October 23 2017

UCLA's Center for Behavior, Evolution, and Culture Seminar Series

Peer Sanctioning and Cultural Group Selection Promotes Large-Scale Cooperation: Evidence from Kenyan Pastoralists

Sarah Mathew
Arizona State University

Explaining why humans cooperate in sizable groups requires detailed knowledge of how people cooperate in politically uncentralized societies. I will present findings from the Turkana, a politically uncentralized population of pastoralists in Kenya, which indicate that: a) the Turkana maintain costly large-scale cooperation in warfare through peer sanctioning of free riders; and b) Turkana norms regulating punishment mitigate the second-order free rider problem and promote group-beneficial punitive behavior. Additionally, with data from 750 individuals drawn from nine clans of four neighboring ethnolinguistic groups, the Turkana, Samburu, Rendille and Borana, I will show that: a) between-group cultural variation is sufficiently high for cultural group selection to operate; and b) the scale at which cultural variation is maintained can explain the scale at which people cooperate. This suite of patterns indicates that peer sanctioning and cultural group selection in combination played a key role in enabling large-scale cooperation in humans.

Monday, October 23
12:00-1:30 p.m.
Haines Hall 352, UCLA


October 30 2017

UCLA's Center for Behavior, Evolution, and Culture Seminar Series

Hormones, Sleep, and Health Over the Transition to Parenthood

Darby Saxbe
USC

Becoming a parent is transformative. This talk will review recent research on neuroendocrine and behavioral changes in new parents, including studies of longitudinal change and within-person linkage in testosterone, cortisol, sleep, and depression in both mothers and fathers.

Monday, October 30
12:00-1:30 p.m.
Haines Hall 352, UCLA


November 6 2017

UCLA's Center for Behavior, Evolution, and Culture Seminar Series

Is Moral Judgment Designed to Deter?

Robert Kurzban
University of Pennsylvania

Evolutionary psychologists are committed to the view that form follows function. This commitment carries an epistemic corollary: if a mechanism with a proposed function does not have the form that is required to perform that function, confidence in the proposed function should be reduced. The view that moralistic punishment – imposing costs on those who violate a moral norm – functions to deter harm requires that moralistic punishment have a number of features to implement that function. First, moralistic punishment should be desired and deployed (only) in cases in which agents intend that harm come about; without intent, harmful acts can’t be deterred. Second, the magnitude of punishment desired should relate systematically to the benefits perpetrators receive, in line with standard decision theory. Third, and related, no punishment should be desired when no harm is intended and no harm comes about; there should be no victimless norm violations. Fourth, whether and how much punishment is desired should depend only on the costs and benefits of perpetrators’ actions/inactions; how violations occur is irrelevant to deterrence. All four of these predicted features of moralistic punishment have been empirically falsified. In this talk, I will briefly review this evidence and discuss the implications.

Monday, November 6
12:00-1:30 p.m.
Haines Hall, UCLA


November 13 2017

UCLA's Center for Behavior, Evolution, and Culture Seminar Series

The Evolution and Ontogeny of Ethno-Linguistic Reasoning

Cristina Moya
UC Davis

While many social species are group living, linguistically or symbolically marked social groups, characterized by large repertoires of shared cultural norms and behaviours, are uniquely human. However, the evolutionary relevance and psychological underpinnings of such ethnic groups remains debated. In this talk, I will examine the possibility that the way humans learn about ethno-linguistic boundaries reveal the structure of adaptations for reasoning about these. I report on psychological and ethnographic research from the Quechua-Aymara border in the Peruvian altiplano, and cross-cultural comparative work that speak to these questions. Results reveal 1) the importance of distinguishing between functionally independent intergroup phenomena such as stereotyping and cooperation, 2) that children are prone to develop believe that linguistic boundaries are important and fixed, and 3) that cultural evolutionary processes are likely more important than genetically evolved biases in determining the form of ethnic boundaries. Further implications for models of human social evolution will be discussed.

Monday, November 13
12:00-1:30 p.m.
Haines Hall 352, UCLA


November 20 2017

UCLA's Center for Behavior, Evolution, and Culture Seminar Series

Extra-Community Relationships in Humans: From Tolerance to Transactions

Anne Pisor
Max Planck Institute for Evolutionary Anthropology

Relative to non-human primates, humans are heavily reliant on social connections beyond the boundaries of their local communities. However, individuals vary in the extent to which they exhibit interest in extra-community relationships. How did humans come to have such pronounced tolerance toward extra-community individuals, and what are the relevant payoffs that modulate interest in extra-community relationships? To address these questions, I first identify the incentive structures favoring tolerance in inter-group encounters in the Primate order. Turning to ethnographic and ethnohistoric data, I emphasize how incentives for encounter are even more pronounced in humans, often with high payoffs to forming enduring social relationships via inter-group encounters. I then focus on the instantiations of these relationships among three populations of Bolivian horticulturalists, for whom integration to the national economy is changing the affordances of these connections. I discuss the extent to which an individual’s interest in extra-community relationships varies with her opportunities for access to market goods, experience of resource shortfalls, and perceptions of the qualities of extra-community individuals as social partners. I conclude by identifying candidate ways forward, including how we might better document the existence of extra-community relationships in the field and formulate informed hypotheses about the relevant incentive structures favoring, or disfavoring, these relationships.

Monday, November 20
12:00-1:30 p.m.
Haines Hall 352, UCLA


November 27 2017

UCLA's Center for Behavior, Evolution, and Culture Seminar Series

Neural Encoding and Cognitive Consequences of Human Social Networks

Carolyn Parkinson
UCLA

The cognitive demands of navigating large groups comprised of many varied and enduring social bonds are thought to have significantly shaped human brain evolution. Yet, much remains to be understood about how the human brain tracks, encodes, and is influenced by the social networks in which it is embedded. The work presented in this talk integrates approaches from social psychology, cognitive neuroscience, and social network analysis in order to better understand how the structure of the social world is encoded in the human brain and the cognitive consequences of this structure.

Monday, November 27
12:00-1:30 p.m.
Haines Hall 352, UCLA