Social and Behavioral Sciences Commons^™

Increases In Regional Brain Volume Across Two Native South American Male Populations, Nikhil N. Chaudhari, Phoebe E. Imms, Nathan F. Chowdhury, Margaret Gatz, Benjamin Trumble, Wendy J. Mack, E. Meng Law, M. Linda Sutherland, James D. Sutherland, Christopher J. Rowan, L. Samuel Wann, Adel H. Allam, Randall C. Thompson, David E. Michalik, Michael I. Miyamoto, Guido Lombardi, Daniel Cummings, Edmond Seabright, Sarah Alami, Angela R. Garcia, Daniel E. Rodriguez, Raul Quispe Gutierrez, Adrian J. Copajira, Paul L. Hooper, Kenneth Buetow, Jonathan Stieglitz, Michael D. Gurven, Gregory S. Thomas, Hillard Kaplan, Caleb E. Finch, Andrei Irimia

ESI Publications

Industrialized environments, despite benefits such as higher levels of formal education and lower rates of infections, can also have pernicious impacts upon brain atrophy. Partly for this reason, comparing age-related brain volume trajectories between industrialized and non-industrialized populations can help to suggest lifestyle correlates of brain health. The Tsimane, indigenous to the Bolivian Amazon, derive their subsistence from foraging and horticulture and are physically active. The Moseten, a mixed-ethnicity farming population, are physically active but less than the Tsimane. Within both populations (N = 1024; age range = 46–83), we calculated regional brain volumes from computed tomography and compared …

Who Helps Tsimane Children And Adults?, Eric Schniter, Daniel K. Cummings, Paul L. Hooper, Maguin Gutierrez Cayuba, Jonathan Stieglitz, Benjamin C. Trumble, Hillard S. Kaplan, Michael D. Gurven

ESI Working Papers

We consider several forms of helping behavior among Tsimane Amerindians of Bolivia, including provision of shelter, childcare, food, sickcare, loans, advice, and cultural influence. While kin selection theory is traditionally invoked to explain nepotistic nurturing of youngsters by closely related kin, much less attention has been given to understanding the help provided to children and adults by individuals without close genetic relatedness. To explain who provides the various forms of help that we consider, we evaluate support for several predictions derived from kin selection theory: that helpers are most often closely related and from an older generation, provide more help …

Cultural Evolution: A Review Of Theoretical Challenges, Ryan Nichols, Mathieu Charbonneau, Azita Chellappoo, Taylor Davis, Miriam Haidle, Erik O. Kimbrough, Henrike Moll, Richard Moore, Thom Scott-Phillips, Benjamin Grant Purzycki, Jose Segovia-Martin

Economics Faculty Articles and Research

The rapid growth of cultural evolutionary science, its expansion into numerous fields, its use of diverse methods, and several conceptual problems have outpaced corollary developments in theory and philosophy of science. This has led to concern, exemplified in results from a recent survey conducted with members of the Cultural Evolution Society, that the field lacks ‘knowledge synthesis’, is poorly supported by ‘theory’, has an ambiguous relation to biological evolution and uses key terms (e.g. ‘culture’, ‘social learning’, ‘cumulative culture’) in ways that hamper operationalization in models, experiments and field studies. Although numerous review papers in the field represent and categorize …

Testosterone Is Positively Associated With Coronary Artery Calcium In A Low Cardiovascular Disease Risk Population, Benjamin Trumble, Jacob Negrey, Stephanie V. Koebele, Randall C. Thompson, L. Samuel Wann, Adel H. Allam, Bret Beheim, M. Linda Sutherland, James D. Sutherland, Daniel Eid Rodriguez, David E. Michalik, Chris J. Rowan, Guido P. Lombardi, Angela R. Garcia, Daniel K. Cummings, Edmond Seabright, Sarah Alami, Thomas S. Kraft, Paul L. Hooper, Kenneth Buetow, Andrei Irimia, Margaret Gatz, Jonathan Stieglitz, Michael D. Gurven, Hillard Kaplan, Gregory S. Thomas, Tsimane Health And Life History Project Teams

ESI Publications

Background

In industrialized populations, low male testosterone is associated with higher rates of cardiovascular mortality. However, coronary risk factors like obesity impact both testosterone and cardiovascular outcomes. Here, we assess the role of endogenous testosterone on coronary artery calcium in an active subsistence population with relatively low testosterone levels, low cardiovascular risk and low coronary artery calcium scores.

Methodology

In this cross-sectional community-based study, 719 Tsimane forager-horticulturalists in the Bolivian Amazon aged 40+ years underwent computed tomography (49.8% male, mean age 57.6 years).

Results

Coronary artery calcium levels were low; 84.5% had no coronary artery calcium. Zero-inflated negative binomial models …

First Approximation Of Population Distributions On The International Space Station, Justin St. P. Walsh, Rao Hamza Ali, Alice C. Gorman, Amir Kanan Kashefi

Art Faculty Articles and Research

This paper presents an analysis of data derived from thousands of publicly available photographs showing life on the International Space Station (ISS) between 2000 and 2020. Our analysis uses crew and locational information from the photographs’ metadata to identify the distribution of different population groups—by gender, nationality, and space agency affiliation—across modules of the ISS, for the first time. Given the significance of the ISS as the most intensively inhabited space habitat to date, an international cooperative initiative involving 26 countries and five space agencies, and one of the most expensive building projects ever undertaken by humans, developing an understanding …

Contact With Caregivers Is Associated With Composition Of The Infant Gastrointestinal Microbiome In The First 6 Months Of Life, Kyle S. Wiley, Andrew M. Gregg, Molly M. Fox, Venu Lagishetty, Curt A. Sandman, Jonathan P. Jacobs, Laura M. Glynn

Psychology Faculty Articles and Research

Objectives

Little is known about how physical contact at birth and early caregiving environments influence the colonization of the infant gastrointestinal microbiome. We investigated how infant contact with caregivers at birth and within the first 2 weeks of life relates to the composition of the gastrointestinal microbiome in a sample of U.S. infants (n = 60).

Methods

Skin-to-skin and physical contact with caregivers at birth and early caregiving environments were surveyed at 2 weeks postpartum. Stool samples were collected from infants at 2 weeks, 2, 6, and 12 months of age and underwent 16S rRNA sequencing as a proxy …

Metapopulation Dynamics Of Sars-Cov-2 Transmission In A Small-Scale Amazonian Society, Thomas Kraft, Edmond Seabright, Sarah Alami, Samuel M. Jenness, Paul L. Hooper, Bret Beheim, Helen Davis, Daniel K. Cummings, Daniel Eid Rodriguez, Maguin Gutierrez Cayuba, Emily J. Miner, Xavier De Lamballerie, Lucia Inchauste, Stéphane Priet, Benjamin Trumble, Jonathan Stieglitz, Hillard Kaplan, Michael Gurven

ESI Publications

The severity of infectious disease outbreaks is governed by patterns of human contact, which vary by geography, social organization, mobility, access to technology and healthcare, economic development, and culture. Whereas globalized societies and urban centers exhibit characteristics that can heighten vulnerability to pandemics, small-scale subsistence societies occupying remote, rural areas may be buffered. Accordingly, voluntary collective isolation has been proposed as one strategy to mitigate the impacts of COVID-19 and other pandemics on small-scale Indigenous populations with minimal access to healthcare infrastructure. To assess the vulnerability of such populations and the viability of interventions such as voluntary collective isolation, we …

Apolipoprotein-Ε4 Is Associated With Higher Fecundity In A Natural Fertility Population, Benjamin Trumble, Mia Charifson, Tom Kraft, Angela R. Garcia, Daniel K. Cummings, Paul L. Hooper, Amanda J. Lea, Daniel Eid Rodriguez, Stephanie V. Koebele, Kenneth Buetow, Bret Beheim, Riana Minocher, Maguin Gutierrez, Gregory S. Thomas, Margaret Gatz, Jonathan Stieglitz, Caleb E. Finch, Hillard Kaplan, Michael Gurven

ESI Publications

In many populations, the apolipoprotein-ε4 (APOE-ε4) allele increases the risk for several chronic diseases of aging, including dementia and cardiovascular disease; despite these harmful effects at later ages, the APOE-ε4 allele remains prevalent. We assess the impact of APOE-ε4 on fertility and its proximate determinants (age at first reproduction, interbirth interval) among the Tsimane, a natural fertility population of forager-horticulturalists. Among 795 women aged 13 to 90 (20% APOE-ε4 carriers), those with at least one APOE-ε4 allele had 0.3 to 0.5 more children than (ε3/ε3) …

Energetic Costs Of Testosterone In Two Subsistence Populations, Benjamin C. Trumble, Herman Pontzer, Jonathan Stieglitz, Daniel K. Cummings, Brian Wood, Melissa Emery Thompson, David Raichlen, Bret Beheim, Gandhi Yetish, Hillard Kaplan, Michael Gurven

ESI Publications

Objective

Testosterone plays a role in mediating energetic trade-offs between growth, maintenance, and reproduction. Investments in a high testosterone phenotype trade-off against other functions, particularly survival-enhancing immune function and cellular repair; thus only individuals in good condition can maintain both a high testosterone phenotype and somatic maintenance. While these effects are observed in experimental manipulations, they are difficult to demonstrate in free-living animals, particularly in humans. We hypothesize that individuals with higher testosterone will have higher energetic expenditures than those with lower testosterone.

Methods

Total energetic expenditure (TEE) was quantified using doubly labeled water in n = 40 Tsimane forager-horticulturalists …

Reproductive Inequality In Humans And Other Mammals, Cody T. Ross, Paul L. Hooper, Jennifer E. Smith, Adrian V. Jaeggi, Eric Alden Smith, Sergey Gavrilets, Fatema Tuz Zohora, John Ziker, Dimitris Xygalatas, Emily E. Wroblewski, Brian Wood, Bruce Winterhalder, Kai P. Willführ, Aiyana K. Willard, Kara Walker, Christopher Von Rueden, Eckart Voland, Claudia Valeggia, Bapu Vaitla, Samuel Urlacher, Mary Towner, Chun-Yi Sum, Lawrence S. Sugiyama, Karen B. Strier, Kathrine Starkweather, Daniel Major-Smith, Mary Shenk, Rebecca Sear, Edmond Seabright, Ryan Schacht, Brooke Scelza, Shane Scaggs, Jonathan Salerno, Caissa Revilla-Minaya, Daniel Redhead, Anne Pusey, Benjamin Grant Purzycki, Eleanor A. Power, Anne Pisor, Jenni Pettay, Susan Perry, Abigail E. Page, Luis Pacheco-Cobos, Kathryn Oths, Seung-Yun Oh, David Nolin, Daniel Nettle, Cristina Moya, Andrea Bamberg Migliano, Karl J. Mertens, Rita A. Mcnamara, Richard Mcelreath, Siobhan Mattison, Eric Massengill, Frank Marlowe, Felicia Madimenos, Shane Macfarlan, Virpi Lummaa, Roberto Lizarralde, Ruizhe Liu, Melissa A. Liebert, Sheina Lew-Levy, Paul Leslie, Joseph Lanning, Karen Kramer, Jeremy Koster, Hillard S. Kaplan, Bayarsaikhan Jamsranjav, A. Magdalena Hurttado, Kim Hill, Barry Hewlett, Samili Helle, Thomas Headland, Janet Headland, Michael Gurven, Gianluca Grimalda, Russell Greaves, Christopher D. Golden, Irene Godoy, Mhairi Gibson, Claire El Mouden, Mark Dyble, Patricia Draper, Sean Downey, Angelina L. Demarco, Helen Elizabeth Davis, Stefani Crabtree, Carmen Cortez, Heidi Colleran, Emma Cohen, Gregory Clark, Julia Clark, Mark A. Caudell, Chelsea E. Carminito, John Bunce, Adam Boyette, Samuel Bowles, Tami Blumenfield, Bret Beheim, Stephen Beckerman, Quentin Atkinson, Coren Apicella, Nurul Alam, Monique Borgerhoff Mulder

ESI Publications

To address claims of human exceptionalism, we determine where humans fit within the greater mammalian distribution of reproductive inequality. We show that humans exhibit lower reproductive skew (i.e., inequality in the number of surviving offspring) among males and smaller sex differences in reproductive skew than most other mammals, while nevertheless falling within the mammalian range. Additionally, female reproductive skew is higher in polygynous human populations than in polygynous nonhumans mammals on average. This patterning of skew can be attributed in part to the prevalence of monogamy in humans compared to the predominance of polygyny in nonhuman mammals, to the limited …

Atherosclerosis In Indigenous Tsimane: A Contemporary Perspective, Randall C. Thompson, Gregory S. Thomas, Angela D. Neuneubel, Ashna Mahadev, Benjamin Trumble, Edmond Seabright, Daniel K. Cummings, Jonathan Stieglitz, Michael Gurven, Hillard Kaplan

ESI Publications

The Horus and other research teams have found that atherosclerosis is not uncommon in ancient people through the study of their mummified remains (Murphy et al., 2003; Allam et al., 2009, 2011; Thompson et al., 2013, 2014). However, some have postulated that traditional hunter-gatherers are in some ways healthier than modern people and that they had very little atherosclerotic disease (O’Keefe et al., 2010). The aim of this study was to evaluate the burden of atherosclerosis in a population alive today but living a traditional lifestyle similar to that experienced by past populations. This led to the Tsimane Health and …

Natural Selection Of Immune And Metabolic Genes Associated With Health In Two Lowland Bolivian Populations, Amanda J. Lea, Angela Garcia, Jesusa Arevalo, Julien F. Ayroles, Kenneth Buetow, Steve W. Cole, Daniel Eid Rodriguez, Maguin Gutierrez, Heather M. Highland, Paul L. Hooper, Anne Justice, Thomas Kraft, Kari E. North, Jonathan Stieglitz, Hillard Kaplan, Benjamin C. Trumble, Michael Gurven

ESI Publications

A growing body of work has addressed human adaptations to diverse environments using genomic data, but few studies have connected putatively selected alleles to phenotypes, much less among underrepresented populations such as Amerindians. Studies of natural selection and genotype–phenotype relationships in underrepresented populations hold potential to uncover previously undescribed loci underlying evolutionarily and biomedically relevant traits. Here, we worked with the Tsimane and the Moseten, two Amerindian populations inhabiting the Bolivian lowlands. We focused most intensively on the Tsimane, because long-term anthropological work with this group has shown that they have a high burden of both macro and microparasites, as …

Cultural Transmission Vectors Of Essential Knowledge And Skills Among Tsimane Forager-Farmers, Eric Schniter, Hillard Kaplan, Michael Gurven

ESI Publications

Humans transmit cultural information to others in a variety of ways that can affect productivity, cultural success, and ultimately fitness. Not all potential transmitters are expected to be equally preferred by learners or equally willing to influence their culture acquisition. Across socioeconomic opportunities and ages in the human life course, costs and benefits to both learners and potential transmitters are expected to vary, affecting rates of culture transmission from different vectors. Here we examine reported patterns of culture transmission contributing to 92 essential skills among a sample of 421 Tsimane forager-farmers native to Bolivia. Consistent with the expectation that the …

Automated Identification Of Astronauts On Board The International Space Station: A Case Study In Space Archaeology, Rao Hamza Ali, Amir Kanan Kashefi, Alice C. Gorman, Justin St. P. Walsh, Erik J. Linstead

Art Faculty Articles and Research

We develop and apply a deep learning-based computer vision pipeline to automatically identify crew members in archival photographic imagery taken on-board the International Space Station. Our approach is able to quickly tag thousands of images from public and private photo repositories without human supervision with high degrees of accuracy, including photographs where crew faces are partially obscured. Using the results of our pipeline, we carry out a large-scale network analysis of the crew, using the imagery data to provide novel insights into the social interactions among crew during their missions.

Postorbital Discard And Chain Of Custody: The Processing Of Artifacts Returning To Earth From The International Space Station, Justin St. P. Walsh, Alice C. Gorman, Paola Castaño

Art Faculty Articles and Research

Few items that comprise the material culture of the International Space Station ever return to Earth. Most are left on the station or placed on cargo resupply ships that burn up on atmospheric re-entry. This fact presents a challenge for archaeologists who use material culture as their primary evidence. Together with a sociologist, we observed the processes that have been developed by NASA contractors to handle and return items that come back to Earth on the Cargo Dragon vehicle. We observed two missions, CRS-13 and CRS-14, in January and May 2018, respectively, traveling to the locations of work and interviewing …

Prevalence Of Dementia And Mild Cognitive Impairment In Indigenous Bolivian Forager-Horticulturalists, Margaret Gatz, Wendy J. Mack, Helena C. Chui, E. Meng Law, Giuseppe Barisano, M. Linda Sutherland, James D. Sutherland, Daniel Eid Rodriguez, Raul Quispe Gutierrez, Juan Copajira Adrian, Jesus Bani Cuata, Amy R. Borenstein, Ellen E. Waters, Andrei Irimia, Christopher J. Rowan, L. Samuel Wann, Adel H. Allam, Randall C. Thompson, Michael I. Miyamoto, David E. Michalik, Daniel K. Cummings, Edmond Seabright, Angela R. Garcia, Paul L. Hooper, Thomas S. Kraft, Caleb E. Finch, Gregory S. Thomas, Jonathan Stieglitz, Benjamin C. Trumble, Michael D. Gurven, Hillard Kaplan

ESI Publications

Introduction

We evaluated the prevalence of dementia and mild cognitive impairment (MCI) in indigenous Tsimane and Moseten, who lead a subsistence lifestyle.

Methods

Participants from population-based samples ≥ 60 years of age (n = 623) were assessed using adapted versions of the Modified Mini-Mental State Examination, informant interview, longitudinal cognitive testing and brain computed tomography (CT) scans.

Results

Tsimane exhibited five cases of dementia (among n = 435; crude prevalence = 1.2%, 95% confidence interval [CI]: 0.4, 2.7); Moseten exhibited one case (among n = 169; crude prevalence = 0.6%, 95% CI: 0.0, 3.2), all age ≥ 80 years. …

Human Milk Oligosaccharide Compositions Illustrate Global Variations In Early Nutrition, Anita Vinjamuri, Jasmine C. C. Davis, Sarah M. Totten, Lauren D. Wu, Laura D. Klein, Melanie Martin, Ea Quinn, Brooke Scelza, Alicia Breakey, Michael Gurven, Grazyna Jasienska, Hillard Kaplan, Claudia Valeggia, Katie Hinde, Jennifer T. Smilowitz, Robin M. Bernstein, Angela M. Zivkovic, Michael J. Barratt, Jeffrey I. Gordon, Mark A. Underwood, David A. Mills, J. Bruce German, Carlito B. Lebrilla

ESI Publications

Background

Human milk oligosaccharides (HMOs) are an abundant class of compounds found in human milk and have been linked to the development of the infant, and specifically the brain, immune system, and gut microbiome.

Objectives

Advanced analytical methods were used to obtain relative quantitation of many structures in approximately 2000 samples from over 1000 mothers in urban, semirural, and rural sites across geographically diverse countries.

Methods

LC-MS−based analytical methods were used to profile the compounds with broad structural coverage and quantitative information. The profiles revealed their structural heterogeneity and their potential biological roles. Comparisons of HMO compositions were made between …

Visual Displays In Space Station Culture: An Archaeological Analysis, Justin St. P. Walsh, Alice C. Gorman, Wendy Salmond

Art Faculty Articles and Research

We offer an archaeological analysis of the visual display of “space heroes” and Orthodox icons in the Russian Zvezda module of the International Space Station (ISS). This study is the first systematic investigation of material culture at a site in space. The ISS has now been continuously inhabited for 20 years. Here, focusing on the period 2000–2014, we use historic imagery from NASA archives to track the changing presence of 78 different items in a single zone. We also explore how ideas about which items are appropriate for display and where to display them originated in earlier Soviet and Russian …

Helminth Infection Is Associated With Dampened Cytokine Responses To Viral And Bacterial Stimulations In Tsimane Forager-Horticulturalists, India A. Schneider-Crease, Aaron D. Blackwell, Thomas S. Kraft, Melissa Emery Thompson, Ivan Maldonado Suarez, Daniel K. Cummings, Jonathan Stieglitz, Noah Snyder-Mackler, Michael Gurven, Hillard Kaplan, Benjamin C. Trumble

ESI Publications

Background

Soil-transmitted helminths (STHs) and humans share long co-evolutionary histories over which STHs have evolved strategies to permit their persistence by downregulating host immunity. Understanding the interactions between STHs and other pathogens can inform our understanding of human evolution and contemporary disease patterns. Methodology

We worked with Tsimane forager-horticulturalists in the Bolivian Amazon, where STHs are prevalent. We tested whether STHs and eosinophil levels—likely indicative of infection in this population—are associated with dampened immune responses to in vitro stimulation with H1N1 and lipopolysaccharide (LPS) antigens. Whole blood samples (n = 179) were treated with H1N1 vaccine and LPS and …

A Method For Space Archaeology Research: The International Space Station Archaeological Project, Justin St. P. Walsh, Alice C. Gorman

Art Faculty Articles and Research

How does a ‘space culture’ emerge and evolve, and how can archaeologists study such a phenomenon? The International Space Station Archaeological Project seeks to analyse the social and cultural context of an assemblage relating to the human presence in space. Drawing on concepts from contemporary archaeology, the project pursues a unique perspective beyond sociological or ethnographical approaches. Semiotic analysis of material culture and proxemic analysis of embodied space can be achieved using NASA's archives of documentation, images, video and audio media. Here, the authors set out a method for the study of this evidence. Understanding how individuals and groups use …

Infanticide And Human Self Domestication, Erik O. Kimbrough, Gordon M. Myers, Arthur J. Robson

Economics Faculty Articles and Research

"Our hypothesis, which is largely complementary to Wrangham, is that band elders engaged in infanticide and direct and indirect child homicide against the offspring of reactive aggressive adults through decisions during the foraging period of the Middle and Upper Pleistocene. We hypothesize that elders may have targeted the offspring of reactively aggressive males (and females) as retaliation for behaviors that were not good for the elders or their offspring and because surreptitiously killing the offspring of violent males was much less dangerous to the elders than killing the violent males. Such retaliation could have selected against reactive aggression as a …

Should The State Of Israel Pursue Krav Maga As An Intangible Cultural Heritage Of The Jewish People? History And Politics Say Yes., Guy Mor, Andrea Molle

Political Science Faculty Articles and Research

Krav Maga (‘contact combat’) is an Israeli combat discipline arguably one of the many intangible cultural heritages of Israel and the Jewish people. It has played a unique role in the (re)creation and preservation of the Jewish identity and the formation of the state of Israel.

Recently we observe a growing academic literature debating the role of martial arts in international affairs and domestic political processes. It is the scope of this paper to contribute to this proposing a framework for understanding Krav-Maga as a means of cultural diplomacy as seen in other nations.

Very Low Prevalence And Incidence Of Atrial Fibrillation Among Bolivian Forager-Farmers, Christopher J. Rowan, Michael A. Eskander, Edmond Seabright, Daniel Eid Rodriguez, Edhitt Cortez Linares, Raul Quispe Gutierrez, Juan Copajira Adrian, Daniel Cummings, Bret Beheim, Kirsten Tolstrup, Abinash Achrekar, Thomas Kraft, David E. Michalik, Michael I. Miyamoto, Adel H. Allam, L. Samuel Wann, Jagat Narula, Benjamin C. Trumble, Jonathan Stieglitz, Randall C. Thompson, Gregory S. Thomas, Hillard S. Kaplan, Michael D. Gurven

ESI Publications

Background: Atrial fibrillation is the most common arrhythmia in post-industrialized populations. Older age, hypertension, obesity, chronic inflammation, and diabetes are significant atrial fibrillation risk factors, suggesting that modern urban environments may promote atrial fibrillation.

Objective: Here we assess atrial fibrillation prevalence and incidence among tropical horticulturalists of the Bolivian Amazon with high levels of physical activity, a lean diet, and minimal coronary atherosclerosis, but also high infectious disease burden and associated inflammation.

Methods: Between 2005–2019, 1314 Tsimane aged 40–94 years (52% female) and 534 Moseten Amerindians aged 40–89 years (50% female) underwent resting 12-lead electrocardiograms to assess atrial fibrillation prevalence. …

Dim Sum And The Chinese Diaspora, Ashley Lee

Student Scholar Symposium Abstracts and Posters

Dim sum originated from the southern states of China, mainly Hong Kong and Guangdong. The Chinese cuisine has traveled to many places in the world today where Chinese immigrants have settled since the Chinese diaspora circa the 1960s. At the time, Chinese immigrants who came to America had to assimilate to the American culture by situating themselves in areas that had already existed, creating ethnic enclaves in Chinatown, Los Angeles. The heavy population of Chinese immigrants poured into the San Gabriel Valley, which created a bigger community for the Chinese and preserved the Chinese identity. It was easier for them …

Computed Tomography Shows High Fracture Prevalence Among Physically Active Forager-Horticulturalists With High Fertility, Jonathan Stieglitz, Benjamin C. Trumble, Horus Study Team, Caleb E. Finch, Dong Li, Matthew J. Budoff, Hillard Kaplan, Michael D. Gurven

ESI Publications

Modern humans have more fragile skeletons than other hominins, which may result from physical inactivity. Here, we test whether reproductive effort also compromises bone strength, by measuring using computed tomography thoracic vertebral bone mineral density (BMD) and fracture prevalence among physically active Tsimane forager-horticulturalists. Earlier onset of reproduction and shorter interbirth intervals are associated with reduced BMD for women. Tsimane BMD is lower versus Americans, but only for women, contrary to simple predictions relying on inactivity to explain skeletal fragility. Minimal BMD differences exist between Tsimane and American men, suggesting that systemic factors other than fertility (e.g. diet) do not …

The Dynamics Of Men's Cooperation And Social Status In A Small-Scale Society, Christopher Von Rueden, Daniel Redhead, Rick O'Gorman, Hillard Kaplan, Michael Gurven

ESI Publications

We propose that networks of cooperation and allocation of social status co-emerge in human groups. We substantiate this hypothesis with one of the first longitudinal studies of cooperation in a preindustrial society, spanning 8 years. Using longitudinal social network analysis of cooperation among men, we find large effects of kinship, reciprocity and transitivity in the nomination of cooperation partners over time. Independent of these effects, we show that (i) higher-status individuals gain more cooperation partners, and (ii) individuals gain status by cooperating with individuals of higher status than themselves. We posit that human hierarchies are more egalitarian relative to other …

Kinship Ties Across The Lifespan In Human Communities, Jeremy Koster, Dieter Lukas, David Nolin, Eleanor Power, Alexandra Alvergne, Ruth Mace, Cody T. Ross, Karen Kramer, Russell Graves, Mark Caudell, Shane Macfarlan, Eric Schniter, Robert Quinlan, Siobhan Mattison, Adam Reynolds, Chun Yi-Sim, Eric Massengill

ESI Publications

A hypothesis for the evolution of long post-reproductive lifespans in the human lineage involves asymmetries in relatedness between young immigrant females and the older females in their new groups. In these circumstances, inter-generational reproductive conflicts between younger and older females are predicted to resolve in favor of the younger females, who realize fewer inclusive fitness benefits from ceding reproduction to others. This conceptual model anticipates that immigrants to a community initially have few kin ties to others in the group, gradually showing greater relatedness to group members as they have descendants who remain with them in the group. We examine …

Rediscovering Brazil: The Marajoara Style In Modernist Art And Design, Alyson Brandes

Student Scholar Symposium Abstracts and Posters

During the Portuguese rule of Dom Pedro II until 1889, through the years of the First Brazilian Republic (1889-1930) and into the First Vargas Regime (1930-1945), Brazil struggled to solidify a strong national identity that would finally unify the country and legitimize its rich cultural heritage. The discovery and excavation of Marajó Island in the 1870s provided evidence of a great, ancient civilization, and inspired Brazilian Art Deco and early Modernist artists. Polychrome ceramic urns, vessels, and tangas (female pubic covers) were among the most abundant archaeological finds, many with zoomorphic and geometric motifs that show the cultural importance of …

The Formation Of Queer Consciousness In Gay, Latin, Men: How Experiences Affect The Lives Of Queer Latinos, Daniel Leon-Barranco

Student Scholar Symposium Abstracts and Posters

I am interested in investigating the question: How does experience, in a Latinx environment, affect the “coming out” process for queer, Latinx, men? Additionally, the aim of this research is to discover whether Queer Latinx peoples retain their cultural identity/consciousness or abandon it. This project is relevant to analyze whether Latinx culture impacts peoples to abstain from or retain their cultural identity/consciousness. I also hope that this research can prove whether an amalgamation of standpoint theory and Situated Knowledge can come together to affect the process of (re)claiming identity; as the Latinx man claims their sexual identity. This research aims …

Asian American Representation On Social Media Platforms, Ashley Lee

Student Scholar Symposium Abstracts and Posters

YouTube is a popular social media platform where anyone can make an account and post any kind of content. When YouTube launched in 2005-06, it has since allowed minorities easier access to create stories in an industry that has a history of exclusion and whitewashing, specifically speaking about Asian Americans. Asian American content creators, such as Wong Fu Productions, Michelle Phan, Ryan Higa, and many others use YouTube as an outlet to adapt existing stereotypes into entertainment while resisting whitewashing in Hollywood. By analyzing their large influence online, we try to better understand who consists of their target audience, either …