The publication in 1975 of Edward O. Wilson's Sociobiology provoked a great controversy, for in that work Wilson claimed that ethics was rooted in human biology. On the first page of the book, he asserted that our deepest intuitions of right and wrong are guided by the emotional control centers of the brain, which evolved via natural selection to help the human animal exploit opportunities and avoid threats in the natural environment. In 1998, the publication of Wilson's Consilience renewed the (...) controversy, as he continued to argue for explaining ethics through the biology of the moral sentiments.Footnotes* I am grateful to the Earhart Foundation for a research grant that supported the writing of this essay. (shrink)

Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene’s-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using (...) responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive-fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation. (shrink)

An increasing number of scholars argue that moral judgements are adaptations, i.e., that they have been shaped by natural selection. Is this hypothesis true? In this paper I shall not attempt to answer this important question. Rather, I pursue the more modest aim of pointing out three difficulties that anybody who sets out to determine the adaptedness of moral judgments should be aware of (though some so far have not been aware of). First, the hypothesis that moral judgements are adaptations (...) has been advocated in various different specificities and scopes, and on various different levels. Second, the three kinds of evidence that have most often been appealed to by discussants of this hypothesis require additional arguments. And third, there is significant reasonable disagreement about what moral judgements essentially are. (shrink)

Version 3.0 12/02/00. Submitted to R.M. Nesse The Evolution of Subjective Commitment, Russell Sage Foundation. Please do not cite without author’s permission.  by Peter J. Richerson and Robert Boyd. Comments welcome! Word count 14,487.

E.O. Wilson (1975) described humans as one of the four pinnacles of social evolution. The other pinnacles are the colonial invertebrates, the social insects, and the non-human mammals. Wilson separated human sociality from that of the rest of the mammals because, with the exception of the social insect like Naked Mole Rats, only humans have generated societies of a grade of complexity that approaches that of the social insects and colonial invertebrates. In the last few millennia, human societies have even (...) begun to exceed, in numbers of individuals and degree of complexity, the societies of ants, termites, and corals. (shrink)

Is society an organic whole with each of its many components working together like the organs in a body? Like organisms, societies are composed of many parts which seem to work together enhance their survival. Different people fulfill different, necessary role—subsistence, reproduction, coordination, and defense. Regular exchange of matter and energy guarantees that each component has the resources it needs. Norms, laws and customs regulate virtually every aspect of social interaction, who may marry who, how disputes are resolved, and how (...) verbs should be conjugated. Ritual and religion provide comfort to the sick and fearful, maintain a feeling of solidarity and belonging, and serve to preserve and transmit knowledge through time. Even the simplest human societies seem like complex machines designed for growth and survival. (shrink)

Natural experiments wherein preferred marriage partners are co-reared play a central role in testing the Westermarck hypothesis. This paper reviews two such hitherto largely neglected experiments. The case of the Karo Batak is outlined in hopes that other scholars will procure additional information; the case of the Oneida community is examined in detail. Genealogical records reveal that, despite practicing communal child-rearing, marriages did take place within Oneida. However, when records are compared with first-person accounts, it becomes clear that, owing to (...) age- and gender-segregating practices, most endogamously marrying individuals probably did not share a history of extensive propinquity. (shrink)

The reception so far of Kitcher's Vaulting Ambition reminds me of the old saw about the difference between an optimist and a pessimist. Looking at the same glass of water, the former sees it as half full while the latter sees it as half empty. Some have seen Kitcher's book as a vindication of the possibility of an evolutionary science of human behavior; others have seen it as a devastating critique of the most influential efforts to date to construct such (...) a science. As in the joke about the water glass, both assessments have their point. Sociobiology is a research program, not a unified theory. What one can do is test particular hypotheses within this program and see whether they live up to reasonable standards of rigor and evidence. This is what Kitcher does, with great energy and care. (shrink)

The debate about the credentials of sociobiology has persisted because scholars have failed to distinguish the varieties of sociobiology and because too little attention has been paid to the details of the arguments that are supposed to support the provocative claims about human social behavior. I seek to remedy both deficiencies. After analysis of the relationships among different kinds of sociobiology and contemporary evolutionary theory, I attempt to show how some of the studies of the behavior of nonhuman animals meet (...) the methodological standards appropriate to evolutionary research. I contend that the efforts of E. O. Wilson, Richard Alexander, Charles Lumsden, and others to generate conclusions about human nature are flawed, both because they apply evolutionary ideas in an unrigorous fashion and because they use dubious assumptions to connect their evolutionary analyses with their conclusions. This contention rests on analyses of many of the major sociobiological proposals about human social behavior, including: differences in sex roles, racial hostility, homosexuality, conflict between parents and adolescent offspring, incest avoidance, the avunculate, alliances in combat, female infanticide, and gene–culture coevolution.Vaulting Ambitionthus seeks to identify what is good in sociobiology, to expose the errors of premature speculations about human nature, and to prepare the way for serious study of the evolution of human social behavior. (shrink)

Various anthropologists have alleged that cultural constructions of kinship are at odds with Darwinian understandings of the same phenomena. The argument here is that this is not at all the case if attention is paid to the semantic structure of kinship categories, which reveals that the central members of these categories are indeed close procreative kin. Attention is also drawn to supporting research in cognitive psychology.