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Engagement in agricultural work is associated with reduced leisure time among Agta hunter-gatherers

DOI:10.1038/s41562-019-0614-6
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Mark Dyble at University College London
Mark Dyble
Jack Thorley at University of Liverpoool
Jack Thorley
  • University of Liverpoool
Abigail E Page at London School of Hygiene and Tropical Medicine
Abigail E Page
Daniel Smith at University of Bristol
Daniel Smith
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A long-standing hypothesis suggests that the transition from hunting and gathering to agriculture results in people working harder, spending more time engaged in subsistence activities and having less leisure time1,2. However, tests of this hypothesis are obscured by comparing between populations that vary in ecology and social organization, as well as subsistence3–6. Here we test this hypothesis by examining adult time allocation among the Agta—a population of small-scale hunter-gatherers from the northern Philippines who are increasingly engaged in agriculture and other non-foraging work. We find that individuals in camps engaging more in non-foraging work spend more time involved in out-of-camp work and have substantially less leisure time. This difference is largely driven by changes in the time allocation of women, who spend substantially more time engaged in out-of-camp work in more agricultural camps. Our results support the hypothesis that hunting and gathering allows a significant amount of leisure time, and that this is lost as communities adopt small-scale agriculture.
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https://doi.org/10.1038/s41562-019-0614-6
1Jesus College, University of Cambridge, Cambridge, UK. 2Department of Zoology, University of Cambridge, Cambridge, UK. 3Department of Population
Health, London School of Hygiene and Tropical Medicine, London, UK. 4Bristol Medical School: Population Health Sciences, University of Bristol, Bristol,
UK. 5Department of Anthropology, University of Zurich, Zurich, Switzerland. *e-mail: md479@cam.ac.uk
A long-standing hypothesis suggests that the transition
from hunting and gathering to agriculture results in people
working harder, spending more time engaged in subsistence
activities and having less leisure time1,2. However, tests of
this hypothesis are obscured by comparing between popula-
tions that vary in ecology and social organization, as well as
subsistence3–6. Here we test this hypothesis by examining
adult time allocation among the Agta—a population of small-
scale hunter-gatherers from the northern Philippines who are
increasingly engaged in agriculture and other non-foraging
work. We find that individuals in camps engaging more in
non-foraging work spend more time involved in out-of-camp
work and have substantially less leisure time. This difference
is largely driven by changes in the time allocation of women,
who spend substantially more time engaged in out-of-camp
work in more agricultural camps. Our results support the
hypothesis that hunting and gathering allows a significant
amount of leisure time, and that this is lost as communities
adopt small-scale agriculture.
Agriculture emerged independently in multiple locations world-
wide from around 12,500 years , and by circa 5,000 years  had
replaced hunting and gathering as the dominant mode of human
subsistence7,8. The transition from foraging to farming is associated
with population growth, sedentism and the emergence of increas-
ingly hierarchical political structures6,7. For individuals, the adoption
of farming has been associated with an increase in fertility9,10 and
a decline in dietary breadth and overall health11,12. Although the
transition from foraging to farming could be readily explained if
early farming were more productive than foraging, estimates sug-
gest that this may not have been the case2, and alternative hypoth-
eses based on environmental, social and demographic parameters
have been proposed13,14.
It has also been suggested that the transition from foraging to
farming results in people working harder, having less leisure time
and being less productive per hour worked2. On the basis of data
from contemporary hunter-gatherer societies, Sahlins1 argued that
hunter-gatherers represent the ‘original affluent society’ who, despite
a lack of material wealth, have a livelihood that allows them to work
only 2–4 h per day. Although this claim challenged the assumption
that the foraging-to-farming transition represented an escape from
an arduous foraging lifestyle, subsequent studies have found that
there is substantial variation among foraging and farming popula-
tions in how much they work3–6,15, that many hunter-gatherers face
substantial annual fluctuations in food availability6, and that many
foraged foods require a substantial amount of time to process once
brought back to camp16. Given this diversity, comparisons between
populations are limited in their ability to isolate the effect of adopt-
ing agriculture on time allocation.
Here, we examine variation in time budgets within a single popu-
lation—the Agta, a community of small-scale politically egalitarian
hunter-gatherers from the northern Philippines who are increas-
ingly engaged in agriculture and other non-foraging work9,17–19. The
Agta live in small camps of fluid membership, within which indi-
viduals cooperate extensively in foraging and food sharing20, and
where ~50% of adults are distantly related or unrelated by kinship21.
We conducted quantitative ethnographic fieldwork with the Agta in
2013 and 2014, collecting data on the time allocation of 359 people
across 10 camps (including 71 adult men and 71 adult women;
>18 years). Time-allocation data were collected through observa-
tional scans. We conducted four scans each day during daylight
hours, with the first scan between 06:30 and 09:00 in the morning
and three more at three-hour intervals. In each scan, we recorded
the activity of all members of the community, grouping activities
into four main categories: childcare, domestic chores, leisure and
out-of-camp work (Supplementary Table 1 and Supplementary
Figs.1 and 2; see Methods for further details). This resulted in a
total of 10,706 person-observations. Out-of-camp work was divided
into two categories: foraging and non-foraging work. Foraging
work consisted of fishing, gathering, honey collecting and hunting.
Although the majority of out-of-camp, non-foraging work con-
sisted of agricultural labour, this category also included activities
such as the collection of non-food items (such as rattan cane) to
sell (see Supplementary Table1 for activity frequencies by category).
Leisure time included socializing, resting, playing and sleeping. Of
adult leisure time (n = 1,491 observations), 71.9% was spent in close
proximity to at least one other adult. Of this time, adults were in
close proximity to an average of 2.20 other adults (s.d. = 2.23). There
was no sex difference in the mean number of these social interac-
tions (men: n = 546 observations; mean = 2.28; s.d. = 1.92; women:
n = 526 observations; mean = 2.13; s.d. = 1.64; P = 0.11; two-tailed
permutation test), and 49% of interactions between adults were with
individuals unrelated through either genetic or affinal kinship.
By comparing across Agta camps that vary in their relative
engagement in foraging versus non-foraging out-of-camp work, we
are able to explore the association between changing livelihoods and
time allocation. We show that across Agta camps, increased engage-
ment in non-foraging out-of-camp work is associated with increased
total out-of-camp work and reduced leisure time, and that there is a
Engagement in agricultural work is associated
with reduced leisure time among Agta
hunter-gatherers
Mark Dyble 1,2*, Jack Thorley1,2, Abigail E. Page3, Daniel Smith 4 and Andrea Bamberg Migliano5
NATURE HUMAN BEHAVIOUR | VOL 3 | AUGUST 2019 | 792–796 | www.nature.com/nathumbehav
792
Content courtesy of Springer Nature, terms of use apply. Rights reserved
... In addition to the specific variables included in each model to assess the effect of environment, ecological risk, and gendered division of food production labour on children's time allocation, all statistical analyses adjusted for the proportion of non-foraged foods consumed in each society. This is because previous studies have found that reliance on domesticated plants and animals is positively correlated with children's time allocation to economic activities 57,84,85 . In what follows, we only discuss results pertaining to Models 3-5. ...
Socioecology shapes child and adolescent time allocation in twelve hunter-gatherer and mixed-subsistence forager societies
Article
Full-text available
  • May 2022
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. Considering the diversity of environments humans inhabit, children’s activities should also reflect local social and ecological opportunities and constraints. To better understand our species’ developmental plasticity, the present paper compiled a time allocation dataset for children and adolescents from twelve hunter-gatherer and mixed-subsistence forager societies (n = 690; 3–18 years; 52% girls). We investigated how environmental factors, local ecological risk, and men and women’s relative energetic contributions were associated with cross-cultural variation in child and adolescent time allocation to childcare, food production, domestic work, and play. Annual precipitation, annual mean temperature, and net primary productivity were not strongly associated with child and adolescent activity budgets. Increased risk of encounters with dangerous animals and dehydration negatively predicted time allocation to childcare and domestic work, but not food production. Gender differences in child and adolescent activity budgets were stronger in societies where men made greater direct contributions to food production than women. We interpret these findings as suggesting that children and their caregivers adjust their activities to facilitate the early acquisition of knowledge which helps children safely cooperate with adults in a range of social and ecological environments. These findings compel us to consider how childhood may have also evolved to facilitate flexible participation in productive activities in early life.
... Our results further contradict any notion of the "original affluent society," according to which hunter-gatherers work~15 hours/week (93,94): Hadza men and women work~50 and 40 hours/week and other hunter-gatherer men and women work~33 and 28 hours/week on average, respectively, based on our crosscultural sample (table S2). Agriculture compared to hunting and gathering is also not necessarily accompanied by increased working time, as has been hotly debated (95). Although some farming groups do work more hours, on average there is no difference in total work time between modes of subsistence (Fig. 8). ...
What we can learn about emotion by talking with the Hadza
Preprint
  • Feb 2022
Instances of emotion are typically understood as internal mental experiences centering on individuals’ subjective feelings. This conceptualization has been supported by studies of emotion narratives, or the stories people tell about events that they understand as emotions. Yet these studies, and contemporary psychology more generally, often rely on observations of educated Europeans and European-Americans, constraining psychological theory and methods. In this paper, we present observations from an inductive, qualitative analysis of emotion narratives of the Hadza, a community of small-scale hunter-gatherers in Tanzania, and juxtapose them with those drawn from Americans from North Carolina. While North Carolina narratives largely conformed to the assumptions of psychological theory, Hadza narratives foregrounded embodied actions involving social others, focused on the sensory environment and immediate needs, and worked outward from situated events as the motivation for behavior. These observations suggest that subjective feeling and internal mental experience may not be the organizing principle of emotion the world-around. Qualitative analysis of emotion narratives from outside of an American (and western) cultural context has the potential to discover additional diversity in meaning-making, offering a descriptive foundation on which to build a more robust and inclusive science of emotion.
... Our results further contradict any notion of the "original affluent society," according to which hunter-gatherers work~15 hours/week (93,94): Hadza men and women work~50 and 40 hours/week and other hunter-gatherer men and women work~33 and 28 hours/week on average, respectively, based on our crosscultural sample (table S2). Agriculture compared to hunting and gathering is also not necessarily accompanied by increased working time, as has been hotly debated (95). Although some farming groups do work more hours, on average there is no difference in total work time between modes of subsistence (Fig. 8). ...
The energetics of uniquely human subsistence strategies
Article
  • Dec 2021
Efficiency leads to leisure Humans are animals—merely another lineage of great apes. However, we have diverged in significant ways from our ape cousins and we are perennially interested in how this happened. Kraft et al . looked at energy intake and expenditure in modern hunter-gatherer societies and great apes. They found that we do not spend less energy while foraging or farming, but we do acquire more energy and at a faster rate than our ape cousins. This difference may have allowed our ancestors to spend more time in contexts that facilitated social learning and cultural development. —SNV
... Yet, this might be crucial since the daily routine of mobile hunter-gatherers consists of out-ofcamp activities like hunting, foraging, or visiting other camps (Kelly 2013) as well as in-camp activities, such as tool manufacture and rest. Each of these may play an important but different role in socializing (Dyble et al. 2019). Thus, because differences in location (in-camp vs. out-of-camp) are closely linked to different activities and levels of security, the benefits of interacting with others, as well as the identities of preferred or "ideal" social partners, might differ depending on task or location. ...
Social status does not predict in-camp integration among egalitarian hunter-gatherer men
Article
  • Oct 2021
In the last few decades, there has been much research regarding the importance of social prestige in shaping the social structure of small-scale societies. While recent studies show that social prestige may have important health consequences, little is known about the extent to which prestige translates into actual in-person interactions and proximity, even though the level of integration into such real-life social networks has been shown to have important health consequences. Here, we determine the extent to which two different domains of social prestige, popularity (being perceived as a friend by others), and hunting reputation (being perceived as a good hunter), translate into GPS-derived in- and out-of-camp proximity networks in a group of egalitarian hunter-gatherer men, the Hadza. We show that popularity and hunting reputation differ in the extent to which they are translated into time spent physically close to each other. Moreover, our findings suggest that in-camp proximity networks, which are commonly applied in studies of small-scale societies, do not show the full picture of Hadza men’s social preferences. While men are in camp, neither popularity nor hunting reputation is associated with being central in the proximity network; however, when out of camp, Hadza men who are popular are more integrated in the proximity networks while men with better hunting reputations are less integrated. Overall, our findings suggest that, to fully understand social preferences among hunter-gatherers, both in-camp and out-of-camp proximity networks should be considered.
... Camp stability was measured as in Smith et al. (2016) by noting the residents of a camp each time it was visited and calculating the amount of change in camp composition over time, with '1' indicating no change in camp composition and '0' representing complete turnover. Engagement in foraging is measured through the amount of time spent foraging as a proportion of all time spent working out of camp and was assessed using time budget data collected in ten of the study camps according to the methods set out in Dyble et al. (2019). ...
Relatedness within and between Agta residential groups
Article
Full-text available
  • Sep 2021
Theoretical models relating to the evolution of human behaviour usually make assumptions about the kinship structure of social groups. Since humans were hunter-gatherers for most of our evolutionary history, data on the composition of contemporary hunter-gatherer groups has long been used to inform these models. Although several papers have taken a broad view of hunter-gatherer social organisation, it is also useful to explore data from single populations in more depth. Here, we describe patterns of relatedness among the Palanan Agta, hunter-gatherers from the northern Philippines. Across 271 adults, mean relatedness to adults across the population is r = 0.01 and to adult campmates is r = 0.074, estimates that are similar to those seen in other hunter-gatherers. We also report the distribution of kin across camps, relatedness and age differences between spouses, and the degree of shared reproductive interest between camp mates, a measure that incorporates affinal kinship. For both this this measure ( s ) and standard relatedness ( r ), we see no major age or sex differences in the relatedness of adults to their campmates, conditions that may reduce the potential for conflicts of interest within social groups.
... Foraging times reported for dozens of hunter-gatherer groups, averaged between males and females, range between 0.8 and 6.8 h d −1 (refs. 2,18,19 ). We therefore set t f,min = 0.5 and t f,max = 8 h d −1 . ...
Global hunter-gatherer population densities constrained by influence of seasonality on diet composition
Article
Full-text available
The dependence of hunter-gatherers on local net primary production (NPP) to provide food played a major role in shaping long-term human population dynamics. Observations of contemporary hunter-gatherers have shown an overall correlation between population density and annual NPP but with a 1,000-fold variation in population density per unit NPP that remains unexplained. Here, we build a process-based hunter-gatherer population model embedded within a global terrestrial biosphere model, which explicitly addresses the extraction of NPP through dynamically allocated hunting and gathering activities. The emergent results reveal a strong, previously unrecognized effect of seasonality on population density via diet composition, whereby hunter-gatherers consume high fractions of meat in regions where growing seasons are short, leading to greatly reduced population density due to trophic inefficiency. This seasonal carnivory bottleneck largely explains the wide variation in population density per unit NPP and questions the prevailing usage of annual NPP as the proxy of carrying capacity for ancient humans. Our process-based approach has the potential to greatly refine our understanding of dynamical responses of ancient human populations to past environmental changes. The authors construct a process-based hunter-gatherer population model embedded within a global terrestrial biosphere model that reveals a strong effect of growing season length on population density via diet composition.
Cooperation and Partner Choice Among Agta Hunter-Gatherer Children: An Evolutionary Developmental Perspective
Preprint
Full-text available
  • Mar 2022
Examining development is essential for a full understanding of behaviour, including how individuals acquire traits and how adaptive evolutionary forces shape these processes. The present study explores cooperative development among the Agta, a Filipino hunter-gatherer population. A simple resource allocation game assessing both levels of cooperation (how much children shared) and patterns of partner choice (who they shared with) was played with 179 children between the ages of 3 and 18. Children were given five resources (candies) and for each was asked whether to keep it for themselves or share with someone else, and if so, who this was. Between-camp variation in children’s cooperative behaviour was substantial, and the only strong predictor of children’s cooperation was the average level of cooperation among adults in camp; that is, children were more cooperative in camps where adults were more cooperative. Neither age, sex, relatedness or parental levels of cooperation were strongly associated with the amount children shared. Children preferentially shared with close kin (especially siblings), although older children increasingly shared with less-related individuals. Findings are discussed in terms of their implications for understanding cross-cultural patterns of children’s cooperation, and broader links with human cooperative childcare and life history evolution.
“Progress,” Morality, and “Good” and “Evil”
Chapter
  • Jan 2022
Almost any person has made questions about what is moral and what is immoral, and numerous philosophers and literally thousands of publications have focused on this topic. The aim of this chapter is not to provide a comprehensive or extensive review on the history of these questions and on complex issues such as the links between morality, consequentialism, deontology, utilitarianism, the philosophy of happiness, and so on (see for instance Box 8.1). Instead, here I will provide a brief discussion on some of those issues that are directly related within the main topics covered in the present book and the information provided in the previous chapters. In order to do so, I will start with what Vaas stated in his 2009 book chapter, which we partially discussed mentioned in Chap. 2:
Cross-cultural variation in child and adolescent time allocation to work and play in twelve hunter-gatherer and mixed-subsistence societies
Preprint
Full-text available
  • Sep 2021
Understanding how socioecology affects contemporary children’s learning and work opportunities can help researchers better model the selection pressures which have shaped the evolution of human life history and social organization. Here, we compiled a global time allocation dataset for children and adolescents from hunter-gatherer and mixed-subsistence societies. We investigated how society-level variables including adult sexual division of labour, ecological risk, and climate related to variation in childcare, food production, domestic work, and play. We found that adult sexual division of labour predicted increased sex differences in time allocation, especially childcare. Children in safer ecologies allocated more time to childcare and domestic work, but ecological risk did not strongly predict participation in food production. Climate did not predict child and adolescent time allocation. We argue that by coordinating labour across age and sex, children may simultaneously learn to navigate challenges in their environment while safely participating in productive activities.
Sustainability of social–ecological systems: The difference between social rules and management rules
Article
Full-text available
  • Jul 2021
Most conservation and development initiatives assume that rules limiting resource extraction are necessary for ecological sustainability. While this is often true, in some social–ecological systems, unpredictable ecosystem dynamics and limited exploitation technology make it unlikely that people will overstep the ecological threshold, precluding the need for management rules. Here, two kinds of systems can emerge: open access systems in which individuals can meet their needs without cooperating with others, and a cooperative open access system in which social rules are required though management rules are not, because individuals need to cooperate to survive and to prevent erosion of cooperation by free‐riders. We provide three brief case studies illustrating cooperative open access: Pantaneiro fishers, Agta hunter‐gatherers, and Maasai pastoralists. We conclude that understanding these exceptions is pivotal for a better theoretical understanding of social–ecological systems, and can be valuable in building a strategic approach to conservation.
Inclusive fitness for in-laws
Article
Full-text available
  • Oct 2018
Cooperation among kin is common across the natural world and can be explained in terms of inclusive fitness theory, which holds that individuals can derive indirect fitness benefits from aiding genetically related individuals. However, human kinship includes not only genetic kin but also kin by marriage: our affines (in-laws) and spouses. Can cooperation between these genetically unrelated kin be reconciled with inclusive fitness theory? Here, we argue that although affinal kin and spouses do not necessarily share genetic ancestry, they may have shared genetic interests in future reproduction and, as such, can derive indirect fitness benefits though cooperating. We use standard inclusive fitness theory to derive a coefficient of shared reproductive interest (s) that predicts altruistic investment both in genetic kin and in spouses and affines. Specifically, a behaviour that reduces the fitness of the actor by c and increases the fitness of the recipient by b will be favoured by natural selection when sb > c We suggest that the coefficient of shared reproductive interest may provide a valuable tool for understanding not only the evolution of human kinship but also cooperation and conflict across the natural world more generally.
Advanced Bayesian Multilevel Modeling with the R Package brms
Article
Full-text available
  • Jul 2018
The brms package allows R users to easily specify a wide range of Bayesian single-level and multilevel models which are fit with the probabilistic programming language Stan behind the scenes. Several response distributions are supported, of which all parameters (e.g., location, scale, and shape) can be predicted. Non-linear relationships may be specified using non-linear predictor terms or semi-parametric approaches such as splines or Gaussian processes. Multivariate models can be fit as well. To make all of these modeling options possible in a multilevel framework, brms provides an intuitive and powerful formula syntax, which extends the well known formula syntax of lme4. The purpose of the present paper is to introduce this syntax in detail and to demonstrate its usefulness with four examples, each showing relevant aspects of the syntax.
Multinomial analysis of behavior: statistical methods
Article
Full-text available
Behavioral ecologists frequently use observational methods, such as instantaneous scan sampling, to record the behavior of animals at discrete moments in time. We develop and apply multilevel, multinomial logistic regression models for analyzing such data. These statistical methods correspond to the multinomial character of the response variable while also accounting for the repeated observations of individuals that characterize behavioral datasets. Correlated random effects potentially reveal individual-level trade-offs across behaviors, allowing for models that reveal the extent to which individuals who regularly engage in one behavior also exhibit relatively more or less of another behavior. Using an example dataset, we demonstrate the estimation of these models using Hamiltonian Monte Carlo algorithms, as implemented in the RStan package in the R statistical environment. The supplemental files include a coding script and data that demonstrate auxiliary functions to prepare the data, estimate the models, summarize the posterior samples, and generate figures that display model predictions. We discuss possible extensions to our approach, including models with random slopes to allow individual-level behavioral strategies to vary over time and the need for models that account for temporal autocorrelation. These models can potentially be applied to a broad class of statistical analyses by behavioral ecologists, focusing on other polytomous response variables, such as behavior, habitat choice, or emotional states. Electronic supplementary material The online version of this article (doi:10.1007/s00265-017-2363-8) contains supplementary material, which is available to authorized users.
Accurate age estimation in small-scale societies
Article
Full-text available
  • Jul 2017
Precise estimation of age is essential in evolutionary anthropology, especially to infer population age structures and understand the evolution of human life history diversity. However, in small-scale societies, such as hunter-gatherer populations, time is often not referred to in calendar years, and accurate age estimation remains a challenge. We address this issue by proposing a Bayesian approach that accounts for age uncertainty inherent to fieldwork data. We developed a Gibbs sampling Markov chain Monte Carlo algorithm that produces posterior distributions of ages for each individual, based on a ranking order of individuals from youngest to oldest and age ranges for each individual. We first validate our method on 65 Agta foragers from the Philippines with known ages, and show that our method generates age estimations that are superior to previously published regression-based approaches. We then use data on 587 Agta collected during recent fieldwork to demonstrate how multiple partial age ranks coming from multiple camps of hunter-gatherers can be integrated. Finally, we exemplify how the distributions generated by our method can be used to estimate important demographic parameters in small-scale societies: here, age-specific fertility patterns. Our flexible Bayesian approach will be especially useful to improve cross-cultural life history datasets for small-scale societies for which reliable age records are difficult to acquire.
The Agricultural Revolution in Prehistory: Why did Foragers become Farmers?
Chapter
  • Oct 2006
As Chapter 1 described, the origins of agriculture have been debated by archaeologists for most of the discipline’s history. The topic has been a particular focus of archaeological field and laboratory research from the middle of the twentieth century onwards. The number of suggested causes that has been proposed over the years for why prehistoric foragers might have become farmers appears almost endless, with everybody joining the party including the lunatic fringe (Table 10.1)! The main course of scholarly debate, though, has been conditioned partly by changing theoretical currents in archaeological thinking and perceptions of present-day or recent foraging and farming societies (Chapter 2) and partly by the application of improved methodologies (Chapter 3). In the regional studies that form the core of this book, I have concentrated primarily on the archaeological evidence left by prehistoric foragers and farmers, in all its richness, from stones to bones to rock art to starch grains (and more besides), though I have also made reference to the contributions of the several other disciplines that have contributed to the debate, including anthropology, ecology, ethnoarchaeology, genetics, geomorphology, linguistics, and palynology (pollen analysis). The next sections briefly review the principal themes that have emerged from those studies, as the basis for some concluding reflections on whether it is possible or desirable to arrive at an overarching explanation or set of explanations for why foragers became farmers. South-West Asia has probably been the focus of more debate on discussions about the origins of agriculture than anywhere else in the world. On the present evidence what can clearly be recognized as the Eurasian system of mixed farming (the cultivation of wheat and barley and the herding of sheep and goats) seems to have developed in this region very early in the Holocene. It underpinned the dramatic development of PPNB villages in and around the ‘hilly flanks’ of the Fertile Crescent some 1,000 years into the Holocene, c.8500 BC. The parts of South-West Asia where these villages came into being were also places where wild cereals, sheep, and goats were naturally located.
Living in a Lean-To: Philippine Negrito Foragers in Transition
Book
  • Jan 1990
A Friend in need is a friend indeed: Need-based sharing, rather than cooperative assortment, predicts experimental resource transfers among Agta hunter-gatherers
Article
Despite much theorizing, the evolutionary reasons why humans cooperate extensively with unrelated individuals are still largely unknown. While reciprocity explains many instances of non-kin cooperation, much remains to be understood. A recent suite of models based upon ‘cooperative assortativity’ suggest that non-kin cooperation can evolve if individuals preferentially assort with certain cooperative phenotypes, such as helping those who help others. Here, we test these assortative hypotheses among the Agta, a population of Filipino hunter-gatherers, using an experimental resource allocation game in which individuals divide resources between themselves and camp-mates. Individuals preferentially shared with less cooperative individuals, arguing against cooperative assortativity as a mechanism sustaining resource transfers in this population. Rather, sharing was often based on the recipient's level of need, in addition to kin-based transfers and reciprocal sharing. Contrary to several recent theoretical accounts, in this real-world setting we find no evidence for cooperative assortativity influencing patterns of cooperation. These results may reflect the demands of living in a foraging ecology characterized by high resource stochasticity, necessitating need-based sharing as a system of long-term reciprocity to mitigate repeated subsistence shortfalls.
Paleopathology at the Origins of Agriculture.
Article
Hunter-gatherer health and development policy: How the promotion of sedentism worsens the Agta's health outcomes
Article
Many hunter-gatherer groups live on the outskirts of wider society, experiencing poor health outcomes with little access to medical care. From a development perspective, key interventions include the sedentarisation of these mobile peoples into camps nearby larger towns with sanitation infrastructure and medical care, as increased access to services is assumed to improve outcomes. However, recent research in the Agta (Philippine foragers from Northeast Luzon) has demonstrated that individuals residing in more 'developed' communities suffer from increased morbidity and mortality. Here, using quantitative and ethnographic data on health collected between 2002 and 2014, we explore why this trend occurs by examining the relationship between key development initiatives with self-reported illness and the uptake of medical interventions with 415 Agta men, women and children. We demonstrate that health outcomes worsen as sedentarisation progresses, despite some increases in medical access. We argue this is because the development paradigm is not evidence-based, but rather stems from an ideological dislike of mobile hunter-gatherer lifestyles. Compounded by cultural insensitivity and daily discrimination , current interventions are ill-suited to the unique needs of hunter-gatherers, and thus ineffective. Based on our findings we offer future short and long-term policy suggestions which seek to reduce the Agta's vulnerability, rather than increase it.
Networks of Food Sharing Reveal the Functional Significance of Multilevel Sociality in Two Hunter-Gatherer Groups
Article
Like many other mammalian and primate societies [1–4], humans are said to live in multilevel social groups, with individuals situated in a series of hierarchically structured sub-groups [5, 6]. Although this multilevel social organization has been described among contemporary hunter-gatherers [5], questions remain as to the benefits that individuals derive from living in such groups. Here, we show that food sharing among two populations of contemporary hunter-gatherers—the Palanan Agta (Philippines) and Mbendjele BaYaka (Republic of Congo)—reveals similar multilevel social structures, with individuals situated in households, within sharing clusters of 3–4 households, within the wider residential camps, which vary in size. We suggest that these groupings serve to facilitate inter sexual provisioning, kin provisioning, and risk reduction reciprocity, three levels of cooperation argued to be fundamental inhuman societies [7, 8]. Humans have a suite of derived life history characteristics including a long childhood and short inter-birth intervals that make offspring energetically demanding [9] and have moved to a dietary niche that often involves the exploitation of difficult to acquire foods with highly variable return rates [10–12]. This means that human foragers face both day-to-day and more long-term energetic deficits that conspire to make humans energetically interdependent. We suggest that a multilevel social organization allows individuals access to both the food sharing partners required to buffer themselves against energetic shortfalls and the cooperative partners required for skill-based tasks such as cooperative foraging.