Behavioral scientists routinely publish broad claims about human psychology and behavior in the world's top journals based on samples drawn entirely from Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. Researchers – often implicitly – assume that either there is little variation across human populations, or that these “standard subjects” are as representative of the species as any other population. Are these assumptions justified? Here, our review of the comparative database from across the behavioral sciences suggests both that there is (...) substantial variability in experimental results across populations and that WEIRD subjects are particularly unusual compared with the rest of the species – frequent outliers. The domains reviewed include visual perception, fairness, cooperation, spatial reasoning, categorization and inferential induction, moral reasoning, reasoning styles, self-concepts and related motivations, and the heritability of IQ. The findings suggest that members of WEIRD societies, including young children, are among the least representative populations one could find for generalizing about humans. Many of these findings involve domains that are associated with fundamental aspects of psychology, motivation, and behavior – hence, there are no obviousa priorigrounds for claiming that a particular behavioral phenomenon is universal based on sampling from a single subpopulation. Overall, these empirical patterns suggests that we need to be less cavalier in addressing questions ofhumannature on the basis of data drawn from this particularly thin, and rather unusual, slice of humanity. We close by proposing ways to structurally re-organize the behavioral sciences to best tackle these challenges. (shrink)

In this essay I examine a well-known articulation of human nature skepticism, a paper by Hull. I then review a recent reply to Hull by Machery, which argues for an account of human nature that he claims is both useful and scientifically robust. I challenge Machery’s account and introduce an alternative account—the “life-history trait cluster” conception of human nature—that I hold is scientifically sound and makes sense of our intuitions about—and desiderata for—human nature.

There is a puzzling tension in contemporary scientific attitudes towards human nature. On the one hand, evolutionary biologists correctly maintain that the traditional essentialist conception of human nature is untenable; and moreover that this is obviously so in the light of quite general and exceedingly well-known evolutionary considerations. On the other hand, talk of human nature abounds in certain regions of the sciences, especially in linguistics, psychology and cognitive science. In this paper I articulate a conception of human nature that (...) a) captures how cognitive and behavioral scientists tend to deploy the notion whilst, b) evading standard evol-utionary objections, and c) allowing human nature – and theories thereof – to fulfill many of their traditional theoretical roles. (shrink)

Abstract The only biologically respectable notion of human nature is an extremely permissive one that names the reliable dispositions of the human species as a whole. This conception offers no ethical guidance in debates over enhancement, and indeed it has the result that alterations to human nature have been commonplace in the history of our species. Aristotelian conceptions of species natures, which are currently fashionable in meta-ethics and applied ethics, have no basis in biological fact. Moreover, because our folk psychology (...) finds this misleading Aristotelian conception highly tempting, we are in fact better off if we refrain from mentioning human nature altogether in debates over enhancement. Content Type Journal Article Category Special Issue Pages 1-16 DOI 10.1007/s13347-012-0063-x Authors Tim Lewens, Department of History and Philosophy of Science, University of Cambridge, Free School Lane, Cambridge, CB2 3RH UK Journal Philosophy & Technology Online ISSN 2210-5441 Print ISSN 2210-5433. (shrink)

Ernst Mayr has argued that Darwinian theory discredited essentialist modes of thought and replaced them with what he has called "population thinking". In this paper, I characterize essentialism as embodying a certain conception of how variation in nature is to be explained, and show how this conception was undermined by evolutionary theory. The Darwinian doctrine of evolutionary gradualism makes it impossible to say exactly where one species ends and another begins; such line-drawing problems are often taken to be the decisive (...) reason for thinking that essentialism is untenable. However, according to the view of essentialism I suggest, this familiar objection is not fatal to essentialism. It is rather the essentialist's use of what I call the natural state model for explaining variation which clashes with evolutionary theory. This model implemented the essentialist's requirement that properties of populations be defined in terms of properties of member organisms. Requiring such constituent definitions is reductionistic in spirit; additionally, evolutionary theory shows that such definitions are not available, and, moreover, that they are not needed to legitimize population-level concepts. Population thinking involves the thesis that population concepts may be legitimized by showing their connections with each other, even when they are not reducible to concepts applying at lower levels of organization. In the paper, I develop these points by describing Aristotle's ideas on the origins of biological variation; they are a classic formulation of the natural state model. I also describe how the development of statistical ideas in the 19th century involved an abandoning of the natural state model. (shrink)

The object of this paper is to show why recent research in the psychology of deductive and probabilistic reasoning does not have.

Philosophers of biology, such as David Hull and Michael Ghiselin, have argued that the notion of human nature is incompatible with modern evolutionary biology and they have recommended rejecting this notion. In this article, I rebut this argument: I show that an important notion of human nature is compatible with modern evolutionary biology.

If species are the things that evolve at least in large part through the action of natural selection, then both genetic and phenotypic variability are essential to biological species. If all species are variable, then Homo sapiens must be variable. Hence, it is very unlikely that the human species as a biological species can be characterized by a set of invariable traits. It might be the case that at this moment in evolutionary history, all human beings happen to possess a (...) particular set of traits, but if so, this will be in large part an evolutionary accident. As a result, anyone who proposes to base anything, including ethics, on human nature is basing it on historical happenstance. (shrink)

There is a growing consensus that the traditional notion of human nature has failed and that human nature needs to be reconceptualized in light of our current scientific knowledge, including the knowledge gained in genetics and evolutionary biology. In “A Plea for Human Nature,” I highlighted this need, and I engaged in this reconceptualization effort, proposing a new notion of human nature, “the nomological notion of human nature” [Machery (Philosophical Psychology 21:321–330, 2008)]; for some more recent work, see Griffiths (Arts: (...) The Journal of the Sydney University Arts Association, 31:30–57, 2009), (2011); Stotz (Phenomenology and the Cognitive Sciences, 9:483–501, 2010); Samuels (Royal Institute of Philosophy Supplement, 70:1–28, 2012). In “Human Nature: The Very Idea,” Tim Lewens discusses the nomological notion of human nature critically. I am grateful for Lewens’s insightful article, and I examine Lewens’s criticisms in this brief response. (shrink)

The Shape of Thought: How Mental Adaptations Evolve presents a road map for an evolutionary psychology of the twenty-first century. It brings together theory from biology and cognitive science to show how the brain can be composed of specialized adaptations, and yet also an organ of plasticity. Although mental adaptations have typically been seen as monolithic, hard-wired components frozen in the evolutionary past, The Shape of Thought presents a new view of mental adaptations as diverse and variable, with distinct functions (...) and evolutionary histories that shape how they develop, what information they use, and what they do with that information. The book describes how advances in evolutionary developmental biology can be applied to the brain by focusing on the design of the developmental systems that build it. Crucially, developmental systems can be plastic, designed by the process of natural selection to build adaptive phenotypes using the rich information available in our social and physical environments. This approach bridges the long-standing divide between "nativist" approaches to development, based on innateness, and "empiricist" approaches, based on learning. It shows how a view of humans as a flexible, culturally-dependent species is compatible with a complexly specialized brain, and how the nature of our flexibility can be better understood by confronting the evolved design of the organ on which that flexibility depends. (shrink)

The western consensus is that obese women are considered attractive by Afro-Americans and by many societies from nonwestern developing countries. This belief rests mainly on results of nonstandardized surveys dealing only with body weight and size, ignoring body fat distribution. The anatomical distribution of female body fat as measured by the ratio of waist to hip circumference (WHR) is related to reproductive age, fertility, and risk for various major diseases and thus might play a role in judgment of attractiveness. Previous (...) research (Singh 1993a, 1993b) has shown that in the United States Caucasian men and women judge female figures with feminine WHRs as attractive and healthy. To investigate whether young Indonesian and Afro-American men and women rate such figures similarly, female figures representing three body sizes (underweight, normal weight, and overweight) and four WHRs (two feminine and two masculine) were used. Results show that neither Indonesian nor Afro-American subjects judge overweight figures as attractive and healthy regardless of the size of WHR. They judged normal weight figures with feminine WHRs as most attractive, healthy, and youthful. The consensus on women’s attractiveness among Indonesian, Afro-American, and U.S. Caucasian male and female subjects suggests that various cultural groups have similar criteria for judging the ideal woman’s shape. (shrink)