Explanipedia

Sources of Fitness Interdependence Associated with Shared Fate and Cooperation in a Small-scale Horticultural Society Open

Diego Guevara Beltrán, Jessica D. Ayers, Lee Cronk, Daniel Balliet, Jeremy Koster , et al. · 2025

Cooperation often relies on people’s ability to discern in whom to invest their limited resources. One solution to this partner choice dilemma entails estimating one’s fitness interdependence with others. Previous studies indicate that est…

Reproductive inequality in humans and other mammals Open

Cody T. Ross, Paul L. Hooper, Jennifer E. Smith, Adrian V. Jaeggi, Eric Alden Smith , et al. · 2025

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…

Is gender primacy universal? Open

Ashley E. Martin, Diego Guevara Beltrán, Jeremy Koster, Jessica L. Tracy · 2024

Emerging evidence suggests that gender is a defining feature of personhood. Studies show that gender is the primary social category individuals use to perceive humanness and the social category most strongly related to seeing someone—or so…

Evidence of direct and indirect reciprocity in network-structured economic games Open

Daniel Redhead, Matthew M. Gervais, Kotrina Kajokaite, Jeremy Koster, Arlenys Hurtado Manyoma , et al. · 2024

Formal theoretical models propose that cooperative networks can be maintained when individuals condition behavior on social standing. Here, we empirically examine the predictions of such models of positive and negative indirect reciprocity…

Women’s subsistence strategies predict fertility across cultures, but context matters Open

Abigail E. Page, Erik J. Ringen, Jeremy Koster, Monique Borgerhoff Mulder, Karen L. Kramer , et al. · 2024

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities—incorporati…

Effects of Voice Pitch on Social Perceptions Vary With Relational Mobility and Homicide Rate Open

Toe Aung, Alexander K. Hill, Jessica K. Hlay, Catherine Hess, Michael Heß , et al. · 2024

Fundamental frequency ( f o ) is the most perceptually salient vocal acoustic parameter, yet little is known about how its perceptual influence varies across societies. We examined how f o affects key social perceptions and how socioecolog…

Child and adolescent foraging: New directions in evolutionary research Open

Ilaria Pretelli, Alyssa N. Crittenden, Edmond Dounias, Sagan Friant, Jeremy Koster , et al. · 2024

Young children and adolescents in subsistence societies forage for a wide range of resources. They often target child‐specific foods, they can be very successful foragers, and they share their produce widely within and outside of their nuc…

Child and Adolescent Foraging: New Directions in Evolutionary Research Open

Ilaria Pretelli, Alyssa N. Crittenden, Edmond Dounias, Sagan Friant, Jeremy Koster , et al. · 2023

Young children and adolescents in subsistence societies forage for a wide range of resources. They often target child-specific foods, they can be very successful foragers, and they share their produce widely within and outside of their nuc…

Nonverbal displays of dominance and prestige: Evidence for cross-cultural and early-emerging recognition Open

Zachary Witkower, Alexander K. Hill, Anthea Pun, Andrew Scott Baron, Jeremy Koster , et al. · 2023

Two universal strategies for attaining influence – dominance, or the use of intimidation and force to obtain power, and prestige, or garnering respect by demonstrating knowledge and expertise – are communicated through distinct nonverbal d…

Reproductive inequality in humans and other mammals Open

Cody T. Ross, Paul L. Hooper, Jennifer E. Smith, Adrian V. Jaeggi, Eric Alden Smith , et al. · 2023

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…

Latent network models to account for noisy, multiply reported social network data Open

Caterina De Bacco, Martina Contisciani, Jonathan Cardoso‐Silva, Hadiseh Safdari, Gabriela Lima Borges , et al. · 2023

Social network data are often constructed by incorporating reports from multiple individuals. However, it is not obvious how to reconcile discordant responses from individuals. There may be particular risks with multiply reported data if p…

Socioecology shapes child and adolescent time allocation in twelve hunter-gatherer and mixed-subsistence forager societies Open

Sheina Lew‐Levy, Rachel Reckin, Stephen M. Kissler, Ilaria Pretelli, Adam H. Boyette , et al. · 2022

Social integration predicts survival in female white-faced capuchin monkeys Open

Kotrina Kajokaite, Andrew Whalen, Jeremy Koster, Susan Perry · 2022

Across multiple species of social mammals, a growing number of studies have found that individual sociality is associated with survival. In long-lived species, like primates, lifespan is one of the main components of fitness. We used 18 ye…

Is a downwards head tilt a cross-cultural signal of dominance? Evidence for a universal visual illusion Open

Zachary Witkower, Alexander K. Hill, Jeremy Koster, Jessica L. Tracy · 2022

The present pre-registered research provides the first evidence that a downwards head tilt is sufficient to communicate dominance from a neutral facial expression among the Mayangna, members of an unindustrialized, small-scale traditional …

Latent Network Models to Account for Noisy, Multiply-Reported Social Network Data Open

Caterina De Bacco, Martina Contisciani, Jonathan Cardoso‐Silva, Hadiseh Safdari, Diego Baptista , et al. · 2021

Social network data are often constructed by incorporating reports from multiple individuals. However, it is not obvious how to reconcile discordant responses from individuals. There may be particular risks with multiply-reported data if p…

Does Wealth Predict Health Among Dogs in a Protected Area? Open

Eric Eisenman, Jeremy Koster, Janet E. Foley, Christine V. Fiorello · 2021

As the world's most ubiquitous carnivore, domestic dogs maintain unique proximity to human populations. Partly because dogs potentially serve as hosts of zoonotic diseases, determinants of canine health are increasingly the focus of interd…

Socioecology shapes child and adolescent time allocation in twelve hunter-gatherer and mixed-subsistence forager societies Open

Sheina Lew‐Levy, Rachel Reckin, Stephen M. Kissler, Ilaria Pretelli, Adam H. Boyette , et al. · 2021

A key issue distinguishing prominent evolutionary models of human life history is whether prolonged childhood evolved to facilitate learning in a skill- and strength-intensive foraging niche requiring high levels of cooperation. Considerin…

Beyond Face Value: Evidence for the Universality of Bodily Expressions of Emotion Open

Zachary Witkower, Alexander K. Hill, Jeremy Koster, Jessica L. Tracy · 2021

Timing, Initiators, and Causes of Divorce in a Mayangna/Miskito Community in Nicaragua Open

Jeffrey Winking, Jeremy Koster · 2021

There exists a paucity of evolution-oriented research focusing on why relationships end, particularly in comparison to the substantial literature centered around individual preferences that define the beginning of relationships. In contras…

Biology’s best friend: Bridging disciplinary gaps to advance canine science Open

Caleb M. Bryce, Michael S. Davis, Matthew E. Gompper, Aimee Hurt, Jeremy Koster , et al. · 2021

The rich history and global abundance of domestic dogs (Canis familiaris) present a unique opportunity and an ideal model for interdisciplinary research. Canine evolutionary history demonstrates unprecedented changes across all levels of b…

Most Dogs Are Not NATIVE Dogs Open

Jeremy Koster · 2021

Studies of dogs have proliferated among canine scientists, aided in part by the logistical convenience of working with owned animals whose care is handled by others. These pet dogs are unlike most dogs that have lived in contemporary or pr…

Small-scale utilitarianism: High acceptance of utilitarian solutions to Trolley Problems among a horticultural population in Nicaragua Open

Jeffrey Winking, Jeremy Koster · 2021

Researchers often use moral dilemmas to investigate the specific factors that influence participants’ judgments of the appropriateness of different actions. A common construction of such a dilemma is the Trolley Problem, which pits an obvi…

Fur Color and Nutritional Status Predict Hair Cortisol Concentrations of Dogs in Nicaragua Open

Grace B. Bowland, Robin M. Bernstein, Jeremy Koster, Christine V. Fiorello, Maris Brenn‐White , et al. · 2020

This study examined the relationships between hair cortisol concentrations (HCC) and sex, age, nutritional status (as determined by body condition scores, or BCS), and body mass (geometric mean calculated from morphometric measurements), a…

Social integration predicts survival in female white-faced capuchin monkeys Open

Kotrina Kajokaite, Andrew Whalen, Jeremy Koster, Susan Perry · 2020

Across multiple species of social mammals, a growing number of studies have found that that individual sociality is associated with survival. In long-lived species, like primates, lifespan is one of the main components of fitness. We used …

The life history of human foraging: Cross-cultural and individual variation Open

Jeremy Koster, Richard McElreath, Kim Hill, Douglas W. Yu, Glenn H. Shepard , et al. · 2020

Hunters exhibit high skill across the life span, individuals vary substantially in skill, and age-related peaks vary across sites.

Dyadic Reciprocity as a Function of Covariates Open

Jeremy Koster · 2020

Reciprocity in dyadic interactions is common and a topic of interest across disciplines. In some cases, reciprocity may be expected to be more or less prevalent among certain kinds of dyads. In response to interest among researchers in est…

Small-Scale Utilitarianism: High Acceptance of Utilitarian Solutions to Trolley Problems among a Horticultural Population Open

Jeffrey Winking, Jeremy Koster · 2020

The study of moral dilemmas enables researchers to investigate the specific factors that influence humans’ judgments of the appropriateness of different actions. A common construction of this dilemma is the so-called Trolley Problem, which…

Methods and Software for the Multilevel Social Relations Model: A Tutorial Open

Jeremy Koster, George Leckie, Brandy Aven, Christopher M J Charlton · 2019

This tutorial demonstrates the estimation and interpretation of the Multilevel Social Relations Model for dyadic data. The Social Relations Model is appropriate for data structures in which individuals appear multiple times as both the sou…

Patterns of paternal investment predict cross-cultural variation in jealous response Open

Brooke A. Scelza, Sean P. Prall, Tami Blumenfield, Alyssa N. Crittenden, Michael Gurven , et al. · 2019

Kinship ties across the lifespan in human communities Open

Jeremy Koster, Dieter Lukas, David A. Nolin, Eleanor A. Power, Alexandra Alvergne , et al. · 2019

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-generation…

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