The Westermarck effect (sexual inhibition among individuals raised together) is argued to be mediated olfactorily. Various animals, including humans, distinguish among individuals by scent (significantly determined by MHC genotype), and some avoid cosocialized associates on this basis. Possible models of olfactory mechanisms in humans are evaluated. Evidence suggests aversions develop during an early sensitizing period, attach to persons as much as to their scents, and are more powerful among females than among males. Adult to child aversions may develop similarly, but (...) more likely result from stimulus generalization. This hypothesis accords with current evidence and yields testable predictions (e.g., anosmia will prevent inhibition) that, should they be supported, will conclusively ground the Westermarck effect in a biological mechanism. (shrink)

Two predictions concerning the perceived severity of crimes can be derived from evolutionary theory. The first, arising from the theory of inclusive fitness, is that crimes in general should be viewed as more serious to the degree that the victim is genetically related to the perpetrator. The second, arising from the deleterious effects of inbreeding depression, is that heterosexual sexual coercion should be perceived as more serious the closer the genetic relationship of victim and perpetrator, particularly when the victim is (...) a female of fertile age. Two hundred and thirty university students estimated the magnitude of the severity of brief crime descriptions in three separate studies. In the first two, the biological kinship of victim and perpetrator was varied, and in the third, the hypothetical genetic relatedness of the subject and the fictitious victim was varied. All three studies found the linear relationships between biological kinship and perceived crime severity predicted by theory. (shrink)

Some moral realists claim that moral facts are a species of natural fact, amenable to scientific investigation. They argue that these moral facts are needed in the best explanations of certain phenomena and that this is evidence that they are real. In this paper I present part of a biological account of the function of morality. The account allows the identification of a plausible natural kind that could play the explanatory role that a moral kind would play in naturalist realist (...) theories. It is therefore a candidate for being the moral kind. I argue, however, that it will underdetermine the morally good, that is, identifying the kind is not sufficient to identify what is good. Hence this is not a natural moral kind. Its explanatory usefulness, however, means that we do not have to postulate any further (moral) facts to provide moral explanations. Hence there is no reason to believe that there are any natural moral kinds. (shrink)

Evolutionary debunking arguments appeal to selective etiologies of human morality in an attempt to undermine moral realism. But is morality actually the product of evolution by natural selection? Although debunking arguments have attracted considerable attention in recent years, little of it has been devoted to whether the underlying evolutionary assumptions are credible. In this paper, we take a closer look at the evolutionary hypotheses put forward by two leading debunkers, namely Sharon Street and Richard Joyce. We raise a battery of (...) considerations, both empirical and theoretical, that combine to cast doubt on the plausibility of both hypotheses. We also suggest that it is unlikely that there is in the vicinity a plausible alternative hypothesis suitable for the debunker’s cause. (shrink)

At the bottom of all human activities are “values,” the conviction that some things “ought to be” and others not. Science, however, with its immense interest in mere facts seems to lack all understanding of such‘requiredness.’… A science … which would seriously admit nothing but indifferent facts … could not fail to destroy itself.

Thus declares Francis Hutcheson, expressing a view widespread during the Enlightenment, and throughout the history of philosophy. According to this tradition, we are by nature moral, and ourS concern for good and evil is as natural to us as our capacity to feel pleasure and pain. The link between morality and human nature has been a common theme since ancient times, and, with the rise of modern empirical moral psychology, it remains equally popular today. Evolutionary ethicists, ethologists, developmental psychologists, social (...) neuroscientists, and even some cultural anthropologists tend to agree that morality is part of the bioprogram (e.g., Cosmides & Tooby, 1992; de Waal, 1996; Haidt & Joseph, 2004; Hauser, 2006; Ruse, 1991; Sober & Wilson, 1998; Turiel, 2002). Recently, researchers have begun to look for moral modules in the brain, and they have been increasingly tempted to speculate about the moral acquisition device, and innate faculty for norm acquisition akin to celebrated language acquisition device, promulgated by Chomsky (Dwyer, 1999; Mikhail, 2000; Hauser, this volume). All this talk of modules and mechanism may make some shudder, especially if they recall that eugenics emerged out of an effort to find the biological sources of evil. Yet the tendency to postulate an innate moral faculty is almost irresistible. For one thing, it makes us appear nobler as a species, and for another, it offers an explanation of the fact that people in every corner of the globe seem to have moral rules. Moral nativism is, in this respect, an optimistic doctrine—one that makes our great big world seem comfortingly smaller. I want to combat this alluring idea. I do not deny that morality is ecumenical, but I think it is not innate—at least that the current state of evidence is unpersuasive. Morality, like all human capacities, depends on having particular biological predispositions, but none of these, I submit, deserves to be called a moral faculty. Morality is a byproduct—accidental or invented—of faculties that evolved for other purposes.. (shrink)

Biology and the social sciences share an interest in phylogeny. Biologists know that living species are descended from past species, and use the pattern of similarities among living species to reconstruct the history of phylogenetic branching. Social scientists know that the beliefs, values, practices, and artifacts that characterize contemporary societies are descended from past societies, and some social science disciplines, linguistics and cross cultural anthropology for example, have made use of observed similarities to reconstruct cultural histories. Darwin appreciated that his (...) theory of descent with modification had many similarities of pattern and process to the already well developed field of historical linguistics. In many other areas of social science, however, phylogenetic reconstruction has not played a central role. (shrink)