Out of the Armchair


Department of Psychology, University of Edinburgh, UK

Penke et al. (this issue) attempt to explain personality and cognition from theory rather than empirical study. This overstates the constraints on evolution, while underestimating the power of cross-species HapMap data to directly identify our evolutionary history. Independent of armchair-speculation, information benefiting human understanding, health and well-being is flowing from exactly the research the target suggests should not be pursued. Copyright © 2007 John Wiley & Sons, Ltd.

Personality: Does Selection See It?


Psychology Department, Durham University, UK

Selective neutrality offers a parsimonious explanation for personality variation. Bodily variations which do not compromise function (e.g. differences in intestine route) require no special explanation. Variations of the mind are not in principal different from those of the body. A plausible explanation for such neutrality exists which does not require speculative stories about the circumstances of balancing selection. Copyright © 2007 John Wiley & Sons, Ltd.

An Evolutionary Ecologist's View of How to Study the Persistence of Genetic Variation in Personality


Centre for Behaviour and Neurosciences, University of Groningen, The Netherlands

Personality is commonly regarded to involve either ‘correlations among behavioural traits’ or ‘consistent individual differences in behaviour across contexts’. Any evolutionary explanation for the existence of genetic variation in personality must therefore not only address why genetic variation in single behavioural traits is maintained but also why behavioural traits are correlated, and why individuals show limited behavioural plasticity. Copyright © 2007 John Wiley & Sons, Ltd.

Consilience is Needed, and Consilience Needs Bipartisan Expertise


Institute of Psychology, Department of Economics, University of Kassel, Germany

Despite a common overarching home of biology, evolutionary psychology and behaviour genetics have not fostered mutual exchange. The paper combines expertise in evolutionary genetics and personality theory with didactic skill and makes a strong argument for two mechanisms of evolutionary genetics to explain the persistence of genetic variation in intelligence and personality, thus contributing considerably to inter-disciplinary consilience. Copyright © 2007 John Wiley & Sons, Ltd.

Genetic Variance and Strategic Pluralism


Department of Psychology, University of Arizona, Tucson, USA,

Penke et al. (this issue) have written a provocative paper on the evolutionary genetics of personality, ascribing the maintenance of genetic variation in personality to balancing selection and in cognitive abilities to a balance between mutation pressure and directional selection. Some of the theory and evidence presented appear supportive, but both the theoretical predictions and the supporting empirical evidence remain tentative. Copyright © 2007 John Wiley & Sons, Ltd.

Beyond Just-so Stories Towards a Psychology of Situations: Evolutionary Accounts of Individual Differences Require Independent Assessment of Personality and Situational Variables


Department of Psychology, University of California, Riverside, USA

Evolutionary theory is perhaps better used as a brake on theory than as a source of ‘just-so’ stories of the origin of characteristics. The target paper admirably employs evolutionary theory to test competing models of the maintenance of individual differences. Areas needing further development include separating personality from situational variables, rather than confounding them, and developing a psychology of situations. Copyright © 2007 John Wiley & Sons, Ltd.

Life-History Theory and Evolutionary Genetics


Department of Psychology, University of New Mexico, Albuquerque, USA

Penke et al. (this issue) argue that evolutionary genetics offers important insights into the fundamental nature of personality—how people adaptively adjust to their life circumstances in particular ways, as well as failures to adapt. I strongly endorse this enterprise. It is particularly promising, I suggest, when embedded within life history theory (LHT), a broad evolutionary framework to understand selection on organisms. Copyright © 2007 John Wiley & Sons, Ltd.

Behaviour Genetics' Neglected Twin: Gene-Environment Correlation


Department of Psychiatry, University of British Columbia, Vancouver, Canada

The target paper posits that the driving force behind balancing selection is gene-environment interaction (G×E) that describes environmental control of genes. It is argued that G×E is insufficient to maintain genetic variability and that the concept of gene-environment correlation or genetic control of the environment leads to different conclusions regarding mental illness and hierarchical personality models. Copyright © 2007 John Wiley & Sons, Ltd.

Don't Count on Structural Pleiotropy


1Department of Psychology, University of Edinburgh, UK

2Department of Psychology, University of Minnesota—Twin Cities, USA

Penke et al. (this issue) address the evolution of personality, articulating many insightful and provocative ideas. They do not, however, give enough attention to the role of G-E correlation in the processes they outline. Thus they underestimate the difficulty of establishing the existence of structural pleiotropy and overestimate its ability to help us in understanding the development of personality. Copyright © 2007 John Wiley & Sons, Ltd.

Standards of Evidence in the Nascent Field of Evolutionary Behavioural Genetics


Virginia Institute for Psychiatric and Behavioural Genetics, Virginia Commonwealth University, USA

Penke et al. (this issue) argue that the genetic variation underlying cognitive abilities is probably due to evolutionarily recurrent, deleterious mutations at the thousands of loci that could potentially affect cognitive development, whereas the genetic variation underlying personality is probably due to balancing selection. This may well be correct, but I argue that some of the standards of evidence they forward are not well supported by evolutionary genetics theory. It is important at this early stage of evolutionary behavioural genetics to critically debate the standards of evidence that will help us distinguish between alternative hypotheses. Copyright © 2007 John Wiley & Sons, Ltd.

Humans in Evolutionary Transition?


Department of Psychology, Harvard University, USA

One shortcoming in this otherwise excellent paper is a neglect of additional hypotheses as to the high heritability of behavioural traits that may have been exposed to directional selection. I point to some evidence that humans are in the midst of an evolutionary transition that may account for the genetic variation in such traits. Copyright © 2007 John Wiley & Sons, Ltd.

Personality Traits and Adaptive Mechanisms


Department of Psychiatry, University of British Columbia, Vancouver, Canada

The issues addressed in this paper are basic to the foundation of a science of personality. The integration of behavioural genetic and evolutionary psychology perspectives on personality has the potential to contribute to the integrated conceptual foundation that the field needs. The task that the authors seek to explicate—the factors contributing to genetic variability of personality traits—is an important component of this integration although only part of an evolution-informed model of personality. Copyright © 2007 John Wiley & Sons, Ltd.

Personality Theory Evolves: Breeding Genetics and Cognitive Science


Department of Psychology, University of Cincinnati, USA

Penke et al.'s (this issue) paper makes an important contribution to personality theory, with ramifications beyond genetic studies. It may significantly enhance prediction of behavioural expressions of personality traits from a psychobiological standpoint. Some theoretical challenges remain, including the complex nature of both traits and environmental modulators. The evolutionary genetic model may usefully complement the cognitive-adaptive personality theory developed by Matthews. Copyright © 2007 John Wiley & Sons, Ltd.

Do We Know Enough to Infer the Evolutionary Origins of Individual Differences?


Gerontology Research Center, National Institute on Aging, USA

Psychologists do not yet understand the role of non-additive genetic influences on personality traits or the number of quantitative trait loci (QTLs) for individual traits. Traits vary in their desirability in mates and in their assortative mating. Thus, it is premature to conclude that individual differences in all or any personality traits have evolved by balancing selection. Copyright © 2007 John Wiley & Sons, Ltd.

What Do We Really Know About Selection on Personality?


Département des sciences biologiques, Université du Québec, Montréal, Canada

An evolutionary genetic approach to personality in animals and humans necessarily assumes a link between personality traits and fitness. Evolutionary personality psychologists have mainly focused on an a priori conception of this link to build up evolutionary scenarios. Although this approach has added to our understanding of the variance of personality traits, it needs to be accompanied by an empirical examination of the link between these traits and fitness. Several tools developed by evolutionary biologists could therefore be useful in evolutionary personality studies. Copyright © 2007 John Wiley & Sons, Ltd.

Personality: Possible Effects of Inbreeding Depression on Sensation Seeking


Department of Biological Psychology, Vrije Universiteit, Amsterdam, The Netherlands,

Penke et al. (this issue) state that there are no studies of inbreeding depression on personality. In this response to their paper, we look at the effect of parents being born in the same geographical region on personality in themselves and in their offspring. Results show that when parents come from the same region, both they and their offspring score lower on sensation seeking than when parents come from different regions. These results may suggest effects of inbreeding depression on personality. Copyright © 2007 John Wiley & Sons, Ltd.

A Multitude of Environments for a Consilient Darwinian Meta-Theory of Personality: The Environment of Evolutionary Adaptedness, Local Niches, the Ontogenetic Environment and Situational Contexts


Marketing Department, John Molson School of Business, Concordia University, Montreal, Canada

A consilient and complete evolutionary-based theory of personality must explain the adaptive mechanisms that maintain personality variance at four distinct ‘environmental’ levels: (1) the environment of evolutionary adaptedness (EEA); (2) the environment as defined by a given local niche; (3) the ontogenetic environment and (4) the situational environment germane to the person-situation debate in personality theory. Copyright © 2007 John Wiley & Sons, Ltd.

Insights From Behavioural Syndromes for the Evolutionary Genetics of Personality


1Department of Environmental Science and Policy, University of California, Davis, USA

2Department of Integrative Biology, University of Illinois, Urbana, USA

Behavioural ecologists have recently begun emphasising behavioural syndromes, an analogue of personality. This new area offers several insights for the evolutionary genetics of human personality. In particular, it suggests that human personality research could benefit from emphasising: the evolution of reaction norms, correlational selection, indirect genetic effects (IGE), G×E correlations, social situation and partner choice and social networks. Copyright © 2007 John Wiley & Sons, Ltd.

Using Newer Behavioural Genetic Models and Evolutionary Considerations to Elucidate Personality Dynamics


Department of Psychology, University of Minnesota—Twin Cities, USA,

We expand on the theme of transactions between persons and situations, and genes and environments. Newer models for twin data can handle genotype-environment transaction effects explicitly, and such models can be used to better articulate the origins of variation in personality. Copyright © 2007 John Wiley & Sons, Ltd.

Neurogenetic Mechanisms Underlying Cognition and Temperament


Department of Psychology, Johann Wolfgang Goethe University Frankfurt/Main, Germany

This commentary discusses the target paper's sharp distinction between neurogenetic mechanisms underlying cognitive abilities and temperament. Evidence for associations of genetic polymorphisms with both temperament traits and cognitive control functions and for a shared or at least overlapping neuroanatomy and neuromodulation of cognitive control and of temperament traits may imply that we should consider the existence of cognitive reaction norms. Copyright © 2007 John Wiley & Sons, Ltd.

The Relevance of Personality Disorders for an Evolutionary Genetics of Personality


Department of Neurosciences, University of Rome, Italy

The epidemiology of personality disorders confirms the importance of the evolutionary approach to a better understanding of individual differences in personality traits and adds credibility to the evolutionary genetic model. A full appreciation of the potential of the evolutionary genetic framework requires a critical revision of current measures of personality. Copyright © 2007 John Wiley & Sons, Ltd.

The Need for Inter-disciplinary Research in Personality Studies


Department of Animal Population Biology, Netherlands Institute of Ecology, The Netherlands

The target paper demonstrates the value of evolutionary genetics for personality research. Apart from a summing-up of concepts, the authors validate their theory with evidence from studies on both human- and animal personality. In this commentary, I want to show the need for inter-disciplinary research to answer questions on personality in psychology and biology. Copyright © 2007 John Wiley & Sons, Ltd.