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Barry S. Hewlett - One of the best experts on this subject based on the ideXlab platform.
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Patterns of Cannabis Use among Congo Basin Hunter-Gatherers
Journal of Ethnobiology, 2018Co-Authors: Casey J. Roulette, Barry S. HewlettAbstract:Congo Basin Hunter-Gatherers have used cannabis for nearly two centuries, yet ethnographic descriptions of its use are rare or contradictory. We present the results of two projects investigating cannabis use among Congo Basin Hunter-Gatherers. The first study, conducted in the 1970s, was a survey of cannabis use in three populations: Efe archers, Mbuti net-hunters, and Aka net-hunters. The second study, conducted in 2011, was an in-depth biocultural study of cannabis use among one of these groups, the Aka. Methods varied between the studies, but the integration of results from both studies provide insights into: a) common features of Congo Basin Hunter-Gatherer cannabis use across time and space; b) cross-cultural and intracultural diversity in use; and, c) factors influencing changes in use over time. Compared to typical cannabis research populations in Western, developed countries, cannabis use among Congo Basin Hunter-Gatherers involves extensive sharing, such as communal smoking, absence of gender or age proscriptions, perceived performance enhancing effects, and labor-for-cannabis exchanges with neighboring villagers. Cannabis was sometimes the first or the only plant that Congo Hunter-Gatherers domesticated. Consistent with cross-national studies of cannabis use, Congo Basin Hunter-Gatherer cannabis users were typically male, often adolescent or young adult, and (among Aka in 2011) had less material wealth than non-users. Aka cannabis users also had fewer intestinal parasites. Finally, cannabis use varied across time and space both within and between the three groups in ways that reflect differences in the demographic, cultural, and historical features of the populations, especially degree of sedentarization and market integration.
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Teaching in Hunter-Gatherers
Review of Philosophy and Psychology, 2018Co-Authors: Adam H. Boyette, Barry S. HewlettAbstract:Most of what we know about teaching comes from research among people living in large, politically and economically stratified societies with formal education systems and highly specialized roles with a global market economy. In this paper, we review and synthesize research on teaching among contemporary Hunter-Gatherer societies. The Hunter-Gatherer lifeway is the oldest humanity has known and is more representative of the circumstances under which teaching evolved and was utilized most often throughout human history. Research among contemporary Hunter-Gatherers also illustrates a complex pattern of teaching that is both consistent with and distinct from teaching in other small- and large-scale societies with different subsistence practices and cultural forms. In particular, we find that the cultural emphasis on individual autonomy and socio-political egalitarianism among Hunter-Gatherers differently shapes how teaching occurs. For example, teaching clearly exists among Hunter-Gatherers and appears in many forms, including institutionalized instruction in valued cultural and technical skills. However, teaching tends to be less common in Hunter-Gatherer societies because people live in small, intimate egalitarian, groups that support each other’s learning in a variety of ways without teaching. Furthermore, foundational cultural schemas of autonomy and egalitarianism impact the nature of teaching. For example, adults and older children limit their interventions, permitting autonomous learning, and, when they occur, teaching episodes are generally brief, subtle, indirect, and situated in a present activity (i.e. knowledge is not objectified or intended to be generalizable). We discuss the implications of this research in terms of discussions of the evolution of human cognition and the co-evolution of teaching and culture through the process of cultural niche construction.
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A genome scan for genes underlying adult body size differences between Central African Hunter-Gatherers and farmers
Human Genetics, 2018Co-Authors: Trevor J. Pemberton, Alain Froment, Barry S. Hewlett, Paul Verdu, Noémie S. Becker, Cristen J. Willer, Sylvie Le Bomin, Noah A. Rosenberg, Evelyne HeyerAbstract:The evolutionary and biological bases of the Central African “pygmy” phenotype, a characteristic of rainforest Hunter-Gatherers defined by reduced body size compared with neighboring farmers, remain largely unknown. Here, we perform a joint investigation in Central African Hunter-Gatherers and farmers of adult standing height, sitting height, leg length, and body mass index (BMI), considering 358 Hunter-Gatherers and 169 farmers with genotypes for 153,798 SNPs. In addition to reduced standing heights, Hunter-Gatherers have shorter sitting heights and leg lengths and higher sitting/standing height ratios than farmers and lower BMI for males. Standing height, sitting height, and leg length are strongly correlated with inferred levels of farmer genetic ancestry, whereas BMI is only weakly correlated, perhaps reflecting greater contributions of non-genetic factors to body weight than to height. Single- and multi-marker association tests identify one region and eight genes associated with Hunter-Gatherer/farmer status, and 24 genes associated with the height-related traits. Many of these genes have putative functions consistent with roles in determining their associated traits and the pygmy phenotype, and they include three associated with standing height in non-Africans ( PRKG1, DSCAM, MAGI2 ). We find evidence that European height-associated SNPs or variants in linkage disequilibrium with them contribute to standing- and sitting-height determination in Central Africans, but not to the differential status of Hunter-Gatherers and farmers. These findings provide new insights into the biological basis of the pygmy phenotype, and they highlight the potential of cross-population studies for exploring the genetic basis of phenotypes that vary naturally across populations.
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Hunter-Gatherers of the Congo Basin : cultures, histories, and biology of African Pygmies
2017Co-Authors: Barry S. HewlettAbstract:The forest foragers of the Congo Basin, known collectively as "Pygmies," are the largest and most diverse group of active Hunter-Gatherers remaining in the world. At least fifteen different ethno-linguistic groups exist in the Congo Basin with a total population of 250,000 to 350,000 individuals. Extensive knowledge about these groups has accumulated in the last forty years, but readers have been forced to piece together what is known from many sources. French, Japanese, American, and British researchers have conducted the majority of the research; each national research group has its own academic traditions, history, and publications. Here, leading academic authorities from diverse national traditions summarize recent research on forest Hunter-Gatherers. The volume explores the diversity and uniformity of Congo Basin Hunter-Gatherer life by providing detailed but accessible overviews of recent research. It represents the first book in over twenty-five years to provide a comprehensive and holistic overview of African forest Hunter-Gatherers. Chapters discuss the cultural variation in characteristic features of Congo Basin Hunter-Gatherer life, such as their yodeled polyphonic music, pronounced egalitarianism, multiple-child caregiving, and complex relations with neighboring farming groups. Other contributors address theoretical issues, such as why Pygmies are short, how tropical forest Hunter-Gatherers live without the carbohydrates they receive from neighboring farmers, and how Hunter-Gatherer children learn to share so extensively.
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Social Learning and Innovation in Contemporary Hunter-Gatherers - A Cross-Cultural Analysis of Hunter-Gatherer Social Learning
Social Learning and Innovation in Contemporary Hunter-Gatherers, 2016Co-Authors: Zachary H. Garfield, Melissa J. Garfield, Barry S. HewlettAbstract:Social learning among Hunter-Gatherers has been widely discussed in the literature and authors often draw on ethnographic cases to support theoretical models. In this study we report on the cross-cultural occurrence of various modes and processes of social learning in distinct cultural domains from the ethnographic record. To our knowledge this is the first systematic, cross-cultural study of Hunter-Gatherer social learning. We rely on the sample of Hunter-Gatherers in the electronic Human Relations Area Files (eHRAF) to generate our source of ethnographic texts. We have coded and analyzed 982 ethnographic texts from 23 diverse societies. Oblique and vertical transmission appear at similar rates. Various forms of teaching are the most common processes of social learning and account for more than half of all coded texts. Vertical and oblique social learning are predominantly characterized by teaching, whereas horizontal social learning is primarily through collaborative learning. Approximations of age reveal a general developmental pattern in which social learning of miscellaneous skills characterizes infancy, subsistence skills dominate early and middle childhood, and the social learning of religious beliefs are most frequent during adolescence. Across development we identify a reduction in the importance of vertical transmission in favor of oblique transmission, for subsistence skills in particular. These results highlight the importance of teaching in the ethnographic record of Hunter-Gatherer social learning and provide a systematic, cross-cultural, framework for theoretical models to rely on.
Andrea Bamberg Migliano - One of the best experts on this subject based on the ideXlab platform.
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Data from: Polygyny without wealth: popularity in gift games predicts polygyny in BaYaka Pygmies
2018Co-Authors: Nikhil Chaudhary, Gul Deniz Salali, John Thompson, Mark Dyble, Abigail E. Page, Daniel J. Smith, Ruth Mace, Andrea Bamberg MiglianoAbstract:The occurrence of polygynous marriage in hunter–gatherer societies, which do not accumulate wealth, remains largely unexplored since resource availability is dependent on male hunting capacity and limited by the lack of storage. Hunter–gatherer societies offer the greatest insight in to human evolution since they represent the majority of our species' evolutionary history. In order to elucidate the evolution of hunter–gatherer polygyny, we study marriage patterns of BaYaka Pygmies. We investigate (i) rates of polygyny among BaYaka hunter–gatherers; (ii) whether polygyny confers a fitness benefit to BaYaka men; (iii) in the absence of wealth inequalities, what are the alternative explanations for polygyny among the BaYaka. To understand the latter, we explore differences in phenotypic quality (height and strength), and social capital (popularity in gift games). We find polygynous men have increased reproductive fitness; and that social capital and popularity but not phenotypic quality might have been important mechanisms by which some male hunter–gatherers sustained polygynous marriages before the onset of agriculture and wealth accumulation.
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Characterization of Hunter-Gatherer networks and implications for cumulative culture
Nature Human Behaviour, 2017Co-Authors: Andrea Bamberg Migliano, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, James Thompson, Daniel Smith, Jesús Gómez-gardeñes, Sylvain Viguier, Janis StrodsAbstract:Social networks in modern societies are highly structured, usually involving frequent contact with a small number of unrelated ‘friends’1. However, contact network structures in traditional small-scale societies, especially Hunter-Gatherers, are poorly characterized. We developed a portable wireless sensing technology (motes) to study within-camp proximity networks among Agta and BaYaka Hunter-Gatherers in fine detail. We show that Hunter-Gatherer social networks exhibit signs of increased efficiency2 for potential information exchange. Increased network efficiency is achieved through investment in a few strong links among non-kin ‘friends’ connecting unrelated families. We show that interactions with non-kin appear in childhood, creating opportunities for collaboration and cultural exchange beyond family at early ages. We also show that strong friendships are more important than family ties in predicting levels of shared knowledge among individuals. We hypothesize that efficient transmission of cumulative culture3–6 may have shaped human social networks and contributed to our tendency to extend networks beyond kin and form strong non-kin ties. By developing wireless sensors to track social interactions among Hunter-Gatherers in the Republic of the Congo and the Philippines, Migliano et al. find that a few strong friendship ties connecting unrelated families lead to more efficient social networks.
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Camp stability predicts patterns of hunter–gatherer cooperation
Royal Society open science, 2016Co-Authors: Daniel Smith, Andrea Bamberg Migliano, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, James Thompson, Lucio Vinicius, Katie Major, Ruth MaceAbstract:Humans regularly cooperate with non-kin, which has been theorized to require reciprocity between repeatedly interacting and trusting individuals. However, the role of repeated interactions has not previously been demonstrated in explaining real-world patterns of Hunter-Gatherer cooperation. Here we explore cooperation among the Agta, a population of Filipino Hunter-Gatherers, using data from both actual resource transfers and two experimental games across multiple camps. Patterns of cooperation vary greatly between camps and depend on socio-ecological context. Stable camps (with fewer changes in membership over time) were associated with greater reciprocal sharing, indicating that an increased likelihood of future interactions facilitates reciprocity. This is the first study reporting an association between reciprocal cooperation and Hunter-Gatherer band stability. Under conditions of low camp stability individuals still acquire resources from others, but do so via demand sharing (taking from others), rather than based on reciprocal considerations. Hunter-Gatherer cooperation may either be characterized as reciprocity or demand sharing depending on socio-ecological conditions.
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Future Discounting in Congo Basin Hunter-Gatherers Declines with Socio-Economic Transitions.
PLOS ONE, 2015Co-Authors: Gul Deniz Salali, Andrea Bamberg MiglianoAbstract:Humans have a tendency to discount the future; that is we value small, short-term rewards over larger, long-term rewards. The degree of future discounting, however, changes in response to socio-ecological factors. Here, we study Mbendjele BaYaka Hunter-Gatherers of northern Congo and their farmer neighbours to investigate adaptations in inter-temporal preferences in humans. We argue that in immediate-return systems, where food storage is absent and egalitarianism is enforced through levelling mechanisms, future discounting is an adaptive strategy to prevent wealth accumulation and the emergence of hierarchies. This ensures food sharing and allows for survival in unpredictable environments where there is risk of an energy shortfall. On the other hand, when food storage is made possible by the emergence of agriculture or as seen in some delayed-return Hunter-Gatherer populations, wealth accumulation, hierarchies and lower discount rates become the adaptive strategy. Therefore, individuals in immediate-return, egalitarian societies will discount the future more than those in non-egalitarian, delayed-return societies. Consistent with the predictions we found that market integration and socio-economic transitions decrease the future discounting in Mbendjele Hunter-Gatherers. Our measures of socio-economic differences marked this transition in Hunter-Gatherers living in a logging town. The degree of future-discounting was the same between more market-integrated Hunter-Gatherers and their farmer neighbours.
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Polygyny without wealth: popularity in gift games predicts polygyny in BaYaka Pygmies.
Royal Society Open Science, 2015Co-Authors: Nikhil Chaudhary, Gul Deniz Salali, Mark Dyble, Abigail E. Page, Ruth Mace, James Thompson, Daniel Smith, Andrea Bamberg MiglianoAbstract:The occurrence of polygynous marriage in hunter–gatherer societies, which do not accumulate wealth, remains largely unexplored since resource availability is dependent on male hunting capacity and limited by the lack of storage. Hunter–gatherer societies offer the greatest insight in to human evolution since they represent the majority of our species' evolutionary history. In order to elucidate the evolution of hunter–gatherer polygyny, we study marriage patterns of BaYaka Pygmies. We investigate (i) rates of polygyny among BaYaka hunter–gatherers; (ii) whether polygyny confers a fitness benefit to BaYaka men; (iii) in the absence of wealth inequalities, what are the alternative explanations for polygyny among the BaYaka. To understand the latter, we explore differences in phenotypic quality (height and strength), and social capital (popularity in gift games). We find polygynous men have increased reproductive fitness; and that social capital and popularity but not phenotypic quality might have been important mechanisms by which some male hunter–gatherers sustained polygynous marriages before the onset of agriculture and wealth accumulation.
Abigail E. Page - One of the best experts on this subject based on the ideXlab platform.
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Reconstructing prehistoric demography: What role for extant hunter‐gatherers?
Evolutionary anthropology, 2020Co-Authors: Abigail E. Page, Jennifer C FrenchAbstract:Demography is central to biological, behavioral, and cultural evolution. Knowledge of the demography of prehistoric populations of both Homo sapiens and earlier members of the genus Homo is, therefore, key to the study of human evolution. Unfortunately, demographic processes (fertility, mortality, migration) leave little mark on the archeological and paleoanthropological records. One common solution to this issue is the application of demographic data from extant Hunter-Gatherers to prehistory. With the aim of strengthening this line of enquiry, here we outline some pitfalls and their interpretative implications. In doing so, we provide recommendations about the application of Hunter-Gatherer data to the study of demographic trends throughout human evolution. We use published demographic data from extant Hunter-Gatherers to show that it is the diversity seen among extant Hunter-Gatherers-both intra- and inter-population variability-that is most relevant and useful for understanding past Hunter-Gatherer demography.
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Data from: Polygyny without wealth: popularity in gift games predicts polygyny in BaYaka Pygmies
2018Co-Authors: Nikhil Chaudhary, Gul Deniz Salali, John Thompson, Mark Dyble, Abigail E. Page, Daniel J. Smith, Ruth Mace, Andrea Bamberg MiglianoAbstract:The occurrence of polygynous marriage in hunter–gatherer societies, which do not accumulate wealth, remains largely unexplored since resource availability is dependent on male hunting capacity and limited by the lack of storage. Hunter–gatherer societies offer the greatest insight in to human evolution since they represent the majority of our species' evolutionary history. In order to elucidate the evolution of hunter–gatherer polygyny, we study marriage patterns of BaYaka Pygmies. We investigate (i) rates of polygyny among BaYaka hunter–gatherers; (ii) whether polygyny confers a fitness benefit to BaYaka men; (iii) in the absence of wealth inequalities, what are the alternative explanations for polygyny among the BaYaka. To understand the latter, we explore differences in phenotypic quality (height and strength), and social capital (popularity in gift games). We find polygynous men have increased reproductive fitness; and that social capital and popularity but not phenotypic quality might have been important mechanisms by which some male hunter–gatherers sustained polygynous marriages before the onset of agriculture and wealth accumulation.
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Cooperation and the evolution of Hunter-Gatherer storytelling
Nature communications, 2017Co-Authors: Daniel Smith, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, Ruth Mace, James Thompson, Katie Major, Philip Schlaepfer, Leonora AsteteAbstract:Storytelling is a human universal. From gathering around the camp-fire telling tales of ancestors to watching the latest television box-set, humans are inveterate producers and consumers of stories. Despite its ubiquity, little attention has been given to understanding the function and evolution of storytelling. Here we explore the impact of storytelling on Hunter-Gatherer cooperative behaviour and the individual-level fitness benefits to being a skilled storyteller. Stories told by the Agta, a Filipino Hunter-Gatherer population, convey messages relevant to coordinating behaviour in a foraging ecology, such as cooperation, sex equality and egalitarianism. These themes are present in narratives from other foraging societies. We also show that the presence of good storytellers is associated with increased cooperation. In return, skilled storytellers are preferred social partners and have greater reproductive success, providing a pathway by which group-beneficial behaviours, such as storytelling, can evolve via individual-level selection. We conclude that one of the adaptive functions of storytelling among hunter gatherers may be to organise cooperation.
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Characterization of Hunter-Gatherer networks and implications for cumulative culture
Nature Human Behaviour, 2017Co-Authors: Andrea Bamberg Migliano, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, James Thompson, Daniel Smith, Jesús Gómez-gardeñes, Sylvain Viguier, Janis StrodsAbstract:Social networks in modern societies are highly structured, usually involving frequent contact with a small number of unrelated ‘friends’1. However, contact network structures in traditional small-scale societies, especially Hunter-Gatherers, are poorly characterized. We developed a portable wireless sensing technology (motes) to study within-camp proximity networks among Agta and BaYaka Hunter-Gatherers in fine detail. We show that Hunter-Gatherer social networks exhibit signs of increased efficiency2 for potential information exchange. Increased network efficiency is achieved through investment in a few strong links among non-kin ‘friends’ connecting unrelated families. We show that interactions with non-kin appear in childhood, creating opportunities for collaboration and cultural exchange beyond family at early ages. We also show that strong friendships are more important than family ties in predicting levels of shared knowledge among individuals. We hypothesize that efficient transmission of cumulative culture3–6 may have shaped human social networks and contributed to our tendency to extend networks beyond kin and form strong non-kin ties. By developing wireless sensors to track social interactions among Hunter-Gatherers in the Republic of the Congo and the Philippines, Migliano et al. find that a few strong friendship ties connecting unrelated families lead to more efficient social networks.
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Camp stability predicts patterns of hunter–gatherer cooperation
Royal Society open science, 2016Co-Authors: Daniel Smith, Andrea Bamberg Migliano, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, James Thompson, Lucio Vinicius, Katie Major, Ruth MaceAbstract:Humans regularly cooperate with non-kin, which has been theorized to require reciprocity between repeatedly interacting and trusting individuals. However, the role of repeated interactions has not previously been demonstrated in explaining real-world patterns of Hunter-Gatherer cooperation. Here we explore cooperation among the Agta, a population of Filipino Hunter-Gatherers, using data from both actual resource transfers and two experimental games across multiple camps. Patterns of cooperation vary greatly between camps and depend on socio-ecological context. Stable camps (with fewer changes in membership over time) were associated with greater reciprocal sharing, indicating that an increased likelihood of future interactions facilitates reciprocity. This is the first study reporting an association between reciprocal cooperation and Hunter-Gatherer band stability. Under conditions of low camp stability individuals still acquire resources from others, but do so via demand sharing (taking from others), rather than based on reciprocal considerations. Hunter-Gatherer cooperation may either be characterized as reciprocity or demand sharing depending on socio-ecological conditions.
Gul Deniz Salali - One of the best experts on this subject based on the ideXlab platform.
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Data from: Polygyny without wealth: popularity in gift games predicts polygyny in BaYaka Pygmies
2018Co-Authors: Nikhil Chaudhary, Gul Deniz Salali, John Thompson, Mark Dyble, Abigail E. Page, Daniel J. Smith, Ruth Mace, Andrea Bamberg MiglianoAbstract:The occurrence of polygynous marriage in hunter–gatherer societies, which do not accumulate wealth, remains largely unexplored since resource availability is dependent on male hunting capacity and limited by the lack of storage. Hunter–gatherer societies offer the greatest insight in to human evolution since they represent the majority of our species' evolutionary history. In order to elucidate the evolution of hunter–gatherer polygyny, we study marriage patterns of BaYaka Pygmies. We investigate (i) rates of polygyny among BaYaka hunter–gatherers; (ii) whether polygyny confers a fitness benefit to BaYaka men; (iii) in the absence of wealth inequalities, what are the alternative explanations for polygyny among the BaYaka. To understand the latter, we explore differences in phenotypic quality (height and strength), and social capital (popularity in gift games). We find polygynous men have increased reproductive fitness; and that social capital and popularity but not phenotypic quality might have been important mechanisms by which some male hunter–gatherers sustained polygynous marriages before the onset of agriculture and wealth accumulation.
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Cooperation and the evolution of Hunter-Gatherer storytelling
Nature communications, 2017Co-Authors: Daniel Smith, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, Ruth Mace, James Thompson, Katie Major, Philip Schlaepfer, Leonora AsteteAbstract:Storytelling is a human universal. From gathering around the camp-fire telling tales of ancestors to watching the latest television box-set, humans are inveterate producers and consumers of stories. Despite its ubiquity, little attention has been given to understanding the function and evolution of storytelling. Here we explore the impact of storytelling on Hunter-Gatherer cooperative behaviour and the individual-level fitness benefits to being a skilled storyteller. Stories told by the Agta, a Filipino Hunter-Gatherer population, convey messages relevant to coordinating behaviour in a foraging ecology, such as cooperation, sex equality and egalitarianism. These themes are present in narratives from other foraging societies. We also show that the presence of good storytellers is associated with increased cooperation. In return, skilled storytellers are preferred social partners and have greater reproductive success, providing a pathway by which group-beneficial behaviours, such as storytelling, can evolve via individual-level selection. We conclude that one of the adaptive functions of storytelling among hunter gatherers may be to organise cooperation.
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Characterization of Hunter-Gatherer networks and implications for cumulative culture
Nature Human Behaviour, 2017Co-Authors: Andrea Bamberg Migliano, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, James Thompson, Daniel Smith, Jesús Gómez-gardeñes, Sylvain Viguier, Janis StrodsAbstract:Social networks in modern societies are highly structured, usually involving frequent contact with a small number of unrelated ‘friends’1. However, contact network structures in traditional small-scale societies, especially Hunter-Gatherers, are poorly characterized. We developed a portable wireless sensing technology (motes) to study within-camp proximity networks among Agta and BaYaka Hunter-Gatherers in fine detail. We show that Hunter-Gatherer social networks exhibit signs of increased efficiency2 for potential information exchange. Increased network efficiency is achieved through investment in a few strong links among non-kin ‘friends’ connecting unrelated families. We show that interactions with non-kin appear in childhood, creating opportunities for collaboration and cultural exchange beyond family at early ages. We also show that strong friendships are more important than family ties in predicting levels of shared knowledge among individuals. We hypothesize that efficient transmission of cumulative culture3–6 may have shaped human social networks and contributed to our tendency to extend networks beyond kin and form strong non-kin ties. By developing wireless sensors to track social interactions among Hunter-Gatherers in the Republic of the Congo and the Philippines, Migliano et al. find that a few strong friendship ties connecting unrelated families lead to more efficient social networks.
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Camp stability predicts patterns of hunter–gatherer cooperation
Royal Society open science, 2016Co-Authors: Daniel Smith, Andrea Bamberg Migliano, Gul Deniz Salali, Nikhil Chaudhary, Mark Dyble, Abigail E. Page, James Thompson, Lucio Vinicius, Katie Major, Ruth MaceAbstract:Humans regularly cooperate with non-kin, which has been theorized to require reciprocity between repeatedly interacting and trusting individuals. However, the role of repeated interactions has not previously been demonstrated in explaining real-world patterns of Hunter-Gatherer cooperation. Here we explore cooperation among the Agta, a population of Filipino Hunter-Gatherers, using data from both actual resource transfers and two experimental games across multiple camps. Patterns of cooperation vary greatly between camps and depend on socio-ecological context. Stable camps (with fewer changes in membership over time) were associated with greater reciprocal sharing, indicating that an increased likelihood of future interactions facilitates reciprocity. This is the first study reporting an association between reciprocal cooperation and Hunter-Gatherer band stability. Under conditions of low camp stability individuals still acquire resources from others, but do so via demand sharing (taking from others), rather than based on reciprocal considerations. Hunter-Gatherer cooperation may either be characterized as reciprocity or demand sharing depending on socio-ecological conditions.
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Future Discounting in Congo Basin Hunter-Gatherers Declines with Socio-Economic Transitions.
PLOS ONE, 2015Co-Authors: Gul Deniz Salali, Andrea Bamberg MiglianoAbstract:Humans have a tendency to discount the future; that is we value small, short-term rewards over larger, long-term rewards. The degree of future discounting, however, changes in response to socio-ecological factors. Here, we study Mbendjele BaYaka Hunter-Gatherers of northern Congo and their farmer neighbours to investigate adaptations in inter-temporal preferences in humans. We argue that in immediate-return systems, where food storage is absent and egalitarianism is enforced through levelling mechanisms, future discounting is an adaptive strategy to prevent wealth accumulation and the emergence of hierarchies. This ensures food sharing and allows for survival in unpredictable environments where there is risk of an energy shortfall. On the other hand, when food storage is made possible by the emergence of agriculture or as seen in some delayed-return Hunter-Gatherer populations, wealth accumulation, hierarchies and lower discount rates become the adaptive strategy. Therefore, individuals in immediate-return, egalitarian societies will discount the future more than those in non-egalitarian, delayed-return societies. Consistent with the predictions we found that market integration and socio-economic transitions decrease the future discounting in Mbendjele Hunter-Gatherers. Our measures of socio-economic differences marked this transition in Hunter-Gatherers living in a logging town. The degree of future-discounting was the same between more market-integrated Hunter-Gatherers and their farmer neighbours.
Geoffrey B. West - One of the best experts on this subject based on the ideXlab platform.
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the ecological and evolutionary energetics of hunter gatherer residential mobility
Evolutionary Anthropology, 2016Co-Authors: Marcus J Hamilton, Jose Lobo, Eric Rupley, Hyejin Youn, Geoffrey B. WestAbstract:Residential mobility is a key aspect of Hunter-Gatherer foraging economies and therefore is an issue of central importance in Hunter-Gatherer studies.[1-7] Hunter-Gatherers vary widely in annual rates of residential mobility. Understanding the sources of this variation has long been of interest to anthropologists and archeologists. The vast majority of Hunter-Gatherers who are dependent on terrestrial plants and animals move camp multiple times a year because local foraging patches become depleted and food, material, and social resources are heterogeneously distributed through time and space. In some environments, particularly along coasts, where resources are abundant and predictable, Hunter-Gatherers often become effectively sedentary. But even in these special cases, a central question is how these societies have maintained viable foraging economies while reducing residential mobility to near zero.
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the ecological and evolutionary energetics of hunter gatherer residential mobility
arXiv: Physics and Society, 2016Co-Authors: Marcus J Hamilton, Jose Lobo, Eric Rupley, Hyejin Youn, Geoffrey B. WestAbstract:Residential mobility is deeply entangled with all aspects of Hunter-Gatherer life ways, and is therefore an issue of central importance in Hunter-Gatherer studies. Hunter-Gatherers vary widely in annual rates of residential mobility, and understanding the sources of this variation has long been of interest to anthropologists and archaeologists. Since mobility is, to a large extent, driven by the need for a continuous supply of food, a natural framework for addressing this question is provided by the metabolic theory of ecology. This provides a powerful framework for formulating formal testable hypotheses concerning evolutionary and ecological constraints on the scale and variation of Hunter-Gatherer residential mobility. We evaluate these predictions using extant data and show strong support for the hypotheses. We show that the overall scale of Hunter-Gatherer residential mobility is predicted by average human body size, and the limited capacity of mobile Hunter-Gatherers to store energy internally. We then show that the majority of variation in residential mobility observed across cultures is predicted by energy availability in local ecosystems. Our results demonstrate that large-scale evolutionary and ecological processes, common to all plants and animals, constrain Hunter-Gatherers in predictable ways as they move through territories to effectively exploit resources over the course of a year. Moreover, our results extend the scope of the metabolic theory of ecology by showing how it successfully predicts variation in the behavioral ecology of populations within a species.