Data for "Agency, Benevolence and Justice"
Prithvijit Mukherjee and J. Dustin Tracy
We test for social norms regarding how agents should select between risky prospects for principals, including norms consistent with beneficence and justice propositions from Adam Smith. We elicit norms from subjects serving as "impartial spectator[s]" about choice of risky prospect selected by the agents. We find strong evidence for the existence of norms, consistent with the Smith propositions. Furthermore we find that agents are more likely to select more normative options. In contrast, we find that principals' allocation for bonuses depends on the realization of the risky prospect rather than whether the agents choice was consistent with the norm.
Data for "Complements and Substitutes in a Dynamic Consumption-Asset Economy: A Laboratory Experiment"
David Porter, Benjamin Chase, Yijun Shen, and Vernon Smith
We examine a hybrid environment of the environments described above. In particular, we have an environment with current consumption (e.g., milk) and a corresponding asset market (e.g., goats) to store value over time. This environment is akin to a general equilibrium model in which one of the items traded is an asset.
Data for "Uncertainty and Reputation Effects in Credence Goods Markets"
Eric Schniter, J. Dustin Tracy, and Vojtěch Zíka
Credence-goods experiments have focused on stylized settings in which experts can perfectly identify the buyer’s best option and that option works without fail. However, in nature credence goods involve uncertainties that complicate assessing the quality of service and advice. We introduce two sources of uncertainty into a credence goods experiment. The first is diagnostic uncertainty; experts receive a noisy signal of buyer type so might make an ‘honest’ mistake when advising what is in buyers’ best interests. The second is service uncertainty; the services available to the buyer do not always work. Both sources of uncertainty make detection of expert dishonesty more difficult, so are expected to increase dishonesty by experts and decrease buyer trust (willingness to consult experts for advice and to follow expert advice) – decreasing efficiency of the interactions. We also analyze how buyers use ratings and whether ratings restrain both dishonesty and distrust by creating reliable reputations. In contrast to predictions, we find that uncertainty decreases dishonesty and increases trust. Also in contrast to predictions, ratings do not improve efficiency of the transactions under uncertainty – in part due to buyers’ tendency to ‘shoot the messenger’ (give low ratings) when they buy service that does not work due to bad luck, and to give experts the ‘benefit of the doubt’ (high ratings) when they buy service that may have been intentionally over-provided (not in the buyer’s best interest).
Data from: Mother's Social Status is Associated with Child Health in a Horticulturalist Population
Sarah Alami, Christopher von Rueden, Edmond Seabright, Thomas Kraft, Aaron Blackwell, Jonathan Stieglitz, Hillard Kaplan, and Michael Gurven
High social status is often associated with greater mating opportunities and fertility for men, but do women also obtain fitness benefits of high status? Greater resource access and child survivorship may be principal pathways through which social status increases women’s fitness. Here we examine whether peer-rankings of women’s social status (indicated by political influence, project leadership and respect) positively covaries with child nutritional status and health in a community of Amazonian horticulturalists. We find that maternal political influence, but not fathers’, is associated with improved child health outcomes in models adjusting for maternal age, parental height and weight, level of schooling, household income, family size, and number of co-resident kin in the community. Children of politically influential women have higher weight-for-age (B=0.33; 95% CI= 0.12 – 0.54), height-for-age (B=0.32; 95%CI=0.10 – 0.54), and weight-for-height (B= 0.24; 95% CI=0.04 – 0.44), and they are less likely to be diagnosed with common illnesses (OR= 0.48; 95% CI= 0.31 – 0.76). These results are consistent with women leveraging their social status to enhance reproductive success through improvements in child health. We discuss these results in light of parental investment theory and the implications for the evolution of female social status in humans.
Data from: Flexibility of Fetal Tolerance: Immune Function During Pregnancy Varies Between Ecologically Distinct Populations
Carmen Hové, Benjamin Trumble, Amy Anderson, Jonathan Stieglitz, Hillard Kaplan, Michael Gurven, and Aaron Blackwell
Background and objectives: Among placental mammals, females undergo immunological shifts during pregnancy to accommodate the fetus (i.e. fetal tolerance). Fetal tolerance has primarily been characterized within post-industrial populations experiencing evolutionarily novel conditions (e.g. reduced pathogen exposure), which may shape maternal response to fetal antigens. This study investigates how ecological conditions affect maternal immune status during pregnancy by comparing the direction and magnitude of immunological changes associated with each trimester among the Tsimane (a subsistence population subjected to high pathogen load) and women in the United States.
Methodology: Data from the Tsimane Health and Life History Project (N=935) and the National Health and Nutrition Examination Survey (N=1395) were used to estimate population-specific effects of trimester on differential leukocyte count and C-reactive protein (CRP), a marker of systemic inflammation.
Results: In both populations, pregnancy was associated with increased neutrophil prevalence, reduced lymphocyte and eosinophil count, and elevated CRP. Compared to their US counterparts, pregnant Tsimane women exhibited elevated lymphocyte and eosinophil counts, fewer neutrophils and monocytes, and lower CRP. Total leukocyte count remained high and unchanged among pregnant Tsimane women while pregnant US women exhibited substantially elevated counts, resulting in overlapping leukocyte prevalence among all third-trimester individuals.
Conclusions and implications: Our findings indicate that ecological conditions shape non-pregnant immune baselines and the magnitude of immunological shifts during pregnancy via developmental constraints and current trade-offs. Future research should investigate how such flexibility impacts maternal health and disease susceptibility, particularly the degree to which chronic pathogen exposure might dampen inflammatory response to fetal antigens.
Tsimane Physiological Dysregulation Data
Thomas Kraft, Jonathan Stieglitz, Benjamin Trumble, Angela Garcia, Hillard Kaplan, and Michael Gurven
Humans have the longest post-reproductive lifespans and lowest rates of actuarial aging among primates. Understanding the links between slow actuarial aging and physiological change is critical for improving the human “healthspan”. Physiological dysregulation may be a key feature of aging in industrialized populations with high burdens of chronic “diseases of civilization”, but little is known about age trajectories of physiological condition in subsistence populations with limited access to public health infrastructure. To better characterize human physiological dysregulation, we examined age trajectories of 40 biomarkers spanning the immune (n=13 biomarkers), cardiometabolic (n=14), musculoskeletal (n=6), and other (n=7) systems among Tsimane forager-horticulturalists of the Bolivian Amazon using mixed cross-sectional and longitudinal data (n=22,115 observations). We characterized age-related changes using a multi-system statistical index of physiological dysregulation (Mahalanobis distance; Dm) that increases with age in both humans and other primates. Although individual biomarkers showed varied age-profiles, we found a robust increase in age-related dysregulation for Tsimane (β=0.17-0.18) that was marginally faster than that reported for an industrialized Western sample (β=0.14-0.16), but slower than that of other non-human primates. We found minimal sex differences in the pace or average level of dysregulation for Tsimane. Our findings highlight some conserved patterns of physiological dysregulation in humans, consistent with the notion that somatic aging exhibits species-typical patterns, despite cross-cultural variation in environmental exposures, lifestyles and mortality.
Data for "An Experimental Investigation of Health Insurance Policy and Behavior"
J. Dustin Tracy, Hillard Kaplan, Kevin James, and Stephen Rassenti
We introduce a new experimental approach to measuring the effects of health insurance policy alternatives on behavior and health outcomes over the life course. Cash-motivated subjects are placed in a virtual environment where they earn income and allocate it across multi-period lives. We compare behavior across age, income and insurance plans---one priced according to an individual's expected cost and the other uniformly priced through employer-implemented cost sharing. We find that 1) subjects in the employer-implemented plan purchased insurance at higher rates; 2) the employer-based plan reduced differences due to income and age; 3) subjects in the actuarial plan engaged in more health-promoting behaviors, but still below optimal levels, and did save at the level required, so did realize the full benefits of the plan. Subjects had more difficulty optimizing choices in the Actuarial treatment, because it required more long- term planning and evaluating benefits that compounded over time. Contrary, to model predictions, the actuarial priced insurance plan did not increase utility relative to the employer-based plan.
Data for "Consistent Differences in a Virtual World Model of Ape Societies"
Bart J. Wilson, Sarah F. Brosnan, Elizabeth V. Lonsdorf, and Crickette M. Sanz
The zip file contains the data for the paper entitled "Consistent Differences in a Virtual World Model of Ape Societies" which appears in Scientific Reports.
Data from: Computed Tomography Shows High Fracture Prevalence Among Physically Active Forager-Horticulturalists with High Fertility
Jonathan Stieglitz, Benjamin Trumble, HORUS Study Team, Caleb Finch, Dong Li, Matthew J. Budoff, Hillard Kaplan, and Michael Gurven
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 easily explain Tsimane women's lower BMD. Tsimane fracture prevalence is also higher versus Americans. Lower BMD increases Tsimane fracture risk, but only for women, suggesting a role of weak bone in women's fracture etiology. Our results highlight the role of sex-specific mechanisms underlying skeletal fragility that operate long before menopause.
Data from: Deliberation Favours Social Efficiency by Making People Disregard Their Relative Shares: Evidence from USA and India
Valerie Capraro, Brice Corgnet, Antonio M. Espín, and Roberto Hernán-González
Groups make decisions on both the production and the distribution of resources. These decisions typically involve a tension between increasing the total level of group resources (i.e. social efficiency) and distributing these resources among group members (i.e. individuals' relative shares). This is the case because the redistribution process may destroy part of the resources, thus resulting in socially inefficient allocations. Here we apply a dual-process approach to understand the cognitive underpinnings of this fundamental tension. We conducted a set of experiments to examine the extent to which different allocation decisions respond to intuition or deliberation. In a newly developed approach, we assess intuition and deliberation at both the trait level (using the Cognitive Reflection Test, henceforth CRT) and the state level (through the experimental manipulation of response times). To test for robustness, experiments were conducted in two countries: the USA and India. Despite absolute-level differences across countries, in both locations we show that: (i) time pressure and low CRT scores are associated with individuals' concerns for their relative shares and (ii) time delay and high CRT scores are associated with individuals' concerns for social efficiency. These findings demonstrate that deliberation favours social efficiency by overriding individuals' intuitive tendency to focus on relative shares.
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