Other Economics Commons^™

Fascism Usa: Class And Identity Politics In The Age Of Trump, Marc Edelman

Publications and Research

This essay argues that Trump’s triumph in the 2024 presidential contest represents the consolidation of an oligarchical authoritarian project, backed by a multi-class and (surprisingly, for some) multi-racial electorate. It brought intensified state and freelance attacks on immigrants, labor unions, women, LGBTQ+ people, journalists, civil servants, assorted “political enemies,” and other groups that the MAGA movement targets. It is institutionalizing authoritarian governance structures in ways that will be exceedingly difficult to undo. The paper first addresses the experience of growing up in the shadow of fascism. It analyzes various sectors that supported Trump and the impacts of inflation, incumbency, economic …

Investigating The Relationship Between Noun Classes And Plant Folk Taxonomy In Chasu Language Of Kilimanjaro Region In Tanzania, Peter Rabson Mziray

Journal of Humanities and Social Sciences

The current study investigates the relationship between noun classes and plant folk taxonomy in Chasu (G 22). The study focuses on two objectives: the first objective is to describe the plant folk taxonomy in Chasu and the second objective is to determine the relationship between noun classes and plant folk taxonomy in Chasu. Data were collected from rural villages in Same and Mwanga districts by using free listing, field interviews (jungle-walk-and-identify), and written texts containing Chasu plant names. The findings reveal that Chasu folk taxonomy reflects different ethnobotanical categories; including a unique beginner which is mmea/mimea ‘plant(s)’, and three life …

Object Play In Tsimane Children: Implications For Sex-Specific Division Of Labour, Ava Moser, Michael D. Gurven, Hillard Kaplan, Benjamin C. Trumble, Jonathan Stieglitz, Paul Hooper, Daniel Cummings, Adrian Jaeggi, Kathelijne Koops

ESI Publications

Sex-specific division of labour and the associated use of different subsistence techniques by males (e.g. hunting) and females (e.g. gathering) has played an important role in shaping human societies. Skills needed in adulthood are practiced in play during childhood and object play has been proposed to foster tool-use skills necessary for adult subsistence techniques. Here, we investigated sex differences in the ontogeny of object play in Tsimane children in Bolivia to understand its potential role in shaping gender-specific adult roles. We used observational data (>80,000 scan samples) from nine Tsimane communities collected between 2002 and 2007. We analysed age …

Subjective Well-Being Across The Life Course Among Non-Industrialized Populations, Michael Gurven, Yoann Buoro, Daniel Eid Rodriguez, Katherine Sayre, Benjamin Trumble, Aili Pyhälä, Hillard Kaplan, Arild Angelsen, Jonathan Stieglitz, Victoria Reyes-Garcia

ESI Publications

Subjective well-being (SWB) is often described as being U-shaped over adulthood, declining to a midlife slump and then improving thereafter. Improved SWB in later adulthood has been considered a paradox given age-related declines in health and social losses. While SWB has mostly been studied in high-income countries, it remains largely unexplored in rural subsistence populations lacking formal institutions that reliably promote social welfare. Here, we evaluate the age profile of SWB among three small-scale subsistence societies (n = 468; study 1), forest users from 23 low-income countries (n = 6987; study 2), and Tsimane’ horticulturalists (n = …

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

ESI Working Papers

We examine various forms of helping behavior among Tsimane Amerindians of Bolivia, focusing on the provision of shelter, childcare, food, sickcare, cultural influence, and traditional story knowledge. Kin selection theory traditionally explains nepotistic nurturing of youth by closely related kin. However, less attention has been given to understanding the help provided by individuals without close genetic relatedness. To explain who provides various forms of help, we evaluate support for several predictions derived from kin selection theory. Our results show that helpers who are most often closely related and from an older generation tend to provide more costly forms of help …

Matrilineal Ethnic Affiliation And Female Empowerment: Investigating Attitudes Towards Female Autonomy And Health In Ivorian Households, Martine Hind Stølan

Master's Theses

Kinship structure is a fundamental aspect of anthropology, however, there is still a gap in literature on its impact on economic research, particularly regarding female autonomy and health. This study aims to address this gap by examining the influence of matrilineal ethnic affiliation on attitudes towards female autonomy and health within Ivorian households. Using data from the 2011 IPUMS Demographic and Health Survey for the Ivory Coast, using female responses, this study investigates the complex dynamics shaping attitudes towards female autonomy and access to health care. Analysis on these aspects is done using ordinary least squares (OLS) and logistic estimations. …

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 …

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 …

Motives For (In)Effective Giving: Comparing Rural And Urban Groups In South Africa., Luvuyo Bulelani Magwaza

Master's Theses

Different cultures have their own set of norms and values that not only shape people’s motives but also influences their decision making. What may be viewed as logical and ethical in one culture, may be seen as illogical or unethical in another. One area that is consistently affected by cross-cultural differences in motives is charitable giving. Recently, there has been an increase in interest around effective altruism— a social movement and philosophy that argues, people should give to charities that do the most good. Prior research that has found that people do not give based on efficiency; instead, people give …

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 …

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 …

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 …

Using Immersive Data Visualization To Highlight Changing Travel Patterns In Maine Due To Covid 19, Colleen Metcalf, Charlotte Aucoin

Thinking Matters Symposium

The impacts of COVID 19 are of top concern to tourism policy makers and stakeholders across Maine, as tourism plays a vital role in the state’s economy. This project shows the value of the Storymap to present, in an accessible and visually appealing way, the continuing research on how volunteered geographic information from social media can track changes in tourist’s movement and spending in Maine. The metadata from Flickr photos was used to examine where visitors spent time in the summer of 2020, revealing new patterns of tourism activity due to Covid-19 travel restrictions. In addition, we incorporate the results …

The Property Species: Mine, Yours, And The Human Mind, Bart J. Wilson

Economics Faculty Books and Book Chapters

"Arguing that neither the sciences nor the humanities synthesizes a full account of property, the book offers a cross-disciplinary compromise that is sure to be controversial: Property is a universal and uniquely human custom. Integrating cognitive linguistics with philosophy of property and a fresh look at property disputes in the common law, the book makes the case that symbolic-thinking humans locate the meaning of property within a thing. That is, all human beings and only human beings have property in things, and at its core, property rests on custom, not rights. Such an alternative to conventional thinking contends that the …

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 …

Variation Among Populations In The Immune Protein Composition Of Mother's Milk Reflects Subsistence Pattern, Laura D. Klein, Jincui Huang, Elizabeth A. Quinn, Melanie A. Martin, Alicia A. Breakey, Michael Gurven, Hillard Kaplan, Claudia Valeggia, Grazyna Jasienska, Brooke Scelza, Carlito B. Lebrilla, Katie Hinde

ESI Publications

Lay Summary: Adaptive immune proteins in mothers’ milk are more variable than innate immune proteins across populations and subsistence strategies. These results suggest that the immune defenses in milk are shaped by a mother’s environment throughout her life.

Background and objectives: Mother’s milk contains immune proteins that play critical roles in protecting the infant from infection and priming the infant’s developing immune system during early life. The composition of these molecules in milk, particularly the acquired immune proteins, is thought to reflect a mother’s immunological exposures throughout her life. In this study, we examine the composition of innate …

A Bit Like Cash: Understanding Cash-For-Bitcoin Transactions Through Individual Vendors, Stephanie J. Robberson, Mark R. Mccoy

Journal of Digital Forensics, Security and Law

As technology improves and economies become more globalized, the concept of currency has evolved. Bitcoin, a cryptographic digital currency, has been embraced as a secure and convenient type of money. Due to its security and privacy for the user, Bitcoin is a good tool for conducting criminal trades. The Financial Crimes Enforcement Network (FinCEN) has regulations in place to make identification information of Bitcoin purchasers accessible to law enforcement, but enforcing these rules with cash-for-Bitcoin traders is difficult. This study surveyed cash-for-Bitcoin vendors in Oklahoma, Texas, Arkansas, Missouri, Kansas, Colorado, and New Mexico to determine personal demographic information, knowledge of …

Marital Violence And Fertility In A Relatively Egalitarian High-Fertility Population, Jonathan Stieglitz, Benjamin C. Trumble, Hillard Kaplan, Michael Gurven

ESI Publications

Ultimate and proximate explanations of men’s physical intimate partner violence (IPV) against women have been proposed. An ultimate explanation posits that IPV is used to achieve a selfish fitness-relevant outcome, and predicts that IPV is associated with greater marital fertility. Proximate IPV explanations contain either complementary strategic components (for example, men’s desire for partner control), non-strategic components (for example, men’s self-regulatory failure), or both strategic and non-strategic components involving social learning. Consistent with an expectation from an ultimate IPV explanation, we find that IPV predicts greater marital fertility among Tsimané forager-horticulturalists of Bolivia (n = 133 marriages, 105 women). This …

Correction To: 'Greater Wealth Inequality, Less Polygyny: Rethinking The Polygyny Threshold Model', Cody T. Ross, Monique Borgerhoff Mulder, Seung-Yun Oh, Samuel Bowles, Bret Beheim, John Bunce, Mark Caudell, Gregory Clark, Heidi Colleran, Carmen Cortez, Patricia Draper, Russell D. Greaves, Michael Gurven, Thomas Headland, Janet Headland, Kim Hill, Barry Hewlett, Hillard Kaplan, Jeremy Koster, Karen Kramer, Frank Marlowe, Richard Mcelereath, David Nolin, Marsha Quinlan, Robert Quinlan, Caissa Revilla-Minaya, Brooke Scelza, Ryan Schacht, Mary Shenk, Ray Uehara, Eckart Voland, Kai Willführ, Bruce Winterhalder, John Ziker, Christopher Von Rueden

ESI Publications

No abstract provided.

Greater Wealth Inequality, Less Polygyny: Rethinking The Polygyny Threshold Model, Cody T. Ross, Monique Borgerhoff Mulder, Seung-Yun Oh, Samuel Bowles, Bret Beheim, John Bunce, Mark Caudell, Gregory Clark, Heidi Colleran, Carmen Cortez, Patricia Draper, Russell D. Greaves, Michael Gurven, Thomas Headland, Janet Headland, Kim Hill, Barry Hewlett, Hillard Kaplan, Jeremy Koster, Karen Kramer, Frank Marlowe, Richard Mcelreath, David Nolin, Marsha Quinlan, Robert Quinlan, Caissa Revilla-Minaya, Brooke Scelza, Ryan Schacht, Mary Shenk, Ray Uehara, Eckart Voland, Kai Willführ, Bruce Winterhalder, John Ziker, Christopher Von Rueden

ESI Publications

Monogamy appears to have become the predominant human mating system with the emergence of highly unequal agricultural populations that replaced relatively egalitarian horticultural populations, challenging the conventional idea—based on the polygyny threshold model—that polygyny should be positively associated with wealth inequality. To address this polygyny paradox, we generalize the standard polygyny threshold model to a mutual mate choice model predicting the fraction of women married polygynously. We then demonstrate two conditions that are jointly sufficient to make monogamy the predominant marriage form, even in highly unequal societies. We assess if these conditions are satisfied using individual-level data from 29 human …

Sex Differences In Political Leadership In An Egalitarian Society, Christopher Von Rueden, Sarah Alami, Hillard Kaplan, Michael Gurven

ESI Publications

We test the contribution of sex differences in physical formidability, education, and cooperation to the acquisition of political leadership in a small-scale society. Among forager-farmers from the Bolivian Amazon, we find that men are more likely to exercise different forms of political leadership, including verbal influence during community meetings, coordination of community projects, and dispute resolution. We show that these differences in leadership are not due to gender per se but are associated with men’s greater number of cooperation partners, greater access to schooling, and greater body size and physical strength. Men’s advantage in cooperation partner number is tied to …

Low Perceived Control Over Health Is Associated With Lower Treatment Uptake In A High Mortality Population Of Bolivian Forager-Farmers, Sarah Alami, Jonathan Stieglitz, Hillard Kaplan, Michael Gurven

ESI Publications

Indigenous people worldwide suffer from higher rates of morbidity and mortality than neighboring populations. In addition to having limited access to public health infrastructure, indigenous people may also have priorities and health perceptions that deter them from seeking adequate modern healthcare. Here we propose that living in a harsh and unpredictable environment reduces motivation to pursue deliberate, costly action to improve health outcomes. We assess whether variation in Health Locus of Control (HLC), a psychological construct designed to capture self-efficacy with respect to health, explains variation in treatment uptake behavior among Tsimane Amerindians (N=690; age range: 40–89 years; 55.8% female; …

Information Transmission And The Oral Tradition: Evidence Of A Late-Life Service Niche For Tsimane Amerindians, Eric Schniter, Nathaniel T. Wilcox, Bret A. Beheim, Hillard S. Kaplan, Michael Gurven

ESI Publications

Storytelling can affect wellbeing and fitness by transmitting information and reinforcing cultural codes of conduct. Despite their potential importance, the development and timing of storytelling skills, and the transmission of story knowledge have received minimal attention in studies of subsistence societies that more often focus on food production skills. Here we examine how storytelling and patterns of information transmission among Tsimane forager-horticulturalists are predicted by the changing age profiles of storytellers’ abilities and accumulated experience. We find that storytelling skills are most developed among older adults who demonstrate superior knowledge of traditional stories and who report telling stories most. We …

Coronary Atherosclerosis In Indigenous South American Tsimane: A Cross-Sectional Cohort Study, Hillard Kaplan, Randall C. Thompson, Benjamin C. Trumble, L. Samuel Wann, Adel H. Allam, Bret Beheim, Bruno Frohlich, M. Linda Sutherland, James D. Sutherland, Jonathan Stieglitz, Daniel Eid Rodriguez, David E. Michalik, Chris J. Rowan, Guido P. Lombardi, Ram Bedi, Angela R. Garcia, James K. Min, Jagat Narula, Caleb E. Finch, Michael Gurven, Gregory S. Thomas

ESI Publications

Background—Conventional coronary artery disease risk factors might potentially explain at least 90% of the attributable risk of coronary artery disease. To better understand the association between the pre-industrial lifestyle and low prevalence of coronary artery disease risk factors, we examined the Tsimane, a Bolivian population living a subsistence lifestyle of hunting, gathering, fishing, and farming with few cardiovascular risk factors, but high infectious inflammatory burden.

Methods—We did a cross-sectional cohort study including all individuals who self-identified as Tsimane and who were aged 40 years or older. Coronary atherosclerosis was assessed by coronary artery calcium (CAC) scoring done with …

The Tsimane Health And Life History Project: Integrating Anthropology And Biomedicine, Michael Gurven, Jonathan Stieglitz, Benjamin C. Trumble, Aaron D. Blackwell, Bret Beheim, Helen Davis, Hillard Kaplan, Paul L. Hooper

ESI Publications

The Tsimane Health and Life History Project, an integrated bio-behavioral study of the human life course, is designed to test competing hypotheses of human life-history evolution. One aim is to understand the bidirectional connections between life history and social behavior in a highfertility, kin-based context lacking amenities of modern urban life (e.g. sanitation, banks, electricity). Another aim is to understand how a high pathogen burden influences health and well-being during development and adulthood. A third aim addresses how modernization shapes human life histories and sociality. Here we outline the project’s goals, history, and main findings since its inception in 2002. …

Horticultural Activity Predicts Later Localized Limb Status In A Contemporary Pre-Industrial Population, Jonathan Stieglitz, Benjamin C. Trumble, Hillard Kaplan, Michael Gurven

ESI Publications

Objectives—Modern humans may have gracile skeletons due to low physical activity levels and mechanical loading. Tests using prehistoric skeletons are limited by the inability to assess behaviour directly, while modern industrialized societies possess few socio-ecological features typical of human evolutionary history. Among Tsimane forager-horticulturalists, we test whether greater activity levels and, thus, increased loading earlier in life are associated with greater later-life bone status and diminished age-related bone loss.

Materials and Methods—We used quantitative ultrasonography to assess radial and tibial status among adults aged 20+ years (mean±SD age=49±15; 52% female). We conducted systematic behavioural observations to assess earlier-life …

Human Grooming In Comparative Perspective: People In Six Small-Scale Societies Groom Less But Socialize Just As Much As Expected For A Typical Primate, Adrian V. Jaeggi, Karen Kramer, Raymond Hames, Evan J. Kiely, Cristina Gomes, Hillard Kaplan, Michael Gurven

ESI Publications

Objectives—Grooming has important utilitarian and social functions in primates but little is known about grooming and its functional analogues in traditional human societies. We compare human grooming to typical primate patterns to test its hygienic and social functions.

Materials and Methods—Bayesian phylogenetic analyses were used to derive expected human grooming time given the potential associations between grooming, group size, body size, terrestriality, and several climatic variables across 69 primate species. This was compared against observed times dedicated to grooming, other hygienic behavior and conversation among the Maya, Pumé, Sanöma, Tsimane’, Yanomamö, and Ye’kwana (mean number of behavioral scans …

Cognitive Performance Across The Life Course Of Bolivian Forager-Farmers With Limited Schooling, Michael Gurven, Eric Fuerstenberg, Benjamin C. Trumble, Jonathan Stieglitz, Bret Beheim, Helen Davis, Hillard Kaplan

ESI Publications

Cognitive performance is characterized by at least two distinct life course trajectories. Many cognitive abilities (e.g. “effortful processing” abilities including fluid reasoning, and processing speed) improve throughout early adolescence and start declining in early adulthood, while other abilities (e.g. “crystallized” abilities like vocabulary breadth) improve throughout adult life, remaining robust even at late ages. Although schooling may impact performance and cognitive “reserve”, it has been argued that these age patterns of cognitive performance are human universals. Here we examine age patterns of cognitive performance among Tsimane forager-horticulturalists of Bolivia, and test whether schooling is related to differences in cognitive performance …

Growth References For Tsimane Forager-Horticulturalists Of The Bolivian Amazon, Aaron D. Blackwell, Samuel S. Urlacher, Bret Beheim, Christopher Von Rueden, Adrian V. Jaeggi, Jonathan Stieglitz, Benjamin C. Trumble, Michael Gurven, Hillard Kaplan

ESI Publications

Objectives—Growth standards and references currently used to assess population and individual health are derived primarily from urban populations, including few individuals from indigenous or subsistence groups. Given environmental and genetic differences, growth may vary in these populations. Thus, there is a need to assess whether international standards are appropriate for all populations, and to produce population specific references if growth differs. Here we present and assess growth references for the Tsimane, an indigenous population of Bolivian forager-horticulturalists.

Methods—Mixed cross-sectional/longitudinal anthropometrics (9,614 individuals; 30,118 observations; ages 0–29 years) were used to generate centile curves and Lambda-Mu-Sigma (LMS) tables for …