The human ability to form large, coordinated groups is among our most impressive social adaptations. Larger groups facilitate synergistic economies of scale for cooperative breeding, such economic tasks as group hunting, and success in conflict with other groups. In many organisms, genetic relationships provide the structure for sociality to evolve via the process of kin selection, and this is the case, to a certain extent, for humans. But assortment by genetic affiliation is not the only mechanism that can bring people (...) together. Affinity based on symbolically mediated and socially constructed identity, or cultural kinship, structures much of human ultrasociality. This paper examines how genetic kinship and two kinds of cultural kinship—affinal kinship and descent—structure the network of cooperating whale hunters in the village of Lamalera, Indonesia. Social network analyses show that each mechanism of assortment produces characteristic networks of different sizes, each more or less conducive to the task of hunting whales. Assortment via close genetic kin relationships (r = 0.5) produces a smaller, denser network. Assortment via less-close kin relations (r = 0.125) produces a larger but less dense network. Affinal networks are small and diffuse; lineage networks are larger, discrete, and very dense. The roles that genetic and cultural kinship play for structuring human sociality is discussed in the context of these results. (shrink)

Applications of sexual selection theory to humans lead us to expect that because of mammalian sex differences in obligate parental investment there will be gender differences in fitness variances, and males will benefit more than females from multiple mates. Recent theoretical work in behavioral ecology suggests reality is more complex. In this paper, focused on humans, predictions are derived from conventional parental investment theory regarding expected outcomes associated with serial monogamy and are tested with new data from a postreproductive cohort (...) of men and women in a primarily horticultural population in western Tanzania (Pimbwe). Several predictions derived from the view that serial monogamy is a reproductive strategy from which males benefit are not supported. Furthermore, Pimbwe women are the primary beneficiaries of multiple marriages. The implications for applications of sexual selection theory to humans are discussed, in particular the fact that in some populations women lead sexual and reproductive lives that are very different from those derived from a simple Bateman-Trivers model. (shrink)

The incorporation of niche construction theory (NCT) and epigenetics into an extended evolutionary synthesis (EES) increases the explanatory power of evolutionary analyses of human history. NCT allows identification of distinct social inheritance and cultural inheritance and can thereby account for how an existing-but-dynamic social system yields variable influences across individuals and also how these individuals’ microlevel actions can feed back to alter the dynamic heterogeneously across time and space. An analysis of Chinese footbinding, as it was ending during the first (...) half of the twentieth century and China was industrializing, illustrates the evolutionary dynamics of niche construction across inheritance tracks and explains regional heterogeneity as well as the persistence of a cultural belief that was socially inaccurate. Incorporating anthropological and sociological insights into an EES with NCT has the potential to proffer source laws for relationships between individual actions and macro-patterns in beliefs, structures, climate, and demography. (shrink)

La evidencia comparativa reciente sugiere que algunas especies no humanas sienten empatía hacia otros congéneres, la cual es una capacidad necesaria para la presencia y evolución de la moralidad. Por otro lado, la Hipótesis del Cerebro Social plantea relaciones entre la evolución de la neocorteza cerebral en primates y el tamaño de sus grupos sociales. Este artículo vincula estas ideas al señalar que: (i) la empatía y la moralidad son subproductos de la expansión de la neocorteza cerebral, y (ii) la (...) función de tales capacidades es facilitar la cooperación entre individuos, aumentando su cohesión social. Recent comparative evidence suggests that some nonhuman species feel empathy towards fellow group members and empathy is a necessary capacity for the presence and evolution of morality. On the other hand, the Social Brain Hypothesis suggests relationships between the evolution of brain's neocortex in primates and the size of their social groups. This paper links these ideas by suggesting that (i) empathy and morality are by-products of the expansión of brain's neocortex, and that (ii) the function of such capacities is to facilitate cooperation between individuals, increasing their social cohesion. (shrink)