- Email: [email protected]
Nibbling on nature and nurture
Update
290
TRENDS in Ecology and Evolution
example, has three male and two female ‘genders’, when really what is meant is alternative mating tactics), that sexual selection theory is only about ‘good genes’. However, I remain to be convinced that the alternative on offer here (what Roughgarden refers to as ‘social selection’) is really all that different from what most of us already do in behavioural ecology (well, at least those of us whose lives are not entirely consumed by the study of sexual selection, of course). It seemed to me that this section of Evolution’s Rainbow constantly fell foul of the naturalistic fallacy (claiming that what is must be good). I suspect that the underlying problem is the perennial danger of relating science to oneself. This is a surprisingly common problem, even
Vol.19 No.6 June 2004
among evolutionary biologists – especially the moment that human behavioural ecology is mentioned. In research, there is only one rule to follow, and we must follow it assiduously: never ever relate the topics of your research to your own behaviour or to that of those you love. For one thing, the fact that you or your children do not do something can never disprove what is necessarily a statistical rule. More importantly, though, it is almost impossible to retain a sense of dispassionate objectivity when you see yourself as an object of your own research. 0169-5347/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2004.03.023
Nibbling on nature and nurture On Our Minds: How Evolutionary Psychology is Reshaping the Nature-Versus-Nurture Debate by Eric M. Gander. John Hopkins University Press, 2004. US$45.00 hbk (293 pages) ISBN 0 8018 7387 8
Robert Kurzban 3720 Walnut St., University of Pennsylvania, Philadelphia, PA 19104, USA
The spicy appetizer in On Our Minds is the turbulent entry of biological and evolutionary theory into the social sciences, from early work in behavior genetics, to the operatic battles that took place among E.O. Wilson, Richard Lewontin, and Stephen Jay Gould subsequent to the publication of Sociobiology in 1975. The main course consists largely of a description of the delightful combination of evolutionary theory and cognitive psychology. For dessert, we are given a taste of all its political implications. The work is, however, unsatisfying, although in a way that is deliciously ironic. On Our Minds suffers from a shortcoming that illustrates the strength of the evolutionary approach to psychology: the power of functionalspecificity versus the weakness of domain-generality. By serving each topic covered On Our Minds in small helpings, Gander leaves his reader unsatisfied with each, and, unlike a finely crafted sauce, the whole is rather less than the sum of its parts. By trying to accommodate varied tastes for history, science and politics all at once, Gander fulfills none of them. The irony is that this mirrors the emphasis that evolutionary psychological approaches place on the importance of domain specificity in cognition: information-processing mechanisms designed to serve narrow functions are more powerful at generating solutions than are mechanisms with more general functions [1]. Information-processing systems, similar to books of this sort, improve as their focus narrows. This is not to say that there is nothing to like. Gander has a light, fluid style, and the work is tastefully executed. For those who have little background in the debates that Corresponding author: Robert Kurzban ([email protected]). www.sciencedirect.com
have raged in the social sciences over the last hundred years or so, this book does provide a gentle introduction to some of these issues. Having said that, there is perhaps one aspect of On Our Minds that readers might find somewhat unpalatable. After discussing the correct way to think about heritability, with many cautions and caveats (e.g. p. 79), Gander claims that it might be difficult to change a child’s temperament ‘because temperament…is highly heritable’ (p. 190, emphasis added). As any number of those trying to untangle the nature– nurture debate have pointed out, high heritability in a trait does not by itself tell you that it is going to be difficult to change the phenotype [2].The usual example is phenylketonuria (PKU), a condition in which phenylalanine is not properly broken down, which can lead ultimately to mental retardation. In many populations, the trait is highly heritable. To change the phenotype, one need only modify one’s diet, avoiding foods containing phenylalanine [3]. A second irony – considerably less delicious than the first – is that authors of volumes that try to untangle the nature– nurture debate continue to get tripped up in this regard [4]. In any case, by attempting to serve up so many ingredients of evolutionary psychology – including its history, scientific significance, and political implications – Gander can treat each only superficially, without the depth that each aspect deserves. This precludes the fine feasts embodied in the works of some of the best science writers of our day who have covered these issues at length – and depth – in an array of fine books. Segerstra˚lle, for example, provides a wonderful, panoramic view of the history of the debate, with an emphasis on the clash of the Titans alluded to above [5]. Dawkins’ work on the theoretical underpinning of evolutionary biology remains a classic [6]. Tooby and Cosmides’ chapter provides the foundational work that pulls together cognition and evolution [1]. For a lucid
Update
TRENDS in Ecology and Evolution
account of how applying the theory of natural selection to the human mind (r)evolutionized cognitive science, see Pinker [7], who can also be tapped for his insights into continuing political aspects of the debate [8]. And of course, evolutionary accounts of particular content areas (e.g. mating [9]) are appearing with increasing frequency. On Our Minds might be sufficient for those who like to snack at the buffet or sample the offerings of the smorgasbord. However, for those who like to sit down at a fine repast, savoring the intricacies of ideas and events as carefully as the dynamics of a complex dish, readers should have a gander, but ultimately look elsewhere to satisfy their cravings. References 1 Tooby, J. and Cosmides, L. (1992) The psychological foundations of
2 3 4 5 6 7 8
Vol.19 No.6 June 2004
291
culture. In The Adapted Mind (Barkow, L. et al., eds), pp. 19 – 136, Oxford University Press Konnor, M. (2002) The Tangled Wing: Biological Constraints on the Human Spirit, 2nd edn, Freeman Kurzban, R. (2003) Review of ‘The Tangled Wing: Biological Constraints on the Human Spirit’ (2nd edn). Evol. Hum. Behav. 24, 148– 152 Segerstra˚lle, U. (2001) Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond, Oxford University Press Dawkins, R. (1976) The Selfish Gene, Oxford University Press Pinker, S. (1997) How the Mind Works, Norton Pinker, S. (2002) The Blank Slate: The Modern Denial of Human Nature, Viking Buss, D.M. (1994) The Evolution of Desire: Strategies of Human Mating, Basic Books
0169-5347/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2004.03.032
Intertwined fates Tangled Trees. Phylogeny, Cospeciation, and Coevolution edited by Roderic D.M. Page. The University of Chicago Press, 2003. US$28.00 pbk (350 pages) ISBN 0 226 64467 7
David L. Wagner Ecology & Evolutionary Biology, U-Box 43, University of Connecticut, Storrs, CT 06269-3043, USA
Tangled Trees is a collection of 13 very readable chapters about testing for cospeciation across an array of host – parasite systems. The theory and methods applied to the examples have applications outside the cospeciation systems that are the focus of the book and, in particular, have analogies in the matching of gene trees to species trees and biogeographic studies that seek to find correspondence between organismal phylogenies and area cladograms (and associated vicariant events) [1]. Page introduces the book with a concise overview of issues, definitions and methods that serve as primer to the science of cospeciation. The remainder of his chapter points out key contributions from each of the chapters and includes a brief glossary. Of broadest significance are the four initial chapters that examine methodological and theoretical issues involved in the analytical evaluation of cospeciation. Ronquist thoroughly lays out a new event-based parsimony approach that allows host shifts; more importantly, his method does not assume maximum cospeciation as does Page’s TreeMap. Charleston and Perkins offer a gentle introduction to their ‘Jungle’ approach, which not only considers all possible ways for reconciling disagreement between two phylogenies, but also allows differential weighting of various reconciliation scenarios. Although the Jungle method might boast clear advantages over TreeMap, its implementation is currently limited to just 12 host– parasite pairs. The Bayesian approach introduced by Huelsenbeck et al. has appeal in that it compares the likelihood of cospeciation events using the character data for Corresponding author: David L. Wagner ([email protected]). www.sciencedirect.com
both host and parasite, in essence, considering different trees in proportion to their posterior probabilities. By contrast, TreeMap, TreeFitter (Ronquist’s parsimony method) and the Jungle method all compare tree topologies (and therefore assume that the topologies for both host and parasite are correct). Although the model presented by Huelsenbeck et al. is simplified – for example, all incongruence comes about by host switches – it is just a matter of time before more complex Bayesian models are developed. This section of the volume would have benefited from a chapter by Page about his TreeMap Program (the industry standard: http://taxonomy.zoology.gla.ac.uk/%7emac/ treemap/index.html). Page has wrestled with the analytical problems of measuring cospeciation for more than a decade – his insight to the limitations of existing methods and future directions would have been helpful. To measure cospeciation, one merely has to evaluate the degree of congruence between two trees. Sounds simple, but, in most biological systems, tree fitting is a messy business. There might be more ways to reconcile differences between two trees than Michoacan has monarchs. Even with modest topological differences, there exist many combinations of host switches, sorting events, extinctions, duplications, and so on that could be postulated to reconcile two trees. Which scenario is correct? Reconciliation becomes even more ad hoc when assigning weights or probabilities to each such postulated event. A host switch to a sister taxon certainly seems more likely than is a jump to a taxonomically distant clade. Jungles indeed. Given such methodological complexities, it was helpful having authors in several of the chapters proposing and advocating alternative methods – one soon learns the difficulties that are associated with rigorously trying to measure cospeciation.
290
TRENDS in Ecology and Evolution
example, has three male and two female ‘genders’, when really what is meant is alternative mating tactics), that sexual selection theory is only about ‘good genes’. However, I remain to be convinced that the alternative on offer here (what Roughgarden refers to as ‘social selection’) is really all that different from what most of us already do in behavioural ecology (well, at least those of us whose lives are not entirely consumed by the study of sexual selection, of course). It seemed to me that this section of Evolution’s Rainbow constantly fell foul of the naturalistic fallacy (claiming that what is must be good). I suspect that the underlying problem is the perennial danger of relating science to oneself. This is a surprisingly common problem, even
Vol.19 No.6 June 2004
among evolutionary biologists – especially the moment that human behavioural ecology is mentioned. In research, there is only one rule to follow, and we must follow it assiduously: never ever relate the topics of your research to your own behaviour or to that of those you love. For one thing, the fact that you or your children do not do something can never disprove what is necessarily a statistical rule. More importantly, though, it is almost impossible to retain a sense of dispassionate objectivity when you see yourself as an object of your own research. 0169-5347/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2004.03.023
Nibbling on nature and nurture On Our Minds: How Evolutionary Psychology is Reshaping the Nature-Versus-Nurture Debate by Eric M. Gander. John Hopkins University Press, 2004. US$45.00 hbk (293 pages) ISBN 0 8018 7387 8
Robert Kurzban 3720 Walnut St., University of Pennsylvania, Philadelphia, PA 19104, USA
The spicy appetizer in On Our Minds is the turbulent entry of biological and evolutionary theory into the social sciences, from early work in behavior genetics, to the operatic battles that took place among E.O. Wilson, Richard Lewontin, and Stephen Jay Gould subsequent to the publication of Sociobiology in 1975. The main course consists largely of a description of the delightful combination of evolutionary theory and cognitive psychology. For dessert, we are given a taste of all its political implications. The work is, however, unsatisfying, although in a way that is deliciously ironic. On Our Minds suffers from a shortcoming that illustrates the strength of the evolutionary approach to psychology: the power of functionalspecificity versus the weakness of domain-generality. By serving each topic covered On Our Minds in small helpings, Gander leaves his reader unsatisfied with each, and, unlike a finely crafted sauce, the whole is rather less than the sum of its parts. By trying to accommodate varied tastes for history, science and politics all at once, Gander fulfills none of them. The irony is that this mirrors the emphasis that evolutionary psychological approaches place on the importance of domain specificity in cognition: information-processing mechanisms designed to serve narrow functions are more powerful at generating solutions than are mechanisms with more general functions [1]. Information-processing systems, similar to books of this sort, improve as their focus narrows. This is not to say that there is nothing to like. Gander has a light, fluid style, and the work is tastefully executed. For those who have little background in the debates that Corresponding author: Robert Kurzban ([email protected]). www.sciencedirect.com
have raged in the social sciences over the last hundred years or so, this book does provide a gentle introduction to some of these issues. Having said that, there is perhaps one aspect of On Our Minds that readers might find somewhat unpalatable. After discussing the correct way to think about heritability, with many cautions and caveats (e.g. p. 79), Gander claims that it might be difficult to change a child’s temperament ‘because temperament…is highly heritable’ (p. 190, emphasis added). As any number of those trying to untangle the nature– nurture debate have pointed out, high heritability in a trait does not by itself tell you that it is going to be difficult to change the phenotype [2].The usual example is phenylketonuria (PKU), a condition in which phenylalanine is not properly broken down, which can lead ultimately to mental retardation. In many populations, the trait is highly heritable. To change the phenotype, one need only modify one’s diet, avoiding foods containing phenylalanine [3]. A second irony – considerably less delicious than the first – is that authors of volumes that try to untangle the nature– nurture debate continue to get tripped up in this regard [4]. In any case, by attempting to serve up so many ingredients of evolutionary psychology – including its history, scientific significance, and political implications – Gander can treat each only superficially, without the depth that each aspect deserves. This precludes the fine feasts embodied in the works of some of the best science writers of our day who have covered these issues at length – and depth – in an array of fine books. Segerstra˚lle, for example, provides a wonderful, panoramic view of the history of the debate, with an emphasis on the clash of the Titans alluded to above [5]. Dawkins’ work on the theoretical underpinning of evolutionary biology remains a classic [6]. Tooby and Cosmides’ chapter provides the foundational work that pulls together cognition and evolution [1]. For a lucid
Update
TRENDS in Ecology and Evolution
account of how applying the theory of natural selection to the human mind (r)evolutionized cognitive science, see Pinker [7], who can also be tapped for his insights into continuing political aspects of the debate [8]. And of course, evolutionary accounts of particular content areas (e.g. mating [9]) are appearing with increasing frequency. On Our Minds might be sufficient for those who like to snack at the buffet or sample the offerings of the smorgasbord. However, for those who like to sit down at a fine repast, savoring the intricacies of ideas and events as carefully as the dynamics of a complex dish, readers should have a gander, but ultimately look elsewhere to satisfy their cravings. References 1 Tooby, J. and Cosmides, L. (1992) The psychological foundations of
2 3 4 5 6 7 8
Vol.19 No.6 June 2004
291
culture. In The Adapted Mind (Barkow, L. et al., eds), pp. 19 – 136, Oxford University Press Konnor, M. (2002) The Tangled Wing: Biological Constraints on the Human Spirit, 2nd edn, Freeman Kurzban, R. (2003) Review of ‘The Tangled Wing: Biological Constraints on the Human Spirit’ (2nd edn). Evol. Hum. Behav. 24, 148– 152 Segerstra˚lle, U. (2001) Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond, Oxford University Press Dawkins, R. (1976) The Selfish Gene, Oxford University Press Pinker, S. (1997) How the Mind Works, Norton Pinker, S. (2002) The Blank Slate: The Modern Denial of Human Nature, Viking Buss, D.M. (1994) The Evolution of Desire: Strategies of Human Mating, Basic Books
0169-5347/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2004.03.032
Intertwined fates Tangled Trees. Phylogeny, Cospeciation, and Coevolution edited by Roderic D.M. Page. The University of Chicago Press, 2003. US$28.00 pbk (350 pages) ISBN 0 226 64467 7
David L. Wagner Ecology & Evolutionary Biology, U-Box 43, University of Connecticut, Storrs, CT 06269-3043, USA
Tangled Trees is a collection of 13 very readable chapters about testing for cospeciation across an array of host – parasite systems. The theory and methods applied to the examples have applications outside the cospeciation systems that are the focus of the book and, in particular, have analogies in the matching of gene trees to species trees and biogeographic studies that seek to find correspondence between organismal phylogenies and area cladograms (and associated vicariant events) [1]. Page introduces the book with a concise overview of issues, definitions and methods that serve as primer to the science of cospeciation. The remainder of his chapter points out key contributions from each of the chapters and includes a brief glossary. Of broadest significance are the four initial chapters that examine methodological and theoretical issues involved in the analytical evaluation of cospeciation. Ronquist thoroughly lays out a new event-based parsimony approach that allows host shifts; more importantly, his method does not assume maximum cospeciation as does Page’s TreeMap. Charleston and Perkins offer a gentle introduction to their ‘Jungle’ approach, which not only considers all possible ways for reconciling disagreement between two phylogenies, but also allows differential weighting of various reconciliation scenarios. Although the Jungle method might boast clear advantages over TreeMap, its implementation is currently limited to just 12 host– parasite pairs. The Bayesian approach introduced by Huelsenbeck et al. has appeal in that it compares the likelihood of cospeciation events using the character data for Corresponding author: David L. Wagner ([email protected]). www.sciencedirect.com
both host and parasite, in essence, considering different trees in proportion to their posterior probabilities. By contrast, TreeMap, TreeFitter (Ronquist’s parsimony method) and the Jungle method all compare tree topologies (and therefore assume that the topologies for both host and parasite are correct). Although the model presented by Huelsenbeck et al. is simplified – for example, all incongruence comes about by host switches – it is just a matter of time before more complex Bayesian models are developed. This section of the volume would have benefited from a chapter by Page about his TreeMap Program (the industry standard: http://taxonomy.zoology.gla.ac.uk/%7emac/ treemap/index.html). Page has wrestled with the analytical problems of measuring cospeciation for more than a decade – his insight to the limitations of existing methods and future directions would have been helpful. To measure cospeciation, one merely has to evaluate the degree of congruence between two trees. Sounds simple, but, in most biological systems, tree fitting is a messy business. There might be more ways to reconcile differences between two trees than Michoacan has monarchs. Even with modest topological differences, there exist many combinations of host switches, sorting events, extinctions, duplications, and so on that could be postulated to reconcile two trees. Which scenario is correct? Reconciliation becomes even more ad hoc when assigning weights or probabilities to each such postulated event. A host switch to a sister taxon certainly seems more likely than is a jump to a taxonomically distant clade. Jungles indeed. Given such methodological complexities, it was helpful having authors in several of the chapters proposing and advocating alternative methods – one soon learns the difficulties that are associated with rigorously trying to measure cospeciation.