The Nature of Intelligence: Novartis Foundation Symposium 233. Volume 233 Edited by Gregory R. Bock, Jamie A. Goode and Kate Webb Copyright Novartis Foundation 2000. ISBN: 0-471-49434-8 THE NATURE OF INTELLIGENCE The Novartis Foundation is an international scienti¢c and educational charity (UK Registered Charity No. 313574). Known until September 1997 as the Ciba Foundation, it was established in 1947 by the CIBA company of Basle, which merged with Sandoz in 1996, to form Novartis. The Foundation operates independently in London under English trust law. It was formally opened on 22 June 1949. The Foundation promotes the study and general knowledge of science and in particular encourages international co-operation in scienti¢c research. To this end, it organizes internationally acclaimed meetings (typically eight symposia and allied open meetings and 15^20 discussion meetings) and publishes eight books per year featuring the presented papers and discussions from the symposia. 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Contents SymposiumonThenatureofintelligence,held atthe Novartis Foundation, London, 30 Nov^2 Dec 1999 Editors: Gregory R. Bock (Organizer),Jamie A. Goodeand KateWebb Thissymposiumis based on a proposalmade by Geo¡rey Miller Michael Rutter Introduction 1 David Lubinski Intelligence: success and ¢tness 6 Discussion 27 Arthur R. Jensen The g factor: psychometrics and biology 37 Discussion 47 IanJ. Deary Psychometric intelligence di¡erences and brain function 58 Discussion 73 Britt Anderson The g factor in non-human animals 79 Discussion 90 Randolph M. Nesse Natural selection, mental modules and intelligence 96 Discussion 105 General discussion I 116 Nathan Brody g and the one ^many problem: is one enough? 122 Discussion 129 Douglas K. Detterman General intelligence and the de¢nition of phenotypes 136 Discussion 144 David Houle Is there a g factor for ¢tness? 149 Discussion 159 J. Michael Bailey How can psychological adaptations be heritable? 171 Discussion 180 v vi CONTENTS Andrew Whiten Social complexity and social intelligence 185 Discussion 196 James R. Flynn IQ gains,WISC subtests and £uid g: g theory and the relevance of Spearman’s hypothesis to race 202 Discussion 216 Andrew Pomiankowski Mutation, selection and the heritability of complex traits 228 Discussion 237 Peter McGu⁄n The quantitative and molecular genetics of human intelligence 243 Discussion 255 Geo¡rey Miller Sexual selection for indicators of intelligence 260 Discussion 270 Final general discussion 276 Michael Rutter Closing remarks 281 Index of contributors 288 Subject index 290 Participants B. Anderson Neurology (127), BirminghamVA Medical Center, 700 S 19th Street, Birmingham, AL 35233, USA J. M. Bailey Department of Psychology, Northwestern University, 2029 Sheridan Road, Evanston, IL 60208-2710, USA N. Brody Department of Psychology,Wesleyan University, Middletown, CT 06459, USA I. J. Deary Department of Psychology, University of Edinburgh,7 George Square, Edinburgh EH8 9JZ, UK D. K. Detterman Department of Psychology, CaseWestern Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7123, USA R. Dunbar School of Biological Sciences, Nicholson Building, University of Liverpool, Liverpool L69 3BX, UK J. R. Flynn Department of Political Studies, University of Otago, PO Box 56, Dunedin, New Zealand S. Gangestad Department of Psychology, University of New Mexico, Albuquerque,NM87131,USA S. Harnad Department of Electronics and Computer Science, University of Southampton, High¢eld, Southampton SO171BJ, UK R. Hinde StJohn’s College, Cambridge CB2 1TP, UK D. Houle Department of Biological Science, Florida State University, Tallehassee, FL 32306-1100, USA vii viii PARTICIPANTS N. Humphrey Centre for Philosophy of Natural and Social Science (CPNSS), Tymes Court Building, London School of Economics, Houghton Street, LondonWC2A 2AE, UK A. R. Jensen Graduate School of Education, University of California, Berkeley, CA 94720-1670, USA A. Karmilo¡-Smith Neurocognitive Development Unit, Institute of Child Health, 30 Guilford Street, LondonWC1N1EH, UK D. Lubinski Department of Psychology and Human Development,Vanderbilt University, Nashville,TN 37203, USA N. J. Mackintosh Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK J. Maynard Smith School of Biological Sciences, Biology Building, University of Sussex, Falmer, Brighton BN19QG, UK P. McGu⁄n Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, King’s College London, De Crespigny Park, Denmark Hill, London SE5 8AF, UK G. Miller Centre for Economic Learning and Social Evolution, University College London, Gower Street, LondonWC1E 6BT, UK R. M. Nesse Department of Psychiatry and Institute for Social Research,The University of Michigan, Ann Arbor, MI 48106-1248, USA A. Pomiankowski The Galton Laboratory, Department of Biology, University College London, London NW1 2HE, UK M. Rutter (Chair) Institute of Psychiatry, De Crespigny Park, Denmark Hill, London SE5 8AF, UK T. Suddendorf (Bursar) School of Psychology, University of Queensland, Brisbane, QLD 4072, Australia A.Whiten School of Psychology, University of St Andrews, St Andrews, Fife KY16 9AJ, UK The Nature of Intelligence: Novartis Foundation Symposium 233. Volume 233 Edited by Gregory R. Bock, Jamie A. Goode and Kate Webb Copyright Novartis Foundation 2000. ISBN: 0-471-49434-8 Introduction Michael Rutter Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London SE5 8AF, UK The main rationale put forward for this meeting was that there was an apparent clash between the expectations of evolutionary psychologists and the claims of behaviour geneticists with respect to genetic in£uences on variations in intelligence. Evolutionary psychologists, it was said, would expect that a trait so strongly adaptive as general intelligence would have been intensely shaped by natural selection and that, as a result, intelligence should show only weak genetic e¡ects on individual variations within the population (Tooby & Cosmides 1990). By contrast, behaviour geneticists have argued that empirical research ¢ndings have been consistent in showing a high heritability for intelligence. The supposed quandary was how to explain why the high intelligence that distinguishes us from other species, and which must have been under strong selection, nevertheless still shows large individual di¡erences that are subject to strong genetic in£uences. In trying, over the course of the next few days, to come up with some kind of resolution of this apparent paradox, we will need to consider carefully the assumptions that underlie this proposition. The starting point, I suppose, is the theoretical expectation that traits under strong selection tend to have low heritability and that evolution by natural selection destroys the genetic variation on which it feeds (Dawkins 1999, citing Falconer 1960 and Lewontin 1979). Probably, most of us will