contents xv The model Statistical method for testing the model Results Discussion The covariance structure of neuroticism Data summary Univariate analysis Multivariate analysis Conclusion Normal Personality and Symptoms of Psychiatric Disorder : A Genetic Relationship? The threshold model for individual symptoms Testing genetic models for liability with multiple items Thepsychometricmodel The genetic model Application to,twin data on symptoms of depression Numerical method Results and discussion The relationship between personality and symptoms Correlation between individual symptoms: a genotypeenvironmental model Summary Social Attitudes: A Model of Cultural Inheritance? Analysis of attitude items from the London study Preliminary statistics Twin correlations for the items Item analysis using the threshold model Conservatism items in the Australian sample Questionnaire and preliminary statistics Fitting the threshold model Factor loadings and the shared environment Summary and conclusions..., Conservatism-Radicalism: The Structure of Social Attitudes Twin Studies of Social-Attitude Dimensions Twin studies of conservatism Conservatism in the Australian twin sample The causes of longitudinal consistency in conservatism

10 xvi Contents 14.4 Analysis of primary social-attitude factors Summary Attitudes: Cultural Inheritance or Assortative Mating? A joint analysis of spousal resemblance for personality and attitudes The structure of spousal resemblance in attitudes Resolving assortative mating and cultural inheritance Other data Summary Testing Assumptions About Mate Selection Alternative models for mate selection Assortative mating for environmental determinants... ' Unreliable environmental transmission Reliable environmental transmission A study of twins imd their spouses The data..., A model Results of model fitting Summary Genes, Culture and Behavior... ; Genetic effects on the major dimensions The environment Assortative mating...,..., Developmental change..., Multiple variables Personality and psychiatric symptoms..., Wherenext Theory Data Conclusion Appendices A. 6ample SAS program for iterative weighted least squares analysis of twin mean squares B. The Eysenck Personality Questionnaire (EPQ) C. The Junior Eysenck Personality Questionnaire GEPQ) D. The Public Opinion Inventory (POI)...'

11 Contents xvii E. Item means by Twin Group for the POI items F. Item variances by Twin Group for the POIitems References Subject Index