Center for Behavior, Evolution, and Culture

Sarah Mathew - Peer Sanctioning and Cultural Group Selection Promotes Large-Scale Cooperation: Evidence from Kenyan Pastoralists
2017-10-23 00:00 (America/Los_Angeles)
Sarah Mathew: Arizona State UniversityExplaining 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.

Michael Gurven - Do Costs of Reproduction Affect Human Survival?
2017-10-16 00:00
Michael Gurven: University of California, Santa BarbaraSex differences in human mortality and health are widely documented in both low and high income countries. Usual explanations focus on differences in intrinsic senescence, lifestyle, and health-seeking behaviors. Another possibility is that costs of reproduction unique to women may alter their physical condition in adulthood relative to men. Additionally, variability in the intensity of reproductive effort may account for health-related phenotypic differences among women. The underlying logic behind these propositions assumes a simple trade-off given a limited energetic budget where investments in reproductive effort subtract from those affecting maintenance and survival. In this talk, I develop and explore these ideas by assessing sex differences in adult health and physical condition among small-scale, natural fertility populations of hunter-gatherers and horticulturalists. I then attempt to uncover the effects of reproductive intensity on women’s health among Tsimane Amerindians – an attempt rife with the usual methodological obstacles due to self-selection and the absence of randomization. I discuss implications in light of social environmental context and declining fertility worldwide.

Lauren Schroeder - Skull Diversity Within the Homo Lineage
2017-10-09 00:00
Lauren Schroeder: University of Toronto Mississauga Our genus is characterized by a significant amount of morphological diversity, a phenomenon at the heart of the longstanding debate surrounding the origin and evolution of Homo. Recent fossil discoveries from Dmanisi, Georgia, Ledi-Geraru, Ethiopia, and the Cradle of Humankind in South Africa have expanded the range of morphological variation observed within our genus, leading to new questions surrounding the mosaic nature of morphological evolution. This presentation explores skull diversity within Homo, focusing on the possible evolutionary processes that may have driven such a degree of diversification and innovation.

William Audeh - Applying Evolutionary Biology to Make Progress in Cancer Medicine
2017-10-02 00:00
William Audeh : Cedars-Sinai Medical CenterPrinciples of Evolutionary Biology have been applied to the problem of cancer, primarily to explain why cancer develops. This approach has focused on intrinsic mutation rates and the stochastic risk of carcinogenesis, as well as the issue of “mismatch”, in which the argument is made that cancer arises because the human genome is mismatched and maladapted to the modern environment. What has been lacking until recently, however, is the practical application of evolutionary biology to guide the therapy of cancer in a clinically meaningful way. Cancer is understood and managed by clinicians as a clinical disease, rather than what evolutionary biology more correctly identifies it to be: a diverse population of cells undergoing active micro-evolution, adapting in response to the selective pressures of therapy and the tissue micro-environment, like an invasive species. The explosion of genomic information about cancer now allows a different, biologically-enlightened strategy to guide cancer therapy, based upon recognized principles of evolutionary biology and population genetics.
This is very similar in topic to the talk I gave at Grand Rounds for Darwinian Medicine Month in February, but will be modified and updated for a non-clinical audience.

Peter B. Gray - Sex, Babies, and Dogs: Evolutionary and Endocrine Aspects of Changing Human Families
2017-06-05 00:00
Peter B. Gray: University of Nevada, Las VegasCompared to great apes, several key features of human hunter-gatherer family life stand out: having more children at shorter inter-birth intervals, forming long-term reproductive partnerships, and investment by fathers and female relatives beyond their reproductive years. Behavioral reconstructions suggest derived features of human hunter-gatherer families evolved during the last several million years of Homo. As humans spread around the globe, a marvelous variety of human families has emerged and continues to change. Life history theory provides a functional approach, complemented by hormonal mechanisms, to structure how family members interact among themselves and with others. I discuss several key patterns intertwining human family change and hormones that differ from hunter-gatherer families. Almost all human children today are involved in formal education and many too in sports and school-based competitions organized by adults. How do adrenal hormones DHEA and androstenedione relate to children’s learning and social competition? In great apes and hunter-gatherers, the bulk of female reproductive years are spent pregnant or in lactational amenorrhea. Yet fertility has plummeted in much of the world and inter-birth intervals differ from ancestral conditions. How do hormonal shifts across pregnancy and postpartum impact maternal care and partnership dynamics, including sex lives, of parents? Fathers play variable roles across human families. Male involvement in family life is often linked to lower testosterone, and also involves oxytocin and prolactin. In some societies, dogs are increasingly viewed as family members, with several studies indicating that interactions with a dog can increase human oxytocin levels. Lastly, I speculate about patterns of female and male reproductive senescence and underlying hormonal mechanisms in relation to partnership maintenance and grandparenting.

Adrian Bell - Advancing Our Evolutionary Understanding of Migration
2017-05-22 00:00
Adrian Bell: University of UtahMost evolutionary ecological outcomes are highly sensitive to the nature of migration. The when, where, and how of migration are fundamental to evolutionary questions that anthropologists and others have tackled, though with varying levels of analytical rigor. In worst cases, migration is merely acknowledged as the elephant in the room. How can we do better! In this talk I discuss theoretical and empirical approaches that help us more rigorously explore the patterns of migration and measure its impact in prehistory and the present. I take examples from my theoretical work on the Ideal Despotic Distribution, ethnic markers, and the evolution of essentialism. I also discuss my empirical work on settlement patterns in the Pacific, and ongoing ethnographic work in Tonga and the Tongan diaspora. Throughout I advocate the balanced use of mathematical theory and empirical rigor as the way forward.

Anita Stone - From Juveniles to Adults: Life History Challenges and Strategies of Squirrel Monkeys
2017-05-15 00:00
Anita Stone: California Lutheran UniversityThe primate juvenile period has been considered a “limbo phase” with few evolutionary consequences, a view that has been challenged. In addition, it has been proposed that juvenility is a high-risk stage in which juveniles are at social and ecological disadvantages compared to adults in their group. Using field data from a population of squirrel monkeys (Saimiri collinsi) in Eastern Amazonia, Brazil, I evaluate the “riskiness” of the juvenile phase. These neotropical primates are small, show delayed maturation, are frugivorous-insectivorous and live in large social groups. Contrary to expectations, juveniles are at no disadvantage compared to larger and older adults, both in terms of time needed to acquire foraging skills or in competitive interactions with older conspecifics. I argue that in this genus of neotropical primate, adults face higher sociecological risks associated with reproductive challenges than do juveniles. I will then discuss the distinct life history pressures that affect adult male and adult female squirrel monkeys.

Claudia Valeggia - Life history (and other) transitions among the Qom of Argentina
2017-05-08 00:00
Claudia Valeggia: UC DavisThis talk will be about change and how we experience it. Humans go through several transitions during the course of their life. The transition from one life history phase to the next, e.g. from infancy to childhood or from reproductive to post-reproductive life, represents a physiological challenge as well as a sociocultural one. We have been evaluating the interaction among biocultural variables underlying key life history transitions and identifying the implicated trade-offs. With a different analytical focus, we are also interested in exploring transitions at a population level, like the ones indigenous communities are experiencing all over the world. For the last 20 years, we have been working with Qom and other indigenous communities in northern Argentina. Biological and ethnographic data are combined to understand the theoretical and applied components of these life and population transitions. I will present an overview of what we have learned so far and share some of the contributions we have made to evolutionary anthropology, human biology, biocultural studies, and global public health.

Kevin Langergraber - Group Augmentation, Collective Action, and Territorial Boundary Patrolling by Male Chimpanzees
2017-05-02 00:00
Kevin Langergraber: Arizona State UniversityMany animals carry out activities together because the benefits derived from collective action exceed those that can be achieved individually. But how can collective action evolve when individuals benefit from cooperation regardless of whether they pay its participation costs? According to one influential perspective, collective action problems are common, especially when groups are large, but may be solved when individuals who have more to gain from the collective good or can produce it at low costs provide it to others as a byproduct. Several results from a 20-year study of one of the most striking examples of collective action in non-human animals, territorial boundary patrolling by male chimpanzees, are consistent with these ideas: individual participation varied positively with both paternity success, i.e., the benefits, and dominance rank, i.e., a proxy for costs, and negatively with group size. Collective action theory nevertheless could not explain all our results because individual patrolling effort was higher and less variable than participation in intergroup aggression in other primate species, and males often patrolled when they had no offspring or maternal relatives in the group to protect. In addition, the aggregate patrolling effort of the group did not decrease with group size. These results are better explained by group augmentation theory, which proposes that individuals should bear the short-term costs of collective action even when they have little to gain immediately, if such action leads to increases in group size and ultimately long-term reproductive success.

Cristine H. Legare - The Evolution and Ontogeny of Cultural Learning
2017-05-01 00:00
Cristine H. Legare: University of Texas at AustinHumans display a wide repertoire of socially acquired and transmitted behaviors that vary substantially across populations. Information is accumulated and transferred within and across generations through the process of cumulative culture. What are the evolved psychological mechanisms that underlie cultural learning and how do they develop over the course of ontogeny? In a systematic program of mixed-methodological, comparative, and cross-cultural research, I study the human capacities to learn, create, and transmit culture, to shed light on the cognitive and cultural evolution of our species. The propensity for social learning provides the foundation for cumulative culture, and is both early developing and universal. Selective social learning mechanisms also afford the capacity to flexibly respond to diverse ontogenetic contexts and cultural ecologies. I describe the global diversity in childrearing practices, and present evidence for continuity and variability in the psychological capacities that enable cultural learning.

Chris Dunkel Schetter - Stress and Anxiety in Pregnancy: Consequences and Mechanisms for Birth and Beyond
2017-04-24 00:00
Chris Dunkel Schetter: University of California, Los AngelesIn this talk, Prof Dunkel Schetter will touch on conceptions of stress, background on birth outcomes, and summarize briefly findings on stress and preterm birth and low birthweight. She will present findings from her own program of work on pregnancy anxiety as a risk factor for preterm birth and the mechanisms in diverse ethnic, racial and SES women. She will also note some developmental effects of prenatal stress and anxiety, and briefly mention resilience to stress in pregnancy and intervention work.

Ketema Paul - The Ability to Recover from Sleep Loss is Regulated by Biological Clocks in Skeletal Muscle Tissue
2017-04-16 00:00
Ketema Paul: University of California, Los AngelesSleep loss can severely impair cognitive performance, yet the ability to recover from sleep loss is not well understood. Sleep regulatory mechanisms are assumed to lie exclusively within the brain mainly due to the strong behavioral manifestations of sleep. Whole-body disruptions of circadian biological clocks in mice are known to impair several aspects of sleep. Surprisingly, we found that circadian-dependent sleep phenotypes were not rescued by restoring clock function in the brains of these mice. Instead, we found that most of the impaired sleep phenotypes could be rescued by restoring circadian clock function exclusively in skeletal muscle. Additionally, selective overexpression or knockout of core circadian gene Bmal1 in skeletal muscle had distinct and opposing effects on sleep traits. The most robust effects of Bmal1 manipulation in skeletal muscle tissue were on the ability to recover from sleep loss. Overall, these results suggest that molecular mechanisms in the periphery in general, and skeletal muscle tissue in particular, have regulatory influences on sleep-wake mechanisms in the brain.

Jeffrey Schank - The Evolution of Fairness
2017-04-03 00:00
Jeffrey Schank: UC DavisThere are many theoretical approaches to explaining fairness, but explaining fairness without leverage (e.g., genetic relatedness, punishment, or retaliation) is especially challenging. The dictator game (DG) is a fairness game without leverage. One player, the dictator, is given a divisible quantity of some resource (typically money) and must decide how much to give a second player, the recipient. The recipient has no counter strategy, so the obvious rational solution to the DG is for the dictator to keep all of the resource and give none to the recipient. In experimental applications of the DG, to control for possible forms of leverage (e.g., relatedness, friendship, etc.), anonymity is maintained between players. Nevertheless, hundreds of experiments using the DG across cultures have shown that people, on average, share nearly 30% of a resource with an anonymous recipient. Theoretically, this result has proven difficult to explain because of the lack of leverage. For example, Hamilton’s rule, which is standardly used to explain altruism and cooperation at the level of the individual, does not formally apply. Using an agent-based model, I show that fairness can evolve among agents that naively and anonymously play the DG. I also show that this framework can be extended to its close cousin the ultimatum game, providing a better explanation of the available Empirical data than models that only rely on leverage.

Marco Del Giudice - A unifying framework for evolutionary psychopathology
2017-03-13 00:00
Marco Del Giudice: University of New MexicoEvolutionary approaches to psychopathology have generated many innovative models of specific mental disorders, as well as a growing empirical literature. However, the field as a whole remains highly fragmented, and has not yet produced a biologically grounded alternative to existing classification systems. In this talk I introduce a unifying framework for mental disorders based on life history concepts. The updated classification model I present distinguishes between fast spectrum conditions (e.g., antisocial/conduct disorders and schizophrenia), slow spectrum conditions (e.g., obsessive-compulsive personality disorder and a variant of autism), and defense activation disorders (e.g., depression and phobias). I illustrate how this approach can be used to draw functionally important distinctions within single diagnostic categories and make sense of broad patterns of comorbidity, developmental patterns, and epidemiological risk factors. Finally, I present simulation results showing that the life history model successfully reproduces the observed structure of mental disorders, including the internalizing-externalizing distinction and the emergence of a “p factor” of generalized susceptibility to psychopathology.

Adam Sparks - Who takes risks, and why?
2017-03-06 00:00
Adam Sparks: UCLAWho takes risks, and why? Does risk-taking in one context predict risk-taking in other contexts? Attempting to answer these questions, I present a general conceptual model of decision-making under risk that integrates two inter-related pathways to risk-taking. The need-based pathway describes strategic response to competitive disadvantages; the ability-based pathway exploits competitive advantages. This broad model may help to reconcile long-standing disagreements regarding the etiology of risk-taking, especially debates between advocates of domain-general or domain-specific approaches to risk. Further, collaborators and I have applied this model to generate and test novel predictions about individual differences in diverse psychological/behavioral phenomena: pathogen avoidance, mating preferences, moral judgment, and cooperation/conflict decisions. There remain many opportunities for integrating the evolutionarily-informed study of risk-taking with the study of putatively domain-specific psychological mechanisms (e.g. emotions) and behaviors.

Kim Hill - The evolution of human uniqueness
2017-02-27 00:00
Kim Hill: Arizona State University

Doug Jones - Kinship thinking as core cognition
2017-02-06 00:00
Doug Jones: University of Utah

Eric Schniter - The Long Life of Skill Development among Tsimane Forager Horticulturalists
2017-01-30 00:00
Eric Schniter: UC Santa BarbaraCollaborative research from the Tsimane Health and Life History Project has investigated whether age profiles of Tsimane skill development are consistent with life history theory predictions about the timing of productivity and reproduction. Life history models suggest that the especially long human lifespan co-evolved with large brains in a foraging niche where survival depends on complex skills requiring a great deal of learning and accumulated experience. We examined a range of essential Tsimane skills including childcare, food and craft production, music performance, and storytelling. Our results show that: (1) most essential skills are acquired prior to first reproduction, then developed further so that their productive returns meet the increasing demands of dependent offspring during adulthood; (2) as post-reproductive adults age beyond years of peak performance, they report developing additional conceptual and procedural proficiency, and, despite greater frailty, are consensually regarded as the most expert (especially in music and storytelling), consistent with their roles as providers and educators. We find that adults have accurate understandings of their skillsets and skill levels –an important awareness for social exchange, comparison, learning, and pedagogy. These findings extend our understanding of the evolved human life history by illustrating how changes in embodied capital and the needs of dependent offspring predict the development of complementary skills and services in a forager-horticulturalist economy.

Catherine Salmon - Evolutionary Perspectives on Anorexic Behavior: Ancestral Mechanisms in the Modern World UCLABEC
2017-01-16 00:00
Catherine Salmon: University of RedlandsA compelling puzzle of our modern world is the disturbing obsession of some women with body image and dieting. Why do so many women in North America place such an emphasis on being thin? Why do these desires lead to eating disorders in only some women? It is commonly assumed that the desire for a thin female physique and its pathological expression in eating disorders result from a social pressure for thinness. In recent years, anorexia nervosa and bulimia have become the most attention grabbing eating disorders with a multitude of studies being published from a variety of perspectives. With all this attention, one would think that we would have a concrete understanding of the causes of eating disorders and yet there have been a plethora of theories that have been proposed in the literature. In my talk, I will review several adaptationist approaches to the study of dieting behavior, focusing on my work with colleagues on the link between reproductive suppression, dieting, parental and social pressures, and life history strategy.

Patty Gowaty - Standing on Darwin’s Shoulders: Sexual Selection and Bateman’s Principles
2017-01-09 00:00
Patty Gowaty:

Noa Pinter-Wollman - Individual Variation in Collective Behavior
2016-11-28 00:00
Noa Pinter-Wollman: UCLAMany biological systems are aggregates of individuals working synergistically to achieve collective goals. In social insects, evolution acts on variation in the emergent collective behaviors of the colony. Variation among colonies in collective behavior can result from differences in their composition and/or from differences in the environments in which they reside. To understand how environment and group composition shape collective outcomes I study the causes and consequences of individual variation in the behavior of both workers and colonies of ants and social spiders. Using field and lab studies combined with computer simulations, image analysis, and social network theory I show that both behavioral composition and spatial constraints shape collective outcomes. For example, exploratory individuals increase a group’s ability to detect high-quality nest sites, and nest architecture influences collective foraging dynamics. These findings demonstrate that social and physical environments interact to influence complex biological processes.

Ian C. Gilby - Pan the hunter: Chimpanzee predation and human evolution
2016-11-21 00:00
Ian C. Gilby: Arizona State UniversityIn order to understand the causes and consequences of the significant increase in meat consumption in hominins, we must first make inferences about the behavior of the last common ancestor (LCA) of apes and humans. Chimpanzees, which regularly hunt vertebrates, are a valuable point of reference for understanding the possible range of behavior exhibited by the LCA. I use long-term data from three communities in Tanzania and Uganda to determine why and how chimpanzees hunt. While chimpanzees exhibit a wide range of cooperative abilities, I will argue that in the context of hunting, cognitively complex mechanisms involving delayed, social benefits and/or shared intentions explain only a small proportion of the cooperation observed in the wild. Therefore, reliance upon such mechanisms in humans evolved after our lineage split from the great apes. Additionally, I will discuss the constraints on hunting faced by female chimpanzees, and will argue that similar factors provided a foundation for the evolution of the sexual division of labor in hominins.

Dan Conroy-Beam - A Multidimensional Approach to Human Mate Selection
2016-11-14 00:00
Dan Conroy-Beam: UC Santa BarbaraHuman mating research is largely motivated by an assumption that mate choice is guided by mate preferences. But the field knows little about the psychology responsible for translating preferences into downstream outcomes. Stated differently, what do mate preferences do and how do they do it? I present data from a series of studies exploring these questions using two empirical strategies: agent-based models and research on actual mated couples. First, I use a model of human mate choice evolution to compare the evolvability of several alternative algorithms for integrating mate preferences in mate selection. The findings support a novel hypothesis: human mate preferences are integrated by a Euclidean algorithm that represents preferences and potential mates as points within a common multidimensional preference space. I then apply this novel Euclidean algorithm to test hypotheses concerning a variety mating outcomes—attraction to potential mates, mate selection, and the calibration of mate preferences. Findings reveal that (1) Euclidean distances from ideal mate preferences predict attraction to potential mates, (2) chosen mates tend to fall close to mate preferences in preference space, (3) Euclidean measures of mate value predict people’s ability to fulfill their mate preferences and attract desirable mates, and (4) people calibrate their ideal mate preferences to their mate value as measured by a Euclidean algorithm. These findings highlight the utility of a multidimensional, Euclidean model of mate preference psychology for understanding how human psychology translates mate preferences into downstream mating outcomes.

Barney Schlinger - Sexual Selection for Grace, Speed, Strength and, Oh Yes, Noise!
2016-11-07 00:00
Barney Schlinger: UCLAManakins are a clade of extraordinary neotropical birds. In many species, the brightly–colored males are polygynous, performing no parental care duties, but they gather into leks for courtship. Over the past 20 years, my lab has performed detailed behavioral studies of golden-collared manakins (Manacus vitellinus) of Panamanian rainforests. These males clear display courts (by moving debris more than double their own body weight) where they perform elaborate, athletic courtship dances that are visually stunning, especially when viewed in slow motion. As part of court defense and courtship, males produce explosive snapping sounds by powerfully and rapidly throwing their wings together so their wrists collide over their heads. We find that females prefer to copulate with those males whose displays are quick and accurate and noisy. Anatomical (skeletal and musculature) and physiological (neural and endocrine and cardiovascular) studies show that males have evolved a variety of specializations that enable these extreme behavioral phenotypes. I describe a subset of this body of work in the context of mate choice theory, the evolution of communication and the value of perceiving the gestalt of a single organism.

Andrew Whalen - Integrating Social Learning Into Models of Reinforcement Learning
2016-10-31 00:00
Andrew Whalen: University of EdinburghSocial learning and asocial learning are sometimes seen as two conflicting ways in which individuals make decisions and learn about the world around them. Increasingly research has found that instead of being two conflicting learning processes, individuals, including children, will combine social and asocial sources of information to make decisions. One approach to understanding how social information might be integrated into other learning processes is by studying already well established models of human and animal learning. We present work that tries to understand how social information might be integrated into models of reinforcement learning, particularly temporal difference (TD) learning. Using a series of simulations we demonstrate that, unlike other simulation studies that treat social and asocial learning separately, social learning is nearly always beneficial, and that small amounts of social learning allows for the formation of stable traditions of complex socially transmitted behaviors in artificial populations. To better understand how social and asocial information is combined in humans, we ran a series of experiments to analyze how social learning impacts reinforcement learning, and find that individuals use social learning both to choose the actions that they perform, and as a secondary reinforcer that alters the associations they build between actions and rewards. These results highlight the importance of understanding how social and asocial sources of information are integrated on fine temporal scales for understanding the evolution of social learning and human culture.

David Lawson - Is polygynous marriage a harmful cultural practice?
2016-10-17 00:00
David Lawson: University of California, Santa BarbaraRecent years have witnessed a widening commitment to achieving gender equality at a global scale, with corresponding, and often controversial, shifts in international and domestic policy. In developing world regions, this includes efforts to abolish long-held cultural institutions that are ostensibly harmful to women. Yet such efforts are largely driven by good intentions and ethnocentric rhetoric, rather than theoretically or empirically driven insights. In this talk I interrogate the claim that polygynous marriage in Sub-Saharan Africa represents a ‘harmful cultural practice’. Using evolutionary anthropology as a guiding theoretical framework, I review the extant literature on polygyny and its consequences and present the results of a recent study of marital status, food security and child health in Tanzania spanning over 50 villages. I conclude that polygynous marriage cannot be considered universally harmful, and that future research and policy must pay greater attention to identifying locally realizable alternatives and context dependency when considering the health implications of cultural practices.

Michelle Brown - Choose Your Battles: Individual Motivations for Participation in Collective Aggression
2016-10-10 00:00
Michelle Brown: University of California, Santa BarbaraGroup?level competition has important effects on individual fitness and is thought to be a crucial force in the evolution of complex social systems. However, such conflicts represent a collective action problem: if all group members share the spoils of battle but only a few incur the costs of fighting, why do participators tolerate free?riders and continue to provide a collective good? In humans, this problem is surmounted by punishing defectors and rewarding participants, but these mechanisms have not been observed in other group-living species. In a large-scale study of redtail monkeys (Cercopithecus ascanius) at the Ngogo site in Kibale National Park, Uganda, I test the underlying assumption that a collective action problem is an inherent feature of intergroup conflicts. In particular, I ask whether participants and defectors experience differing costs and similar benefits during conflicts, measured as changes in energy balance. My research indicates that individual motivations fluctuate over time, but individuals can nonetheless be categorized as either conditional participants or conditional defectors.

Gandhi Yetish - Sleep as an Evolved Behavior: Ecological Opportunity Costs and Sleep Optimization
2016-10-03 00:00
Gandhi Yetish: University of New MexicoShort
sleep duration is associated with numerous, sometimes severe, negative health outcomes, and yet many people report regularly sleeping insufficiently. Part of the challenge in improving poor health practice lies in the fact that a consensus definition of “good”
sleep remains lacking. In the scope of my dissertation research, I (with many collaborators) have sought to implement an evolutionary and ecological perspective to address this issue (in part). We argue that sleep is not only as a physiological state of being,
but as a behavior of sorts, regulated by shifting opportunity costs. In this talk, I will present three semi-independent studies that together test the hypothesis that sleep on any given night is a flexible phenotype (or reaction norm) that responds dynamically
to short-term needs. The first study presents findings from Yetish et al., 2015, which compares sleep among three independent small-scale societies (Hadza, San, Tsimane) to assess the degree to which post-industrial sleep patterns reflect a pathological shift
in chronic sleep patterns (answer: little, if at all). The second two studies present early findings from works-in-progress that test the effects on sleep from two different types of opportunity costs: productivity and vigilance. Using a mixture of accelerometry
(for objective sleep measurements) and quantitative ethnographic interviews (for behavioral insights), we investigated how the need to procure food and the degree of exposure in a sleeping site affect sleep patterns among Tsimane hunter-horticulturalists in
Amazonian Bolivia, and find support for the proposed opportunity cost tradeoff model of sleep optimization.

Jessica Lynch Alfaro - Comparative Phylogenomics, Biogeography and Conservation of Neotropical Primates
2016-09-26 00:00
Jessica Lynch Alfaro: UCLANeotropical primates represent one of the most successful mammalian radiations in the Neotropics, and all living platyrrhine monkeys in Central and South America stem from a single common ancestor from about 22 Ma. Neotropical primates exhibit extreme morphological and behavioral diversity, from the tiny pygmy marmoset to the ape-like muriqui, and they occupy not only rainforest habitats, but dry forests, savannah-like habitats, and high altitude geography in the Andes. However, about 45% of Neotropical primate taxa are now ‘red listed’ as threatened species by the IUCN, and more information is needed to characterize Neotropical primate biodiversity. Fortunately, studies on the phylogenetic relationships and evolutionary history of Neotropical primates have increased dramatically in recent years using collaborative international efforts at data collection and new techniques in genomics and biogeography. Here I present a comparative perspective of Neotropical primate biogeography, elucidating the geographic barriers, geologic events, and biotic factors most important to shape the primate diversity we see today. I also discuss the impact that phylogenomic and biogeographic studies have had on taxonomy and conservation priorities for this important Neotropical group, and consider what behavioral or life history attributes buffer some primates’ extinction risk in the face of anthropogenic change.

Anne Warlaumont - Modeling the Evolution and Development of Human Vocalization
2016-05-09 00:00
Anne Warlaumont: University of California, MercedHumans use a wide variety of types of vocal signals to communicate with other humans. Some of these sounds, such as crying, shrieking, and laughing, are thought to be closely related to those of our primate relatives. Others, especially babbling, speaking, and singing, appear to rely to a great extent on learning during infancy and early childhood. I will present a set of computational models that attempt to provide an account for how selection pressures and physiological mechanisms combined to create the adult human vocal repertoire.
