Arts and Humanities Commons^™

How Universal Is The Big Five? Testing The Five-Factor Model Of Personality Variation Among Forager-Farmers In The Bolivian Amazon, Michael Gurven, Christopher Von Rueden, Maxim Massenkoff, Hillard Kaplan, Marino Lero Vie

ESI Publications

The five-factor model (FFM) of personality variation has been replicated across a range of human societies, suggesting the FFM is a human universal. However, most studies of the FFM have been restricted to literate, urban populations, which are uncharacteristic of the majority of human evolutionary history. We present the first test of the FFM in a largely illiterate, indigenous society. Tsimane forager–horticulturalist men and women of Bolivia (n = 632) completed a translation of the 44-item Big Five Inventory (Benet-Martínez & John, 1998), a widely used metric of the FFM. We failed to find robust support for the FFM, based …

Modernization, Sexual Risk-Taking, And Gynecological Morbidity Among Bolivian Forager-Horticulturalists, Jonathan Stieglitz, Aaron D. Blackwell, Raúl Quispe Gutierrez, Edhitt Cortez Linares, Michael Gurven, Hillard Kaplan

ESI Publications

Sexual risk-taking and reproductive morbidity are common among rapidly modernizing populations with little material wealth, limited schooling, minimal access to modern contraception and healthcare, and gendered inequalities in resource access that limit female autonomy in cohabiting relationships. Few studies have examined how modernization influences sexual risk-taking and reproductive health early in demographic transition. Tsimane are a natural fertility population of Bolivian forager-farmers; they are not urbanized, reside in small-scale villages, and lack public health infrastructure. We test whether modernization is associated with greater sexual risk-taking, report prevalence of gynecological morbidity (GM), and test whether modernization, sexual risk-taking and parity are …

Why Do Women Have More Children Than They Want? Understanding Differences In Women's Ideal And Actual Family Size In A Natural Fertility Population, Lisa Mcallister, Michael Gurven, Hillard Kaplan, Jonathan Stieglitz

ESI Publications

Objectives—We develop and test a conceptual model of factors influencing women’s ideal family size (IFS) in a natural fertility population, the Tsimane of Bolivia. The model posits affects of socioecology, reproductive history, maternal condition, and men’s IFS. We test three hypotheses for why women may exceed their IFS despite experiencing socioeconomic development: (H1) limited autonomy; (H2) improved maternal condition; and (H3) low returns on investments in embodied capital.

Methods—Women’s reproductive histories and prospective fertility data were collected from 2002 to 2008 (n = 305 women). Semistructured interviews were conducted with Tsimane women to study the perceived value of …

Fatty Acid Composition In The Mature Milk Of Bolivian Forager-Horticulturalists: Controlled Comparisons With A Us Sample, Melanie A. Martin, William D. Lassek, Steven J. C. Gaulin, Rhobert W. Evans, Sheela S. Geraghty, Barbara S. Davidson, Ardythe L. Morrow, Hillard Kaplan, Michael Gurven

ESI Publications

Breast milk fatty acid (FA) composition varies greatly among individual women, including in percentages of the long-chain polyunsaturated FAs (LCPUFA) 20:4n-6 (arachidonic acid, AA) and 22:6n-3 (docosahexaenoic acid, DHA), which are important for infant neurological development. It has been suggested that owing to wide variation in milk LCPUFA and low DHA in Western diets, standards of milk FA composition should be derived from populations consuming traditional diets. We collected breast milk samples from Tsimane women at varying lactational stages (6–82 weeks). The Tsimane are an indigenous, natural fertility, subsistence-level population living in Amazonia Bolivia. Tsimane samples were matched by lactational …

From The Womb To The Tomb: The Role Of Transfers In Shaping The Evolved Human Life History, Michael Gurven, Jonathan Stieglitz, Paul L. Hooper, Cristina Gomes, Hillard Kaplan

ESI Publications

Humans are the longest living and slowest growing of all primates. Although most primates are social, humans are highly cooperative and social in ways that likely co-evolved with the slow human life history. In this paper we highlight the role of resource transfers and non-material assistance within and across generations in shaping low human mortality rates. The use of complex cooperative strategies to minimize risk is a necessary precursor for selecting further reductions in mortality rate in late adulthood. In conjunction with changes in the age-profile of production, the impacts of resource transfers and other forms of cooperation on reducing …

Infidelity, Jealousy, And Wife Abuse Among Tsimane Forager-Farmers: Testing Evolutionary Hypotheses Of Marital Conflict, Jonathan Stieglitz, Michael Gurven, Hillard Kaplan, Jeffrey Winking

ESI Publications

What causes marital conflict, and which marital conflicts are more likely to result in men’s violence against their wives? It has long been argued that men’s jealousy over women’s infidelity is the strongest impetus to men’s lethal and non-lethal violence against female partners. Less is known about the extent to which women’s jealousy over men’s infidelity precipitates men’s violence against female partners. Husbands are more likely than wives to commit infidelity, and men and women report a similar frequency and intensity of jealous emotions during recalls of potential infidelity. If men are likely to use time and resources for pursuit …

Evidence For A Peak Shift In A Humoral Response To Helminths: Age Profiles Of Ige In The Shuar Of Ecuador, The Tsimane Of Bolivia, And The U.S. Nhanes, Aaron D. Blackwell, Michael D. Gurven, Lawrence S. Sugiyama, Felicia C. Madimenos, Melissa A. Liebert, Melanie A. Martin, Hillard Kaplan, J. Josh Snodgrass

ESI Publications

Background: The peak shift model predicts that the age-profile of a pathogen’s prevalence depends upon its transmission rate, peaking earlier in populations with higher transmission and declining as partial immunity is acquired. Helminth infections are associated with increased immunoglobulin E (IgE), which may convey partial immunity and influence the peak shift. Although studies have noted peak shifts in helminths, corresponding peak shifts in total IgE have not been investigated, nor has the age-patterning been carefully examined across populations. We test for differences in the agepatterning of IgE between two South American forager-horticulturalist populations and the United States: the Tsimane …

Inflammatory Gene Variants In The Tsimane, An Indigenous Bolivian Population With A High Infectious Load, Sarinnapha Vasunilashorn, Caleb E. Finch, Eileen M. Crimmins, Suvi A. Vikman, Jonathan Stieglitz, Michael Gurven, Hillard Kaplan, Hooman Allayee

ESI Publications

The Tsimane of lowland Bolivia are an indigenous forager-farmer population living under conditions resembling pre-industrial European populations, with high infectious morbidity, high infection and inflammation, and shortened life expectancy. Analysis of 917 persons ages 5 to 60+ showed that allele frequencies of 9 SNPs examined in the apolipoprotein E (apoE), C-reactive protein (CRP), and interleukin-6 (IL-6) genes differed from some European, African, and north Asian-derived populations. The apoE2 allele was absent, whereas four SNPs related to CRP and IL-6 were monomorphic: CRP (rs1800947, rs3093061, and rs3093062) and IL-6 (rs1800795). No significant differences in apoE, CRP, and IL-6 variants across age …

Father Death And Adult Success Among The Tsimane: Implications For Marriage And Divorce, Jeffrey Winking, Michael Gurven, Hillard Kaplan

ESI Publications

Human fathers are heavily involved in the rearing of children around the world. While there is great cross-cultural variation, the father is a recognizable role in all populations. This deviates from the standard mammalian pattern of little paternal investment. A logical explanation offered early by evolutionary theorists is that human fathers evolved the capacity for paternal concern because human children are remarkably needy and impose a great encumbrance on the mother (Lancaster & Lancaster, 1983; Lovejoy, 1981). Thus, fathers have greater opportunity to enhance the wellbeing of child and mother, as there is a deeper well of need to fill. …

Blood Lipids, Infection, And Inflammatory Markers In The Tsimane Of Bolivia, Sarinnapha Vasunilashorn, Eileen M. Crimmins, Jung Ki Kim, Jeff Winking, Michael Gurven, Hillard Kaplan, Caleb Finch

ESI Publications

Objectives—Little is known about blood cholesterol (blood-C) levels under conditions of infection and limited diet. This study examines blood-C and markers of infection and inflammation in the Tsimane of the Bolivian Amazon, indigenous forager farmers living in conditions that model preindustrial European populations by their short life expectancy, high load of infections and inflammation, and limited diets.

Methods—We use multivariate models to determine the relationships between lipid levels and markers of infection and inflammation. Adult Tsimane (N = 418, age 20–84) were characterized for blood lipids, cells, and inflammatory markers in relation to individual loads of parasites and …

The Social Strategy Game: Resource Competition Within Female Social Networks Among Small-Scale Forager-Horticulturalists, Stacey L. Rukas, Michael Gurven, Hillard Kaplan, Jeffrey Winking

ESI Publications

This paper examines social determinants of resource competition among Tsimane Amerindian women of Bolivia. We introduce a semi-anonymous experiment (the Social Strategy Game) designed to simulate resource competition among women. Information concerning dyadic social relationships and demographic data were collected to identify variables influencing resource competition intensity, as measured by the number of beads one woman took from another. Relationship variables are used to test how the affiliative or competitive aspects of dyads affect the extent of prosociality in the game. Using a mixed-modeling procedure, we find that women compete with those with whom they are quarreling over accusations of …

Inflammation And Infection Do Not Promote Arterial Aging And Cardiovascular Disease Risk Factors Among Lean Horticulturalists, Michael Gurven, Hillard Kaplan, Jeffrey Winking, Daniel Eid Rodriguez, Sarinnapha Vasunilashorn, Jung Ki Kim, Caleb Finch, Eileen M. Crimmins

ESI Publications

Background: Arterial aging is well characterized in industrial populations, but scantly described in populations with little access to modern medicine. Here we characterize health and aging among the Tsimane, Amazonian forager-horticulturalists with short life expectancy, high infectious loads and inflammation, but low adiposity and robust physical fitness. Inflammation has been implicated in all stages of arterial aging, atherogenesis and hypertension, and so we test whether greater inflammation associates with atherosclerosis and CVD risk. In contrast, moderate to vigorous daily activity, minimal obesity, and low fat intake predict minimal CVD risk among older Tsimane.

Methods and Findings: Peripheral arterial …

A Bioeconomic Approach To Marriage And The Sexual Division Of Labor, Michael Gurven, Jeffrey Winking, Hillard Kaplan, Christopher Von Rueden, Lisa Mcallister

ESI Publications

Children may be viewed as public goods whereby both parents receive equal genetic benefits yet one parent often invests more heavily than the other.We introduce a microeconomic framework for understanding household investment decisions to address questions concerning conflicts of interest over types and amount of work effort among married men and women. Although gains and costs of marriage may not be spread equally among marriage partners, marriage is still a favorable, efficient outcome under a wide range of conditions. This bioeconomic framework subsumes both cooperative and conflictive views on the sexual division of labor. We test hypotheses concerning marriage markets, …

The Multiple Dimensions Of Male Social Status In An Amazonian Society, Christopher Von Rueden, Michael Gurven, Hillard Kaplan

ESI Publications

"In all human societies, individuals differ in social status depending upon their age and personal ability (Sahlins, 1958; Service, 1971). In laboratory-based small group studies, status hierarchies emerge spontaneously (Bass, 1954; Campbell et al., 2002; Kalma, 1991). Even among “egalitarian” foragers, who are characterized by widespread resource sharing (Kaplan & Gurven, 2005; Winterhalder, 1986) and some degree of status-leveling (Cashdan, 1980), certain individuals consume more resources, get the best pick of mates, and take a more central role in group decision-making (Boehm, 1999; Trigger, 1985; Wiessner, 1996). Whether implicit or overt, classification by social status is a human universal. While …

Aging And Inflammation In Two Epidemiological Worlds, Michael Gurven, Hillard Kaplan, Jeffrey Winking, Caleb Finch, Eileen M. Crimmins

ESI Publications

Humans evolved in a world with high levels of infection resulting in high mortality across the life span and few survivors to advanced ages. Under such conditions, a strong acute-phase inflammatory response was required for survival; however, inflammatory responses can also promote chronic diseases of aging. We hypothesize that global historical increases in life span at older ages are partly explained by reduced lifetime exposure to infection and subsequent inflammation. To begin a test of this hypothesis, we compare C-reactive protein (CRP); levels in two populations with different epidemiological environments: the Tsimane of Bolivia and persons in the United States. …

Images Of God: The Effect Of Personal Theologies On Moral Attitudes, Political Affiliation, And Religious Behavior, Christoper Bader, Paul Froese

Sociology Faculty Articles and Research

Social scientists often explain religious effects in terms of religious group affiliations. Typically, researchers identify religious groups by denomination or some broader popular categorization, such as “fundamentalist” or “evangelical.” To capture religious differences more effectively, Steensland et al. (2000) propose an intricate classification of American denominations that takes into account the theology and historical development of various American religious traditions to predict individual attitudes and behaviors. We believe that equal care and attention should be devoted to the development of key measures of belief that may cross denominational lines. In this article, we propose one such measure: personal conceptions or …

The Evolution Of Human Life Expectancy And Intelligence In Hunter-Gatherer Economies, Hillard Kaplan

ESI Publications

The economics of hunting and gathering must have driven the biological evolution of human characteristics, since hunter-gatherer societies prevailed for the two million years of human history. These societies feature huge intergenerational resource flows, suggesting that these resource flows should replace fertility as the key demographic consideration. It is then theoretically expected that life expectancy and brain size would increase simultaneously, as apparently occurred during our evolutionary history. The brain here is considered as a direct form of bodily investment, but also crucially as facilitating further indirect investment by means of learning-by-doing.