Partner selection, coordination games, and group selection.

The process of partner selection reflects ethnographic realities where cooperative rewards obtain that would otherwise be lost to loners. Baumard et al. neglect frequency-dependent processes exemplified by games of coordination. Such games can produce multiple equilibria that may or may not include fair outcomes. Additional, group-selection processes are required to produce the outcomes predicted by the models.

A Naturalistic Study of Norm Conformity, Punishment, and the Veneration of the Dead at Texas A&M University, USA.

Culturally inherited institutional norms structure much of human social life. Successfully replicating institutions train their current members to behave in the generally adaptive ways that served past members. Ancestor veneration is a well-known manifestation of this phenomenon whereby deference is conferred to prestigious past members who are used as cultural models. Such norms of respect may be maintained by punishment based on evidence from theory and laboratory experiments, but there is little observational evidence to show that punishment is commonly used. To test for punishment as a mechanism that maintains these norms, we examine a norm of ancestor veneration in a natural field experiment at the Memorial Student Center (MSC) at Texas A&M University. The MSC is a memorial to university war dead, and the expectation is that all who enter the building remove their hats out of respect. Observations reveal that hat removal is significantly more common at the MSC than at two control locations. Survey data indicate that most, but not all, subjects understand the norm to be veneration of the dead, and most expect others to follow the norm. Many report a strong negative emotional response when asked to imagine the norm being violated. Sixty-two percent report they would definitely or probably ask the noncompliant to uncover. Focal follow data show that punishment is relatively rare, however, with the majority of behatted subjects going unreproached as they pass through the building. Both survey and observational data indicate there is a motivated minority that enthusiastically enforces the norm.

The life history of human foraging: Cross-cultural and individual variation.

Human adaptation depends on the integration of slow life history, complex production skills, and extensive sociality. Refining and testing models of the evolution of human life history and cultural learning benefit from increasingly accurate measurement of knowledge, skills, and rates of production with age. We pursue this goal by inferring hunters' increases and declines of skill from approximately 23,000 hunting records generated by more than 1800 individuals at 40 locations. The data reveal an average age of peak productivity between 30 and 35 years of age, although high skill is maintained throughout much of adulthood. In addition, there is substantial variation both among individuals and sites. Within study sites, variation among individuals depends more on heterogeneity in rates of decline than in rates of increase. This analysis sharpens questions about the coevolution of human life history and cultural adaptation.

Using a partial sum method and GPS tracking data to identify area restricted search by artisanal fishers at moored fish aggregating devices in the Commonwealth of Dominica.

Foragers must often travel from a central place to exploit aggregations of prey. These patches can be identified behaviorally when a forager shifts from travel to area restricted search, identified by a decrease in speed and an increase in sinuosity of movement. Faster, more directed movement is associated with travel. Differentiating foraging behavior at patches from travel to patches is important for a variety of research questions and has now been made easier by the advent of small, GPS devices that can track forager movement with high resolution. In the summer and fall of 2012, movement data were collected from GPS devices placed on foraging trips originating in the artisanal fishing village of Desa Ikan (pseudonym), on the east coast of the Caribbean island nation of the Commonwealth Dominica. Moored FADs are human-made structures anchored to the ocean floor with fish attraction material on or near the surface designed to effectively create a resource patch. The ultimate goal of the research is to understand how property rights are emerging after the introduction of fish aggregating device (FAD) technology at the site in 1999. This paper reports on research to identify area-restricted search foraging behavior at FAD patches. For 22 foraging trips simultaneous behavioral observations were made to ground-truth the GPS movement data. Using a cumulative sum method, area restricted search was identified as negative deviations from the mean travel speed and the method was able to correctly identify FAD patches in every case.

Kinship, lineage, and an evolutionary perspective on cooperative hunting groups in Indonesia.

Work was conducted among traditional, subsistence whale hunters in Lamalera, Indonesia, in order to test if strict biological kinship or lineage membership is more important for explaining the organization of cooperative hunting parties ranging in size from 8 to 14 men. Crew identifications were collected for all 853 hunts that occurred between May 3 and August 5, 1999. Lineage identity and genetic relatedness were determined for a sample of 189 hunters. Results of matrix regression show that genetic kinship explains little of the hunters' affiliations independent of lineage identity. Crew members are much more closely related to each other than expected by chance, but this is due to the correlation between lineage membership and genetic kinship. Lineage members are much more likely to affiliate in crews, but kin with r<0.5 are just as likely not to affiliate. The results are discussed vis-à-vis the evolution of cooperation and group identity.

Genetic and cultural kinship among the Lamaleran whale hunters.

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.

"Economic man" in cross-cultural perspective: behavioral experiments in 15 small-scale societies.

Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model - based on self-interest - fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life.