Other Economics Commons^™

More Than The Sum Of Its Sexes: Functional Constraints, Embodied Capital, And Age-Structured Labor In Human Forager Economies, Eric Schniter, Hillard Kaplan, Brenda Bowser, Cari Goetz

ESI Publications

"The paper's rough consensus attributes the SDoL to differential variance in food returns across male- and female-typical foraging domains, sourcing this primarily to Bird and Codding (2015) and Kelly's (2013) reframe of the classic 'hunting vs. gathering' axis as 'risky vs. non-risky foraging.' Indeed, the data show that males more often pursue large game and honey, resources that yield higher caloric returns but with high unpredictability, injury risk, and failure rates. Females, especially those with dependent young, more often target plant foods and small game that produce steadier, lower-variance returns. But variance-buffering is a proximate ecological account, not a life …

Segmentation And Morphometry Of Intracranial Internal Carotid Artery Calcification In Relation To Brain Atrophy, Xiao Xu, Nikhil N. Chaudhari, Phoebe E. Imms, Nahian F. Chowdhury, Fangyun C. Liu, Jorge A. Solis Galvan, Bavrina Bigjahan, Grant Schleifer, Maria Ashna, Blake Hannagan, Giuseppe Barisano, Daniel K. Cummings, Daniel Eid Rodriguez, Paul L. Hooper, Edmond Seabright, Randall C. Thompson, Benjamin C. Trumble, Michael D. Gurven, Jonathan Stieglitz, Caleb E. Finch, M. Linda Sutherland, James D. Sutherland, Helena C. Chui, Margaret Gatz, Wendy J. Mack, Hillard Kaplan, Andrei Irimia

ESI Publications

Purpose

Intracranial internal carotid artery calcification (iICAC) is a form of intracranial arteriosclerosis and is associated with an elevated risk of stroke and dementia. However, iICAC’s relationship with brain atrophy remains poorly understood. We aimed to automatically quantify iICAC morphometric characteristics and evaluate their associations with regional brain volumes (BVs).

Methods

We developed an automated approach to compute iICAC surface area and thickness from CT brain scans in a sample of physically active South American subsistence farmers (n = 1,232, age range: 40 years to 92 years, 48.1% female, 794 Tsimane and 438 Moseten). Linear regression models were used …

High Prevalence Of Cerebrovascular Calcifications And Clinical Correlates In Indigenous Bolivian Forager‐Horticulturalists: A Population‐Based Observational Study, Giuseppe Barisano, Bavrina Bigjahan, Grant Schleifer, Maria Ashna, Wendy J. Mack, M. Linda Sutherland, James D. Sutherland, Helena C. Chui, Meng Law, Thomas J. Fischbach, Andrei Irimia, Nikhil N. Chaudhari, Daniel K. Cummings, Paul L. Hooper, Jacob E. Aronoff, Ellen E. Walters, Daniel Eid Rodriguez, Raul Quispe Gutierrez, Jesus Bani Cuata, Kenneth Buetow, Caleb E. Finch, Michael D. Gurven, Jonathan Stieglitz, Gregory S. Thomas, Randall C. Thompson, Benjamin Trumble, Hillard Kaplan, Margaret Gatz

ESI Publications

Background

Methods

For Whom Do Labels Work? Heterogeneous Effects Of Popularity And Environmental Information In Coffee Choice, Dede Long, Joaquín Gómez-Miñambres, Hongxing Liu

ESI Publications

We examine the impact of two common food labels on consumers’ choices: environmental certification and popularity cues. In a randomized experiment, participants chose between two similar coffee products, with treatments varying the presence of environmental and/or popularity information. We also collected measures of conformity preferences, environmental concern, political identity, and demographics. At the aggregate level, the environmental and combined labels significantly increased the selection of the target coffee, whereas popularity information alone had no effect. These averages conceal substantial heterogeneity: high-conformity participants responded to all labels, especially popularity cues, while those with domain-specific environmental concerns responded only to environmental and …

Oxytocin Varies Across The Life Course In A Sex-Specific Way In A Human Subsistence Population, Abigail E. Colby, Dominik C. Jud, Valerie Baettig, Jordan S. Martin, Camila Scaff, Michael D. Gurven, Benjamin C. Trumble, Bret A. Beheim, Paul L. Hooper, Daniel K. Cummings, Hillard Kaplan, Jonathan Stieglitz, Arnulfo Cary Ista, Adrian V. Jaeggi

ESI Publications

Oxytocin, a hormone linked to reproduction and health, may mediate life-history trade-offs across the human life course. Yet, how oxytocin naturally varies with age remains poorly understood. Here, working with the Tsimane, forager-horticulturalists of lowland Bolivia, we collected the largest sample of oxytocin measurements to date (n = 1,242 samples, n = 405 individuals, age = 2 to 84 y, 51% female), and i) examined how oxytocin varies throughout the life course in females and males, and ii) investigated potential drivers of age- and sex-specific variation. Our sample provides rare insight into the relationship between oxytocin and age in a …

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 …

The Discouraging Effect Of Overconfidence, Cary Deck, Klajdi Bregu

ESI Publications

Overconfidence is often viewed as encouraging entrepreneurs and CEOs to follow risky strategies such as entering new markets, engaging in innovation, or pursuing mergers and acquisitions. While such undertakings can generate excess returns and profits, overconfidence is frequently offered as an explanation for why so many business ventures fail. However, we show that in a setting where the decision maker does not know whether success is possible, theoretically, overconfidence can also have a discouraging effect, causing one to give up too soon. This counterintuitive result is driven by effectively misattributing one's own failure to an elevated assessment of the chance …

Ectopic Adipose Tissue In Subsistence Populations With Minimal Coronary Disease, Large Left Atria, And Very Low Rates Of Atrial Fibrillation, Randall C. Thompson, Benjamin C. Trumble, Daniel K. Cummings, Angela D. Neunuebel, Paul L. Hooper, Samuel Wann, Adel H. Allam, Frances Neunuebel, Benjamin D. Gans, Samantha I. King, Edmond Seabright, Caleb E. Finch, Margaret Gatz, Kenneth Buetow, Michael I. Miyamoto, Guido P. Lombardi, M. Linda Sutherland, James D. Sutherland, Christopher J. Ward, Madeleine J. Lee, Ashna Mahadev, Daniel Eid Rodriguez, David E. Michalik, Chris J. Rowan, Tianyu Cao, Jonathan Stieglitz, Cameron M. Quick, Gregory S. Thomas, Jagat Narula, Damini Dey, Michael Gurven, Hillard Kaplan

ESI Publications

Background

Methods

Indirect Genetic Effects Among Neighbors Promote Cooperation And Accelerate Adaptation In A Small-Scale Human Society, Jordan S. Martin, Bret Beheim, Michael Gurven, Hillard Kaplan, Jonathan Stieglitz, Benjamin C. Trumble, Paul Hooper, Daniel K. Cummings, Daniel Eid Rodriguez, Adrian V. Jaeggi

ESI Publications

Explaining the rapid evolution of human cooperation and its role in our species’ biodemographic success remains a major evolutionary puzzle. To address this challenge, we tested a social drive hypothesis, which predicts that social plasticity and social selection in human groups cause indirect genetic effects that accelerate the adaptation of fitness, promoting population growth via feedback between the environmental causes and evolutionary consequences of cooperation. Using Bayesian multilevel models to analyze fertility data from a small-scale society, we demonstrate that density- and frequency-dependent indirect genetic effects on fitness promote the evolution of cooperation among neighboring women, increasing the rate of …

Physical Activity Mediates Age Differences In Cognition Among Tsimane Forager-Horticulturalists, Phoebe E. Imms, Nikhil N. Chaudhari, Daniel Cummings, Daniel Eid Rodriguez, Giuseppe Barisano, Paul L. Hooper, M. Katherine Sayre, Edmond Seabright, Randall C. Thompson, M. Linda Sutherland, James D. Sutherland, Benjamin C. Trumble, Michael Gurven, Jonathan Stieglitz, Caleb E. Finch, Hillard S. Kaplan, Wendy J. Mack, Margaret Gatz, Andrei Irimia

ESI Publications

Background: The Tsimane and Moseten of the Bolivian Amazon are highly physically active and exhibit low rates of cognitive impairment and brain atrophy.

Methods: We use structural equation modelling to examine how their physical activity levels mediate the relationship between (1) age and cognition, and (2) age and cognition via brain volume (BV).

Results: Tsimane males (n = 305, mean ± SD age = 59.94 ± 9.68) and Tsimane females (n = 265, mean ± SD age = 59.28 ± 9.79) exhibit significantly higher levels of physical activity than Moseten males (n = 106, mean ± SD …

Higher Blood Lipid Levels After The Transition To Menopause In Two Forager-Horticulturalist Populations, M. J. Getz, J. E. Aronoff, C. L. Jenkins, S. Ghafoor, J. Vazquez, N. T. Appel, M. Gatz, Daniel K. Cummings, Paul L. Hooper, B. Beheim, K. H. Buetow, C. E. Finch, G. S. Thomas, J. Stieglitz, M. Gurven, Hillard Kaplan, B. C. Trumble

ESI Publications

Background: Reproduction affects health and longevity among females across the life course. While significant focus has been devoted to the role of menarche, menopause remains understudied. Most menopause research is conducted in industrialized populations, where the risk of cardiovascular diseases increases progressively during the menopausal transition.

Methodology: Weworked with the Tsimane, Indigenous Bolivian forager-farmers with physically active lifestyles, and the Moseten, genetically and culturally related horticulturalists experiencing greater market integration. We assessed relationships between menopause status and lipid biomarkers (HDL, LDL, non-HDL, total cholesterol, triglycerides, and apolipoprotein-B). Using linear mixed-effects models, in an all-age sample of n = …

Childhood Skeletal Lesions Common In Prehistory Are Present In Living Forager-Farmers And Predict Adult Markers Of Immune Function, Amy S. Anderson, Aaron Blackwell, M. Linda Sutherland, Thomas Kraft, James Sutherland, Bret Beheim, Daniel K. Cummings, Suhail Ghafoor, Paul L. Hooper, Daniel Eid Rodriguez, Andrei Irimia, Margaret Gatz, Wendy Mack, Chris Rowan, Michael Miyamoto, Kenneth Buetow, Caleb Finch, L. Samuel Wann, Adel Allam, Randall C. Thompson, Gregory Thomas, Hillard Kaplan, Jonathan Stieglitz, Benjamin Trumble, Michael D. Gurven

ESI Publications

Porous cranial lesions (cribra cranii and cribra orbitalia) are widely used by archaeologists as skeletal markers of poor child health. However, their use has not been validated with systematic data from contemporary populations, where there has been little evidence of these lesions or their health relevance. Using 375 in vivo computed tomography scans from a cohort-representative sample of adults aged 40+ years from the Bolivian Amazon, among food-limited, high-mortality forager-farmers, we identified cribra cranii on 46 (12.3%) and cribra orbitalia on 23 (6%). Cribra orbitalia was associated with several hallmarks of compromised immune function, including fewer B cells, fewer naïve …

Arterial Stiffness In Heart-Healthy Indigenous Tsimane Forager-Horticulturalists, Tianyu Cao, Edhitt Cortez Linares, Raul Quispe Gutierrez, Daniel Eid Rodriguez, Jesus Bani Cuata, Michael I. Miyamoto, Christopher Von Rueden, Daniel K. Cummings, Paul L. Hooper, Benjamin C. Trumble, Jonathan Stieglitz, Randall C. Thompson, Gregory S. Thomas, Hillard S. Kaplan, Daniel A. Duprez, David R. Jacobs Jr., Michael Gurven

ESI Publications

Background

Methods

Energy Expenditure And Obesity Across The Economic Spectrum, Amanda Mcgrosky, Amy Luke, Leonore Arab, Kweku Bedu-Addo, Alberto G. Bonomi, Pascal Bovet, Soren Brage, Maciej S. Buchowski, Nancy Butte, Stefan G. Camps, Regina Casper, Daniel K. Cummings, Sai Krupa Das, Sanjoy Deb, Lara R. Dugas, Ulf Ekelund, Terrence Forrester, Barry W. Fudge, Melanie Gillingham, Annelies H. Goris, Michael Gurven, Catherine Hambly, Annemiek Joosen, Peter T. Katzmarzyk, Kitty P. Kempen, William E. Kraus, Wantanee Kriengsinyos, Rebecca Kuriyan, Robert F. Kushner, Estelle V. Lambert, Christel L. Larsson, William R. Leonard, Nader Lessan, Marie Löf, Corby K. Martin, Anine C. Medin, Marian L. Neuhouser, Kirsi H. Pietilainen, Guy Plasqui, Ross L. Prentice, Susan B. Racette, David A. Raichlen, Eric Ravussin, Leanne Redman, Rebecca M. Reynolds, Eric B. Rimm, Susan Roberts, Asher Y. Rosinger, Mary H. Samuels, Srishti Sinha, J. Josh Snodgrass, Eric Stice, Ricardo Uauy, Samuel S. Urlacher, Jeanine A. Verbunt, Bruce Wolfe, Brian Wood, Xueying Zhang, Alexia J. Murphy-Alford, Cornelia J. Loechl, Jennifer Rood, Hiroyuki Sagayama, Dale A. Schoeller, Klaas R. Westerterp, William W. Wong, Yosuke Yamada, John R. Speakman, Herman Pontzer, The Iaea Dlw Database Consortium

ESI Publications

Global economic development has been associated with an increased prevalence of obesity and related health problems. Increased caloric intake and reduced energy expenditure are both cited as development-related contributors to the obesity crisis, but their relative importance remains unresolved. Here, we examine energy expenditure and two measures of obesity (body fat percentage and body mass index, BMI) for 4,213 adults from 34 populations across six continents and a wide range of lifestyles and economies, including hunter-gatherer, pastoralist, farming, and industrialized populations. Economic development was positively associated with greater body mass, BMI, and body fat, but also with greater total, basal, …

The Impact Of Insufficient Sleep On Dietary Choices And Physical Activity Behaviors: Evidence From A Randomized Cross-Over Trial, David L. Dickinson, Naomi Kakoschke, Sean P. A. Drummond

ESI Publications

The current study aimed to identify how manipulated sleep restriction affects dietary choices and physical activity (PA). Young adults were administered one week of well-rested sleep levels (WR: 8–9 h/night) and sleep-restriction (SR: 5–6 h/night) in their (naturalistic) at-home setting, using a randomized cross-over design. Participants made consequential bids for snacks/beverages following SR and WR in an auction task. Other primary outcome measures included daily self-reported dietary intake and actigraphy-measured PA. Multivariate regression analyses examined main and moderator impacts of SR on primary outcome measures. In total, 118 treatment participants completed the study (M = 20 years old, n = …

The Effects Of Sleep Restriction And Time Of Day On Food-Specific Impulsivity, Approach-Avoidance Bias And Delay Discounting, Naomi Kakoschke, David L. Dickinson, Sean P. A. Drummond

ESI Publications

Background:

Insufficient sleep and circadian timing are both linked with obesity, primarily via unhealthy food choice, yet the cognitive mechanisms underpinning such relationships remain unclear.

Methods:

Across two studies, we implemented an ecologically valid within-subjects at-home protocol. Study 1 (n = 118) involved a within-subjects examination of how sleep restriction (SR) versus well-rested (WR) sleep levels affect choices in a food-based approach-avoidance task (AAT) and go–no/go (GNG) task, a food liking task, a food-choice task, a psychomotor vigilance task (PVT), and a monetary choice task. Study 2 (n = 119) involved examining choices in the same set of …

Adam Smith’S Modeling Of Agents: Roots Versus Consequences Of Action, Vernon L. Smith, Sabiou M. Inoua

ESI Publications

Adam Smith founded his investigations of economic and social exchanges on the roots of human action (sympathy, need, self-interest), unlike the utilitarians (Hume and the neoclassical economists), who centered theirs on the consequences of human action (pleasure, utility of outcome). This distinction is key to understanding the contrast between the two schools of thought, as we emphasize in this chapter.

Cost-Effective Solutions For High-Throughput Enzymatic Dna Methylation Sequencing, Amy Longtin, Marina M. Watowich, Baptiste Sadoughi, Rachel M. Petersen, Sarah F. Brosnan, Kenneth Buetow, Qiuyin Cai, Cayo Biobank Research Unit, Vanderbilt University, Michael D. Gurven, James P. Higham, Heather M. Highland, Yi-Ting Huang, Hillard Kaplan, Thomas S. Kraft, Yvonne A. L. Lim, Jirong Long, Amanda D. Melin, Michael J. Montagne, Jamie Roberson, Kee Seong Ng, Michael L. Platt, India A. Schneider-Crease, Jonathan Stieglitz, Benjamin C. Trumble, Vivek Venkataraman, Ian J. Wallace, Jie Wu, Noah Snyder-Mackler, Angela Jones, Alexander G. Bick, Amanda J. Lea

ESI Publications

Characterizing DNA methylation patterns is important for addressing key questions in evolutionary biology, development, geroscience, and medical genomics. While costs are decreasing, whole-genome DNA methylation profiling remains prohibitively expensive for most population-scale studies, creating a need for cost-effective, reduced representation approaches (i.e., assays that rely on microarrays, enzyme digests, or sequence capture to target a subset of the genome). Most common whole genome and reduced representation techniques rely on bisulfite conversion, which can damage DNA resulting in DNA loss and sequencing biases. Enzymatic methyl sequencing (EM-seq) was recently proposed to overcome these issues, but thorough benchmarking of EM-seq combined with …

Moral Preferences In Ultimatum And Impunity Games, Valerie Capraro, Ismael Rodriguez-Lara

ESI Publications

We report on two experiments (total N = 2572) testing the role of moral preferences in one-shot, anonymous ultimatum and impunity games, which vary the veto power of responders. In the impunity game, if an offer is lower than the responder’s minimum acceptable offer, the proposer still receives his share, while the responder gets nothing. Study 1 is correlational and explores how moral preferences, as measured using the Moral Foundations Questionnaire, explain behaviour in the two games. Study 2 is causal and investigates the effect of moral suasion on behaviour. Regarding proposers, both studies provide evidence that moral preferences affect …

The Impact Of Insufficient Sleep On The Serial Reproduction Of Information, David L. Dickinson, Sean P. A. Drummond

ESI Publications

Story retelling is an important form of communication, cultural practice, and message transmission. Insufficient sleep is known to affect relevant cognitive skill areas necessary for story retelling or transmission fidelity. We conducted a preregistered randomized cross-over study on n = 155 young adults with exogenously assigned nightly sleep levels experienced in their at-home environments. A serial story reproduction task was administered online, and chains of up to three retells of a given story involved varied numbers of sleep restricted (SR) versus well-rested (WR) retellers. While story content decayed with each retell, group-level analysis showed that additional SR retellers in a …

Ruchir Sharma: What Went Wrong With Capitalism, Vernon L. Smith

ESI Publications

A review of Ruchir Sharma's What Went Wrong With Capitalism.

When The Rich Do (Not) Trust The (Newly) Rich: Experimental Evidence On The Effects Of Positive Random Shocks In The Trust Game, Hernán Bejarano, Joris Gillet, Ismael Rodriguez-Lara

ESI Publications

We study behavior in a trust game where first-movers initially have a higher endowment than second-movers but the occurrence of a positive random shock can eliminate this inequality by increasing the endowment of the second-mover before the decision of the first-mover. We find that second-movers return less (i.e., they are less trustworthy) when they have a lower endowment than first-movers, compared with the case in which first and second-movers have the same endowment. In addition, second-movers who experience the positive shock return more than second-movers who have the same endowment as the first-mover from the outset. First-movers do not seem …

From Shocks To Solidarity And Superstition: Exploring The Foundations Of Faith, Aidin Hajikhameneh, Laurence R. Iannaccone

ESI Publications

Additive shocks can substantially increase cooperation in otherwise standard public goods game experiments. We study shocks that randomly adjust players’ earnings by a fixed positive or negative amount reported at the end of each round. These adjustments change neither the return to players’ contributions nor the information about other group members. We compare results across four treatments that employ the same group-level adjustment algorithm but frame it differently, with pre-play descriptions that range from omitting all useful information to accurately revealing its 50/50 random nature. In each treatment, overall contributions run about 50% higher than those obtained in the standard …

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 = …

Political Ideology, Emotion Response, And Confirmation Bias, David L. Dickinson

ESI Publications

Motivated reasoning can serve to help resolve emotional discomfort, which suggests emotion as a likely moderator of such reasoning. This paper addresses a gap in the literature by examining emotion and confirmation bias in the political domain. Results from two preregistered studies, which involved over 900 unique participants, document a confirmation bias across distinct dimensions of belief and preference formation. Also, ideologically dissonant information significantly worsens self-reported emotion. With some exceptions, the evidence generally supports the hypothesis that negative emotion moderates the strength of the bias, which highlights the importance of emotion response in understanding and potentially counteracting confirmation bias.

Adam Smith, Human Betterment, And His Erroneous Indentification With Self-Interested Human Action, Vernon L. Smith

ESI Publications

In this essay I discuss the proposition that Adam Smith has been widely misinterpreted as asserting in his second book, The Wealth of Nations, that emergent modern economies are driven by the strictly selfish motives of their human inhabitants. The propositions articulated in his first book, The Theory of Moral Sentiments, which offered a theory of society, extended seamlessly into his second book, and continued to be part of his theory of economy. In both works, he distinguished the universal state of being self-interested from actions taken in one's self-interest, and modeled people as creating and following rules of propriety …

Gambling Habits And Probability Judgements In A Bayesian Task Environment, David L. Dickinson, Parker Reid

ESI Publications

Little is known about how gamblers form probability assessments. This paper reports on a preregistered study that administered an incentivized Bayesian choice task to n = 465 self-reported gamblers and non-gamblers. The task elicits subjective probability assessments and allows one to estimate the degree to which distinct information sources are weighted in forming probability assessments. Our data failed to support our main hypotheses that experienced online gamblers would be more accurate than non-gamblers in estimating probabilities, that gamblers experienced in games of skill (e.g., poker) would be more accurate than gamblers experienced only in non-skill games (e.g., slots), that accuracy …

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 …

Cross-Cousin Marriage Among Tsimane Forager–Horticulturalists During Demographic Transition And Market Integration, Arianna Dalzero, Bret A. Beheim, Hillard Kaplan, Jonathan Stieglitz, Paul L. Hooper, Cody T. Ross, Michael D. Gurven, Dieter Lukas

ESI Publications

Although still prevalent in many human societies, the practice of cousin marriage has precipitously declined in populations undergoing rapid demographic and socioeconomic change. However, it is still unclear whether changes in the structure of the marriage pool or changes in the fitness-relevant consequences of cousin marriage more strongly influence the frequency of cousin marriage. Here, we use genealogical data collected by the Tsimane Health and Life History Project to show that there is a small but measurable decline in the frequency of first cross-cousin marriage since the mid-twentieth century. Such changes are linked to concomitant changes in the pool of …

Coordinated And Uncoordinated Punishment In A Team Investment Game, Vicente Calabuig, Natalia Jiménez-Jiménez, Gonzalo Olcina, Ismael Rodriguez-Lara

ESI Publications

Coordinated punishment occurs when punishment requires a specific number of punishers to be effective, otherwise, no damage will be inflicted on the target. While societies often rely on this punishment device, its benefits are unclear compared to uncoordinated punishment, where punishment decisions are substitutes. In this paper, we compare the efficacy of coordinated and uncoordinated punishment in a team investment game with two investors and one allocator. Our findings indicate that coordinated punishment results in higher levels of cooperation and reciprocity, as measured by the levels of joint investment and the return by allocators. Importantly, this does not translate into …