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Bickel B, Giraud AL, Zuberbühler K, van Schaik CP. Language follows a distinct mode of extra-genomic evolution. Phys Life Rev 2024; 50:211-225. [PMID: 39153248 DOI: 10.1016/j.plrev.2024.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2024] [Accepted: 08/02/2024] [Indexed: 08/19/2024]
Abstract
As one of the most specific, yet most diverse of human behaviors, language is shaped by both genomic and extra-genomic evolution. Sharing methods and models between these modes of evolution has significantly advanced our understanding of language and inspired generalized theories of its evolution. Progress is hampered, however, by the fact that the extra-genomic evolution of languages, i.e. linguistic evolution, maps only partially to other forms of evolution. Contrasting it with the biological evolution of eukaryotes and the cultural evolution of technology as the best understood models, we show that linguistic evolution is special by yielding a stationary dynamic rather than stable solutions, and that this dynamic allows the use of language change for social differentiation while maintaining its global adaptiveness. Linguistic evolution furthermore differs from technological evolution by requiring vertical transmission, allowing the reconstruction of phylogenies; and it differs from eukaryotic biological evolution by foregoing a genotype vs phenotype distinction, allowing deliberate and biased change. Recognising these differences will improve our empirical tools and open new avenues for analyzing how linguistic, cultural, and biological evolution interacted with each other when language emerged in the hominin lineage. Importantly, our framework will help to cope with unprecedented scientific and ethical challenges that presently arise from how rapid cultural evolution impacts language, most urgently from interventional clinical tools for language disorders, potential epigenetic effects of technology on language, artificial intelligence and linguistic communicators, and global losses of linguistic diversity and identity. Beyond language, the distinctions made here allow identifying variation in other forms of biological and cultural evolution, developing new perspectives for empirical research.
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Affiliation(s)
- Balthasar Bickel
- Department of Comparative Language Science, University of Zurich, Switzerland; Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Switzerland.
| | - Anne-Lise Giraud
- Department of Basic Neurosciences, University of Geneva, Switzerland; Institut de l'Audition, Institut Pasteur, INSERM, Université Paris Cité, France
| | - Klaus Zuberbühler
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Switzerland; Institute of Biology, University of Neuchâtel, Switzerland; School of Psychology and Neuroscience, University of St Andrews, United Kingdom
| | - Carel P van Schaik
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Switzerland; Department of Evolutionary Biology and Environmental Science, University of Zurich, Switzerland; Max Planck Institute for Animal Behavior, Konstanz, Germany
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2
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Dyble M. Explaining variation in the kinship composition of mammal groups. Behav Ecol 2024; 35:arae032. [PMID: 38690088 PMCID: PMC11059295 DOI: 10.1093/beheco/arae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 03/12/2024] [Accepted: 04/16/2024] [Indexed: 05/02/2024] Open
Abstract
Variation in cooperative behavior across mammals is strongly related to the kinship composition of groups. Although the factors affecting average genetic relatedness within groups have been studied, the factors that contribute to the production of different categories of kin remain underexplored. Here, I use a mathematical model to explore the factors that determine the proportion of full siblings, maternal half-siblings, paternal half-siblings, and non-siblings within mammal groups. The results suggest that the production of paternal half-siblings is increased by high male reproductive skew and a female-biased sex ratio, the production of maternal half-siblings is increased by high female reproductive skew and male-biased sex ratio, and that there are two routes to the production of full siblings: either high reproductive skew in both sexes (as seen in cooperatively breeding species) or pair-bond stability within groups of low reproductive skew (as seen in humans). These results broadly correspond to observed variation in sibling composition across mammals.
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Affiliation(s)
- Mark Dyble
- Department of Archaeology, University of Cambridge, Downing Street, CB2 3DZ Cambridge, United Kingdom
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3
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Salles T, Joannes-Boyau R, Moffat I, Husson L, Lorcery M. Physiography, foraging mobility, and the first peopling of Sahul. Nat Commun 2024; 15:3430. [PMID: 38653772 DOI: 10.1038/s41467-024-47662-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 04/09/2024] [Indexed: 04/25/2024] Open
Abstract
The route and speed of migration into Sahul by Homo sapiens remain a major research question in archaeology. Here, we introduce an approach which models the impact of the physical environment on human mobility by combining time-evolving landscapes with Lévy walk foraging patterns, this latter accounting for a combination of short-distance steps and occasional longer moves that hunter-gatherers likely utilised for efficient exploration of new environments. Our results suggest a wave of dispersal radiating across Sahul following riverine corridors and coastlines. Estimated migration speeds, based on archaeological sites and predicted travelled distances, fall within previously reported range from Sahul and other regions. From our mechanistic movement simulations, we then analyse the likelihood of archaeological sites and highlight areas in Australia that hold archaeological potential. Our approach complements existing methods and provides interesting perspectives on the Pleistocene archaeology of Sahul that could be applied to other regions around the world.
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Affiliation(s)
- Tristan Salles
- School of Geosciences, The University of Sydney, Sydney, NSW, Australia.
| | - Renaud Joannes-Boyau
- Geoarchaeology and Archaeometry Research Group, Southern Cross University, Lismore, NSW, Australia
| | - Ian Moffat
- Geoarchaeology and Archaeometry Research Group, Southern Cross University, Lismore, NSW, Australia
- Archaeology, College of Humanities, Arts and Social Sciences, Flinders University, Adelaide, SA, Australia
| | - Laurent Husson
- ISTerre, CNRS, Université Grenoble-Alpes, Grenoble, France
| | - Manon Lorcery
- School of Geosciences, The University of Sydney, Sydney, NSW, Australia
- ISTerre, CNRS, Université Grenoble-Alpes, Grenoble, France
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4
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Meijer H. Janus faced: The co-evolution of war and peace in the human species. Evol Anthropol 2024:e22027. [PMID: 38623594 DOI: 10.1002/evan.22027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024]
Abstract
The human species presents a paradox. No other species possesses the propensity to carry out coalitionary lethal attacks on adult conspecifics coupled with the inclination to establish peaceful relations with genetically unrelated groups. What explains this seemingly contradictory feature? Existing perspectives, the "deep roots" and "shallow roots" of war theses, fail to capture the plasticity of human intergroup behaviors, spanning from peaceful cooperation to warfare. By contrast, this article argues that peace and war have both deep roots, and they co-evolved through an incremental process over several million years. On the one hand, humans inherited the propensity for coalitionary lethal violence from their chimpanzee-like ancestor. Specifically, having first inherited the skills to engage in cooperative hunting, they gradually repurposed such capacity to execute coalitionary killings of adult conspecifics and subsequently enhanced it through technological innovations like the use of weapons. On the other hand, they underwent a process of cumulative cultural evolution and, subsequently, of self-domestication which led to heightened cooperative communication and increased prosocial behavior within and between groups. The combination of these two biocultural evolutionary processes-coupled with feedback loop effects between self-domestication and Pleistocene environmental variability-considerably broadened the human intergroup behavioral repertoire, thereby producing the distinctive combination of conflictual and peaceful intergroup relations that characterizes our species. To substantiate this argument, the article synthesizes and integrates the findings from a variety of disciplines, leveraging evidence from evolutionary anthropology, primatology, archeology, paleo-genetics, and paleo-climatology.
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Affiliation(s)
- Hugo Meijer
- Sciences Po, Center for International Studies (CERI), Paris, France
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5
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Overduin-de Vries AM, Vermande MM, Hessen DJ, Sterck EHM. The ability to inhibit impulses is related to social behavior in long-tailed macaques. Am J Primatol 2024; 86:e23587. [PMID: 38145328 DOI: 10.1002/ajp.23587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 11/23/2023] [Accepted: 12/09/2023] [Indexed: 12/26/2023]
Abstract
Performance in cognitive tasks has been linked to differences in species' social organization, yet to understand its function its relationship to within-species variation in behavior should also be explored. One important cognitive capacity, the ability to inhibit impulses, is typically better in egalitarian than despotic primate species and in primate species with strong fission-fusion dynamics. A different line of research indicates that a high ability to inhibit impulses is related to less aggressive behavior and more socio-positive behavior. However, within species the relationship between performance on cognitive inhibition tasks and variation in social behavior remains to be explored. Here we investigate how performance in a typical inhibition task in cognitive research is related to aggressive and socio-positive behavior in despotic long-tailed macaques. Twenty individuals living in two naturalistic mixed-sex groups were tested with the Plexiglass Hole Task. Aggressive behavior and three types of socio-positive behavior (neutral/friendly approaches, socio-positive signaling, and grooming others) among group members were measured. Individuals differed in their ability to inhibit impulses. Individuals that were not good at inhibiting impulses showed higher rates of aggressive behavior, but also more socio-positive signals, whereas inhibition was not related to neutral/friendly approaches and grooming. These results confirm the positive link between impulsiveness and aggression. In addition, the results indicate that some social-positive behavior may be enhanced when inhibition is limited. In this species, benefits potentially derived from aggression and socio-positive signals match a low ability to inhibit impulses, suggesting that a low ability to inhibit impulses may actually be advantageous. To understand differences between species in cognitive skills, understanding the benefits of variation in a cognitive capacity within a species is crucial.
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Affiliation(s)
- Anne M Overduin-de Vries
- Animal Behaviour & Cognition, Utrecht University, Utrecht, The Netherlands
- Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Marjolijn M Vermande
- Department of Child and Adolescent Studies, Utrecht University, Utrecht, The Netherlands
| | - David J Hessen
- Department of Methods and Statistics, Utrecht University, Utrecht, The Netherlands
| | - Elisabeth H M Sterck
- Animal Behaviour & Cognition, Utrecht University, Utrecht, The Netherlands
- Biomedical Primate Research Centre, Rijswijk, The Netherlands
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6
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Gilbert BLP, Kessler SE. Could care giving have altered the evolution of human immune strategies? Evol Med Public Health 2024; 12:33-49. [PMID: 38380131 PMCID: PMC10878251 DOI: 10.1093/emph/eoae004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/12/2024] [Indexed: 02/22/2024] Open
Abstract
Life history theory indicates that individuals/species with a slow pace of life invest more in acquired than innate immunity. Factors that decrease the pace of life and predict greater investment in acquired immunity include increased nutritional resources, increased pathogen exposure and decreased risk of extrinsic mortality. Common care behaviors given to sick individuals produce exactly these effects: provisioning increases nutritional resources; hygiene assistance increases disease exposure of carers; and protection can reduce the risk of extrinsic mortality to sick individuals. This study, therefore, investigated under what conditions care giving behaviors might impact immune strategy and pace of life. The study employed an agent-based model approach that simulated populations with varying levels of care giving, disease mortality, disease transmissibility, and extrinsic mortality, enabling measurements of how the immune strategy and age structure of the populations changed over evolutionary time. We used multiple regressions to examine the effects of these variables on immune strategy and the age structure of the population. The findings supported our predictions that care was selected for an acquired immunity. However, the pace of life did not slow as expected. Instead, the population shifted to a faster, but also more cost-intensive reproductive strategy in which care improved child survival by subsidizing the development of acquired immune responses.
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Affiliation(s)
- Bethany L P Gilbert
- Department of Psychology, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Sharon E Kessler
- Department of Psychology, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK
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7
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Pisor AC, Borgerhoff Mulder M, Smith KM. Long-distance social relationships can both undercut and promote local natural resource management. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220269. [PMID: 37952627 PMCID: PMC10645093 DOI: 10.1098/rstb.2022.0269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/05/2023] [Indexed: 11/14/2023] Open
Abstract
The management of large common-pool resources, like fisheries and forests, is more difficult when more people and more communities can access them-a particular problem given increased population sizes, higher mobility and globalized trade in the Anthropocene. Social relationships spanning communities, such as kin relationships, business or trade relationships and friendships, can make management even more challenging by facilitating and transmitting norms of overharvesting. However, these long-distance relationships can also bolster management by transmitting norms for sustainability, promoting interdependence and laying the groundwork for nested management systems. Here, we review the negative and positive impacts of long-distance relationships on local natural resource management (NRM), providing illustrative examples from our field research on forest and fisheries management in Tanzania. Drawing on the evolutionary literature, the development literature and our field data, we offer suggestions for how development partners can avoid the pitfalls of long-distance relationships and how they can use or even deliberately foster long-distance relationships to promote successful local NRM. This article is part of the theme issue 'Evolution and sustainability: gathering the strands for an Anthropocene synthesis'.
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Affiliation(s)
- Anne C. Pisor
- Department of Anthropology, Washington State University, Pullman, WA, USA
- Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, 04103, Leipzig, Germany
| | - Monique Borgerhoff Mulder
- Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, 04103, Leipzig, Germany
- Santa Fe Institute, New Mexico, 87506, NM, USA
- Department of Anthropology, University of California at Davis, Davis, 95616, CA, USA
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8
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Roscoe P. Social Substitutability and the Emergence of War and Segmental, Multilevel Society. HUMAN NATURE (HAWTHORNE, N.Y.) 2023; 34:621-643. [PMID: 38008887 DOI: 10.1007/s12110-023-09465-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/14/2023] [Indexed: 11/28/2023]
Abstract
Raymond Kelly's widely cited Warless Societies and the Origin of War (University of Michigan Press, 2000) seeks to explain the origins of two central signatures of human society: war and segmented-i.e., multilevel-societies. Both, he argues, arose with the emergence of a social-substitutability principle, a rule that establishes a collective identity among a set of individuals such that any one member becomes equivalent to, and responsible for the actions of, the others. This principle emerged during the Holocene, when population increase gave rise to the first lethal ambushes. By its nature, ambush obscures attackers' identities. Those attempting to retaliate for the ambush were therefore obliged to target members of the ambushers' group indiscriminately-i.e., based on a social-substitutability principle. Kelly's proposals draw welcome attention to a widespread, deeply influential, and unsettling human behavior, the disposition to hold everyone in a group culpable for the actions of a few, a proclivity that all too often results in mass slaughter. His general argument, however, is logically and empirically deficient, and cross-cultural evidence on ambush in contact-era New Guinea undermines his anonymity-of-ambush hypothesis. What then accounts for war and multilevel society? The New Guinea evidence strongly supports a contention that social-substitutability behavior arose not from offensive military action (i.e., ambush) but from the defensive military response to ambush. These findings render the social-substitutability argument's unconventional definition of war superfluous, undermine its chronology for the emergence of war, and underwrite an alternative scenario for the origins of multilevel, segmented society.
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Affiliation(s)
- Paul Roscoe
- Department of Anthropology, University of Maine, Orono, ME, 04469, USA.
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9
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Hayes SC, Hofmann SG. A biphasic relational approach to the evolution of human consciousness: Un enfoque relacional bifásico para la evolución de la conciencia humana. Int J Clin Health Psychol 2023; 23:100380. [PMID: 36937548 PMCID: PMC10017357 DOI: 10.1016/j.ijchp.2023.100380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 02/10/2023] [Indexed: 03/09/2023] Open
Abstract
Background/objective Human consciousness is arguably unique, and its features are hard to explain. Continuous and discrete accounts of consciousness are commonly viewed as incompatible, but both have limitations. Continuous accounts cannot readily account for what appears to be unique about human consciousness; discrete accounts have a hard time explaining how human consciousness could have evolved. The present position paper shows how both continuous and discontinuously elements can be combined. Method A biphasic model is constructed by unifying complex systems theory, the evolution of symbolic reasoning as a relational extension of human cooperation, and evolutionary science. The application of this approach to modern views of consciousness is then explored. Results Our analysis suggests that human consciousness may be viewed as a discontinuous event, that emerged from continuous foundations. This biphasic account contains processes that can be targeted clinically. For example, developmentally delayed children with problems in consciousness may be helped by targeting the processes the present account suggests are important at different levels of complexity. Conclusions This biphasic relational approach fits with the evolutionary record and with data on human cognitive development. It may be useful in guiding clinical intervention.
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10
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Andersson C, Czárán T. The transition from animal to human culture-simulating the social protocell hypothesis. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210416. [PMID: 36688383 PMCID: PMC9869448 DOI: 10.1098/rstb.2021.0416] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The origin of human cumulative culture is commonly envisioned as the appearance (some 2.0-2.5 million years ago) of a capacity to faithfully copy the know-how that underpins socially learned traditions. While certainly plausible, this story faces a steep 'startup problem'. For example, it presumes that ape-like early Homo possessed specialized cognitive capabilities for faithful know-how copying and that early toolmaking actually required such a capacity. The social protocell hypothesis provides a leaner story, where cumulative culture may have originated even earlier-as cumulative systems of non-cumulative traditions ('institutions' and 'cultural lifestyles'), via an emergent group-level channel of cultural inheritance. This channel emerges as a side-effect of a specific but in itself unremarkable suite of social group behaviours. It is independent of faithful know-how copying, and an ancestral version is argued to persist in Pan today. Hominin cultural lifestyles would thereby have gained in complexity and sophistication, eventually becoming independent units of selection (socionts) via a cultural evolutionary transition in individuality, abstractly similar to the origin of early cells. We here explore this hypothesis by simulating its basic premises. The model produces the expected behaviour and reveals several additional and non-trivial phenomena as fodder for future work. This article is part of the theme issue 'Human socio-cultural evolution in light of evolutionary transitions'.
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Affiliation(s)
- Claes Andersson
- Department of Space, Earth and Environment, Division for Physical Resource Theory, Complex System Group, Chalmers University of Technology, 412 96 Gothenburg, Sweden,European Centre for Living Technology, University of Venice Ca’ Foscari, Ca' Bottacin, Dorsoduro 3911, Calle Crosera, 30123 Venice, Italy
| | - Tamás Czárán
- Evolutionary Systems Research Group, ELKH Centre for Ecological Research, Karolina Road 29, H-1113 Budapest, Hungary,Institute of Evolution, ELKH Centre for Ecological Research, Karolina Road 29, H-1113 Budapest, Hungary,ELKH-ELTE Theoretical Biology and Evolutionary Research Group, Eötvös Loránd University, Egyetem tér 1–3, H-1053 Budapest, Hungary
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11
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12
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Lehmann L, Powers ST, van Schaik CP. Four levers of reciprocity across human societies: concepts, analysis and predictions. EVOLUTIONARY HUMAN SCIENCES 2022; 4:e11. [PMID: 37588908 PMCID: PMC10426116 DOI: 10.1017/ehs.2022.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This paper surveys five human societal types - mobile foragers, horticulturalists, pre-state agriculturalists, state-based agriculturalists and liberal democracies - from the perspective of three core social problems faced by interacting individuals: coordination problems, social dilemmas and contest problems. We characterise the occurrence of these problems in the different societal types and enquire into the main force keeping societies together given the prevalence of these. To address this, we consider the social problems in light of the theory of repeated games, and delineate the role of intertemporal incentives in sustaining cooperative behaviour through the reciprocity principle. We analyse the population, economic and political structural features of the five societal types, and show that intertemporal incentives have been adapted to the changes in scope and scale of the core social problems as societies have grown in size. In all societies, reciprocity mechanisms appear to solve the social problems by enabling lifetime direct benefits to individuals for cooperation. Our analysis leads us to predict that as societies increase in complexity, they need more of the following four features to enable the scalability and adaptability of the reciprocity principle: nested grouping, decentralised enforcement and local information, centralised enforcement and coercive power, and formal rules.
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Affiliation(s)
- Laurent Lehmann
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Simon T. Powers
- School of Computing, Edinburgh Napier University, Edinburgh, Scotland, UK
| | - Carel P. van Schaik
- Departments of Anthropology and Evolutionary Biology and Environmental Studies, and Center for the Interdisciplinary Study of Language Evolution, University of Zürich, Zürich, Switzerland
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13
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Pisor AC, Ross CT. Distinguishing Intergroup and Long-Distance Relationships. HUMAN NATURE (HAWTHORNE, N.Y.) 2022; 33:280-303. [PMID: 36181615 PMCID: PMC9741575 DOI: 10.1007/s12110-022-09431-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/07/2022] [Indexed: 11/05/2022]
Abstract
Intergroup and long-distance relationships are both central features of human social life, but because intergroup relationships are emphasized in the literature, long-distance relationships are often overlooked. Here, we make the case that intergroup and long-distance relationships should be studied as distinct, albeit related, features of human sociality. First, we review the functions of both kinds of relationship: while both can be conduits for difficult-to-access resources, intergroup relationships can reduce intergroup conflict whereas long-distance relationships are especially effective at buffering widespread resource shortfalls. Second, to illustrate the importance of distinguishing the two relationship types, we present a case study from rural Bolivia. Combining ethnography and two different experimental techniques, we find that the importance of intergroup relationships-and the salience of group membership itself-varies across populations and across methods. Although ethnography revealed that participants often rely on long-distance relationships for resource access, we were unable to capture participant preferences for these relationships with a forced-choice technique. Taken together, our review and empirical data highlight that (1) intergroup and long-distance relationships can have different functions and can be more or less important in different contexts and (2) validating experimental field data with ethnography is crucial for work on human sociality. We close by outlining future directions for research on long-distance relationships in humans.
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Affiliation(s)
- Anne C. Pisor
- grid.30064.310000 0001 2157 6568Department of Anthropology, Washington State University, Pullman, WA USA ,grid.419518.00000 0001 2159 1813Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Cody T. Ross
- grid.419518.00000 0001 2159 1813Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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14
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Lin KY, Schank JC. Small group size promotes more egalitarian societies as modeled by the hawk-dove game. PLoS One 2022; 17:e0279545. [PMID: 36574418 PMCID: PMC9794044 DOI: 10.1371/journal.pone.0279545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/09/2022] [Indexed: 12/28/2022] Open
Abstract
The social organization of groups varies greatly across primate species, ranging from egalitarian to despotic. Moreover, the typical or average size of groups varies greatly across primate species. Yet we know little about how group size affects social organization across primate species. Here we used the hawk-dove game (HDG) to model the evolution of social organization as a function of maximum group size and used the evolved frequency of hawks as a measure of egalitarian/despotism in societies. That is, the lower the frequency of hawks, the more egalitarian a society is, and the higher the frequency of hawks, the more despotic it is. To do this, we built an agent-based model in which agents live in groups and play the HDG with fellow group members to obtain resources to reproduce offspring. Offspring inherit the strategy of their parent (hawk or dove) with a low mutation rate. When groups reach a specified maximum size, they are randomly divided into two groups. We show that the evolved frequency of hawks is dramatically lower for relatively small maximum group sizes than predicted analytically for the HDG. We discuss the relevance of group size for understanding and modeling primate social systems, including the transition from hunter-gather societies to agricultural societies of the Neolithic era. We conclude that group size should be included in our theoretical understanding of the organization of primate social systems.
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Affiliation(s)
- Kai-Yin Lin
- Department of Psychology, University of California, Davis, Davis, CA, United States of America
| | - Jeffrey C. Schank
- Department of Psychology, University of California, Davis, Davis, CA, United States of America
- * E-mail:
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15
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Brooks J, Yamamoto S. The founder sociality hypothesis. Ecol Evol 2021; 11:14392-14404. [PMID: 34765114 PMCID: PMC8571591 DOI: 10.1002/ece3.8143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/26/2021] [Accepted: 09/01/2021] [Indexed: 11/12/2022] Open
Abstract
In this review, we propose that the social dynamics of founder populations in novel and newly available environments can have critical effects in shaping species' sociality and can produce long-lasting changes in social structure and behavior. For founder populations which expand into an underexploited niche separated from the parent population, the necessity of bond formation with strangers, lack of clear territories, and initial abundance of resources can lead to altered initial social dynamics to which subsequent generations adapt. We call this the founder sociality hypothesis. After specifying the theoretical reasoning and mechanism of effect, we focus on three particular cases where the social dynamics of founder populations may have a central role in explaining their modern behavioral ecology. In particular, we develop and review evidence for three predictions of the founder sociality hypothesis in territorial, mixed-sex group forming species: relatively stronger social bonds in the dispersing sex with relatively weaker bonds in the nondispersing sex, reduced territoriality, and increased social tolerance. We briefly touch on the implications for human evolution given our species' evolutionary history marked by frequent expansion and adaptation to novel environments. We conclude by proposing several experiments and models with testable predictions following from the founder sociality hypothesis.
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Affiliation(s)
- James Brooks
- Wildlife Research CenterKyoto UniversityKyotoJapan
| | - Shinya Yamamoto
- Wildlife Research CenterKyoto UniversityKyotoJapan
- Institute for Advanced StudyKyoto UniversityKyotoJapan
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16
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Grueter CC, Wilson ML. Do we need to reclassify the social systems of gregarious apes? Evol Anthropol 2021; 30:316-326. [PMID: 34343382 DOI: 10.1002/evan.21919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 11/19/2020] [Accepted: 07/01/2021] [Indexed: 11/07/2022]
Abstract
Decades of research have led to a solid understanding of the social systems of gregarious apes: chimpanzees, bonobos, gorillas, and gibbons. As field studies have increasingly collected data from multiple neighboring habituated groups, genetic and social interconnections have been revealed. These findings provide a more nuanced picture of intergroup relations in apes, and have led to claims in the literature that some ape taxa have multilevel societies. A multilevel society is defined as a nested collection of social entities comprising at least two discernible levels of social integration between the individual and the population. We argue that the evidence for multilevel sociality sensu stricto in apes is currently inconclusive and that it is premature to abandon the traditional classification of ape social systems. However, available findings appear to be consistent with the existence of some degree of higher social grouping patterns. We propose the term supra-group organization which may adequately capture ape social systems when viewed from a top-down perspective.
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Affiliation(s)
- Cyril C Grueter
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, The University of Western Australia, Perth, WA, Australia
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
- International Centre of Biodiversity and Primate Conservation, Dali University, Dali, Yunnan, China
| | - Michael L Wilson
- Department of Anthropology, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, Minnesota, USA
- Institute on the Environment, University of Minnesota, St. Paul, Minnesota, USA
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Smith JE, von Rueden CR, van Vugt M, Fichtel C, Kappeler PM. An Evolutionary Explanation for the Female Leadership Paradox. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.676805] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Social influence is distributed unequally between males and females in many mammalian societies. In human societies, gender inequality is particularly evident in access to leadership positions. Understanding why women historically and cross-culturally have tended to be under-represented as leaders within human groups and organizations represents a paradox because we lack evidence that women leaders consistently perform worse than men. We also know that women exercise overt influence in collective group-decisions within small-scale human societies, and that female leadership is pervasive in particular contexts across non-human mammalian societies. Here, we offer a transdisciplinary perspective on this female leadership paradox. Synthesis of social science and biological literatures suggests that females and males, on average, differ in why and how they compete for access to political leadership in mixed-gender groups. These differences are influenced by sexual selection and are moderated by socioecological variation across development and, particularly in human societies, by culturally transmitted norms and institutions. The interplay of these forces contributes to the emergence of female leaders within and across species. Furthermore, females may regularly exercise influence on group decisions in less conspicuous ways and different domains than males, and these underappreciated forms of leadership require more study. We offer a comprehensive framework for studying inequality between females and males in access to leadership positions, and we discuss the implications of this approach for understanding the female leadership paradox and for redressing gender inequality in leadership in humans.
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18
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Sterelny K. Foragers and Their Tools: Risk, Technology and Complexity. Top Cogn Sci 2021; 13:728-749. [PMID: 34291883 DOI: 10.1111/tops.12559] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 06/08/2021] [Accepted: 06/08/2021] [Indexed: 11/29/2022]
Abstract
The subsistence technology of forager communities has varied greatly over space and time. This paper (i) reviews briefly the main causal factors the literature identifies as responsible for this variation; (ii) analyzes in some detail the most prominent idea in the literature on spatial variation:Complex technology is an adaptive response to elevated risks of subsistence failure; (iii) it argues that the alleged empirical support for this hypothesis depends on dubious proxies of risk; (iv) it argues that it fails to explain the subsistence technologies of desert foragers, who generally live with simple technologies in high-risk environments; (v) it offers an alternative analysis, based on the reduced opportunity costs of complex technologies in highly seasonal environments, on the high value of typical forager targets in those environments and their relatively predictable location in space and time; and (v) the paper concludes with a conjecture about the role of environmental variation in toolkit change over deep time.
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Affiliation(s)
- Kim Sterelny
- School of Philosophy, RSSS, Australian National University
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19
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Lindenfors P, Wartel A, Lind J. 'Dunbar's number' deconstructed. Biol Lett 2021; 17:20210158. [PMID: 33947220 PMCID: PMC8103230 DOI: 10.1098/rsbl.2021.0158] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 04/14/2021] [Indexed: 12/14/2022] Open
Abstract
A widespread and popular belief posits that humans possess a cognitive capacity that is limited to keeping track of and maintaining stable relationships with approximately 150 people. This influential number, 'Dunbar's number', originates from an extrapolation of a regression line describing the relationship between relative neocortex size and group size in primates. Here, we test if there is statistical support for this idea. Our analyses on complementary datasets using different methods yield wildly different numbers. Bayesian and generalized least-squares phylogenetic methods generate approximations of average group sizes between 69-109 and 16-42, respectively. However, enormous 95% confidence intervals (4-520 and 2-336, respectively) imply that specifying any one number is futile. A cognitive limit on human group size cannot be derived in this manner.
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Affiliation(s)
- Patrik Lindenfors
- Institute for Futures Studies, Box 591, 101 31 Stockholm, Sweden
- Centre for Cultural Evolution, Stockholm University, Sweden
| | - Andreas Wartel
- Centre for Cultural Evolution, Stockholm University, Sweden
| | - Johan Lind
- Centre for Cultural Evolution, Stockholm University, Sweden
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20
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Anthropological Prosociality via Sub-Group Level Selection. Integr Psychol Behav Sci 2021; 56:180-205. [PMID: 33893612 DOI: 10.1007/s12124-021-09606-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2021] [Indexed: 10/21/2022]
Abstract
A perennial challenge of evolutionary psychology is explaining prosocial traits such as a preference for fairness rather than inequality, compassion towards suffering, and an instinctive ability to coordinate within small teams. Considering recent fossil evidence and a novel logical test, we deem present explanations insufficiently explanatory of the divergence of hominins. In answering this question, we focus on the divergence of hominins from the last common ancestor (LCA) shared with Pan. We consider recent fossil discoveries that indicate the LCA was bipedal, which reduces the cogency of this explanation for hominin development. We also review evolutionary theory that claims to explain how hominins developed into modern humans, however it is found that no mechanism differentiates hominins from other primates. Either the mechanism was available to the last common ancestor (LCA) (with P. troglodytes as its proxy), or because early hominins had insufficient cognition to utilise the mechanism. A novel mechanism, sub-group level selection (sGLS) is hypothesised by triangulating two pieces of data rarely considered by evolutionary biologists. These are behavioural dimorphism of Pan (chimpanzees and bonobos) that remain identifiable in modern humans, and the social behaviour of primate troops in a savannah ecology. We then contend that sGLS supplied an exponential effect which was available to LCA who left the forest, but was not sufficiently available to any other primates. In conclusion, while only indirectly supported by various evidence, sGLS is found to be singularly and persuasively explanatory of human's unique evolutionary story.
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21
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Dyble M. The evolution of altruism through war is highly sensitive to population structure and to civilian and fighter mortality. Proc Natl Acad Sci U S A 2021; 118:e2011142118. [PMID: 33836563 PMCID: PMC7980410 DOI: 10.1073/pnas.2011142118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The importance of warfare in the evolution of human social behavior remains highly debated. One hypothesis is that intense warfare between groups favored altruism within groups, a hypothesis given some support by computational modeling and, in particular, the work of Choi and Bowles [J.-K. Choi, S. Bowles, Science 318, 636-640 (2007)]. The results of computational models are, however, sensitive to chosen parameter values and a deeper assessment of the plausibility of the parochial altruism hypothesis requires exploring this model in more detail. Here, I use a recently developed method to reexamine Choi and Bowles' model under a much broader range of conditions to those used in the original paper. Although the evolution of altruism is robust to perturbations in most of the default parameters, it is highly sensitive to group size and migration and to the lethality of war. The results show that the degree of genetic differentiation between groups (FST ) produced by Choi and Bowles' original model is much greater than empirical estimates of FST between hunter-gatherer groups. When FST in the model is close to empirically observed values, altruism does not evolve. These results cast doubt on the importance of war in the evolution of human sociality.
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Affiliation(s)
- Mark Dyble
- Department of Anthropology, University College London, WC1H 0BW London, United Kingdom
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Spikins P, French JC, John-Wood S, Dytham C. Theoretical and Methodological Approaches to Ecological Changes, Social Behaviour and Human Intergroup Tolerance 300,000 to 30,000 BP. JOURNAL OF ARCHAEOLOGICAL METHOD AND THEORY 2021; 28:53-75. [PMID: 33679119 PMCID: PMC7891228 DOI: 10.1007/s10816-020-09503-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/15/2020] [Indexed: 05/13/2023]
Abstract
UNLABELLED Archaeological evidence suggests that important shifts were taking place in the character of human social behaviours 300,000 to 30,000 years ago. New artefact types appear and are disseminated with greater frequency. Transfers of both raw materials and finished artefacts take place over increasing distances, implying larger scales of regional mobility and more frequent and friendlier interactions between different communities. Whilst these changes occur during a period of increasing environmental variability, the relationship between ecological changes and transformations in social behaviours is elusive. Here, we explore a possible theoretical approach and methodology for understanding how ecological contexts can influence selection pressures acting on intergroup social behaviours. We focus on the relative advantages and disadvantages of intergroup tolerance in different ecological contexts using agent-based modelling (ABM). We assess the relative costs and benefits of different 'tolerance' levels in between-group interactions on survival and resource exploitation in different environments. The results enable us to infer a potential relationship between ecological changes and proposed changes in between-group behavioural dynamics. We conclude that increasingly harsh environments may have driven changes in hormonal and emotional responses in humans leading to increasing intergroup tolerance, i.e. transformations in social behaviour associated with 'self-domestication'. We argue that changes in intergroup tolerance is a more parsimonious explanation for the emergence of what has been seen as 'modern human behaviour' than changes in hard aspects of cognition or other factors such as cognitive adaptability or population size. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10816-020-09503-5.
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Affiliation(s)
- Penny Spikins
- Department of Archaeology, Archaeology PalaeoHub, University of York, York, YO10 5DD UK
| | - Jennifer C. French
- Department of Archaeology, Classics, and Egyptology, University of Liverpool, Liverpool, L69 7WZ UK
| | - Seren John-Wood
- York Cross-disciplinary Centre for Systems Analysis (YCCSA) Internship Programme, University of York, York, UK
- University College London, London, UK
| | - Calvin Dytham
- Department of Biology, University of York, York, YO10 5DD UK
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23
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Nelson RG. Beyond the Household: Caribbean Families and Biocultural Models of Alloparenting. ANNUAL REVIEW OF ANTHROPOLOGY 2020. [DOI: 10.1146/annurev-anthro-102218-011140] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alloparental or extramaternal care is an integral aspect of human childrearing. This behavior has been explored both as an extension of the primary mother–infant dyad that evolved to meet the demands of altricial offspring and as an economic exchange of energy and resources. Much of this research centers on foraging or small-scale communities and positions the household as the central unit through which to explore negotiations of care. In this review, I use evidence from Black Caribbean communities living in industrialized countries to challenge the broad applicability of the analytical model of the bounded household and to question whether our current articulations of theory and empirical assessments of extramaternal care are well suited to investigations of these behaviors in the vast majority of contemporary human populations. Alloparental practices in the Caribbean reflect dynamic responses to maternal migration and the local influence of global labor markets. The children who remain at home experience variability in the care received from their surrogate parents. The dynamic aspect of the care practices enacted by these transnational families reveals the behavioral flexibility that has been integral to human survival.
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Affiliation(s)
- Robin G. Nelson
- Department of Anthropology, Santa Clara University, Santa Clara, California 95053, USA
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24
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Sterelny K. Innovation, life history and social networks in human evolution. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190497. [PMID: 32475328 DOI: 10.1098/rstb.2019.0497] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
There is a famous puzzle about the first 3 million years of archaeologically visible human technological history. The pace of change, of innovation and its uptake, is extraordinarily slow. In particular, the famous handaxes of the Acheulian technological tradition first appeared about 1.7 Ma, and persisted with little change until about 800 ka, perhaps even longer. In this paper, I will offer an explanation of that stasis based in the life history and network characteristics that we infer (on phylogenetic grounds) to have characterized earlier human species. The core ideas are that (i) especially in earlier periods of hominin evolution, we are likely to find archaeological traces only of widespread and persisting technologies and practices; (ii) the record is not a record of the rate of innovation, but the rate of innovations establishing in a landscape; (iii) innovations are extremely vulnerable to stochastic loss while confined to the communities in which they are made and established; (iv) the export of innovation from the local group is sharply constrained if there is a general pattern of hostility and suspicion between groups, or even if there is just little contact between adults of adjoining groups. That pattern is typical of great apes and likely, therefore, to have characterized at least early hominin social lives. Innovations are unlikely to spread by adult-to-adult interactions across community boundaries. (v) Chimpanzees and bonobos are characterized by male philopatry and subadult female dispersal; that is, therefore, the most likely early hominin pattern. If so, the only innovations at all likely to expand beyond the point of origin are those acquired by subadult females, and ones that can be expressed by those females, at high enough frequency and salience for them to spread, in the bands that the females join. These are very serious filters on the spread of innovation. This article is part of the theme issue 'Life history and learning: how childhood, caregiving and old age shape cognition and culture in humans and other animals'.
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Affiliation(s)
- Kim Sterelny
- Department of Philosophy, Australian National University, Coombs Building, Fellows Road, Acton, Canberra, Australian Capital Territory, Australia
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25
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Goren-Inbar N, Belfer-Cohen A. Reappraisal of hominin group size in the Lower Paleolithic: An introduction to the special issue. J Hum Evol 2020; 144:102821. [PMID: 32497921 DOI: 10.1016/j.jhevol.2020.102821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Naama Goren-Inbar
- Institute of Archaeology, The Hebrew University of Jerusalem, Mt. Scopus, 919051, Jerusalem Israel.
| | - Anna Belfer-Cohen
- Institute of Archaeology, The Hebrew University of Jerusalem, Mt. Scopus, 919051, Jerusalem Israel
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26
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Young AW, Frühholz S, Schweinberger SR. Face and Voice Perception: Understanding Commonalities and Differences. Trends Cogn Sci 2020; 24:398-410. [DOI: 10.1016/j.tics.2020.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/16/2020] [Accepted: 02/03/2020] [Indexed: 01/01/2023]
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27
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Furuichi T. Variation in Intergroup Relationships Among Species and Among and Within Local Populations of African Apes. INT J PRIMATOL 2020. [DOI: 10.1007/s10764-020-00134-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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28
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Lucchesi S, Cheng L, Janmaat K, Mundry R, Pisor A, Surbeck M. Beyond the group: how food, mates, and group size influence intergroup encounters in wild bonobos. Behav Ecol 2020. [DOI: 10.1093/beheco/arz214] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abstract
In social-living animals, interactions between groups are frequently agonistic, but they can also be tolerant and even cooperative. Intergroup tolerance and cooperation are regarded as a crucial step in the formation of highly structured multilevel societies. Behavioral ecological theory suggests that intergroup tolerance and cooperation can emerge either when the costs of hostility outweigh the benefits of exclusive resource access or when both groups gain fitness benefits through their interactions. However, the factors promoting intergroup tolerance are still unclear due to the paucity of data on intergroup interactions in tolerant species. Here, we examine how social and ecological factors affect the onset and termination of intercommunity encounters in two neighboring communities of wild bonobos, a species exhibiting flexible patterns of intergroup interactions, at Kokolopori Bonobo Reserve, Democratic Republic of the Congo. We recorded the timing and location of intercommunity encounters and measured fruit abundance and distribution, groups’ social characteristics, and space-use dynamics over a 19-month period. We found that intercommunity tolerance was facilitated by a decrease in feeding competition, with high fruit abundance increasing the likelihood of communities to encounter, and high clumpiness of fruit patches increasing the probability to terminate encounters likely due to increased contest. In addition, the possibility for extra-community mating, as well as the potential benefits of more efficient foraging in less familiar areas, reduced the probability that the communities terminated encounters. By investigating the factors involved in shaping relationships across groups, this study contributes to our understanding of how animal sociality can extend beyond the group level.
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Affiliation(s)
- Stefano Lucchesi
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Leveda Cheng
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Karline Janmaat
- Institute for Biodiversity and Ecosystem Dynamics, Faculty of Science, University of Amsterdam, Amsterdam, The Netherlands
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Universitätsstrasse 10, Konstanz, Germany
| | - Roger Mundry
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Anne Pisor
- Department of Anthropology, Washington State University, Pullman, WA, USA
| | - Martin Surbeck
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
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29
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Swedell L, Plummer T. Social evolution in Plio-Pleistocene hominins: Insights from hamadryas baboons and paleoecology. J Hum Evol 2019; 137:102667. [PMID: 31629289 DOI: 10.1016/j.jhevol.2019.102667] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 08/21/2019] [Accepted: 08/23/2019] [Indexed: 11/16/2022]
Abstract
Reconstructions of hominin evolution have long benefited from comparisons with nonhuman primates, especially baboons and chimpanzees. The hamadryas baboon (Papio hamadryas) is arguably one of the best such models, as it exhibits both the male kin bonding and the cross-sex pair bonding thought to have been important in hominin evolution. Here we link processes of behavioral evolution in hamadryas baboons with those in a Plio-Pleistocene hominin, provisionally identified as Homo erectus (sensu lato) - a pivotal species in that its larger body and brain size and wider ranging patterns increased female costs of reproduction, increasing the importance of sociality. The combination of these higher costs of reproduction and shifts in diet and food acquisition have previously been argued to have been alleviated either via strengthening of male-female bonds (involving male provisioning and the evolution of monogamy) or via the assistance of older, post-reproductive females (leading to post-reproductive longevity in females, i.e., the grandmother hypothesis). We suggest that both arrangements could have been present in Plio-Pleistocene hominins if they lived in multilevel societies. Here we expand on our earlier scenario with two sets of recent data in support of it, (1) archaeological data from the 2 million year old Oldowan site of Kanjera South, Kenya and other sites that are suggestive of tool dependent foraging on nutrient dense resources (animal carcasses and plant underground storage organs), cooperation, and food sharing; and (2) a pattern of genetic variation in hamadryas baboons that suggests the operation of kin selection among both males and females at multiple levels of society. Taken together, these two sets of data strengthen our model and support the idea of a complex society linked by male-male, male-female, and female-female bonds at multiple levels of social organization in Plio-Pleistocene hominins.
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Affiliation(s)
- Larissa Swedell
- Dept of Anthropology, Queens College, City University of New York, Flushing, NY 11367-1597, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA; Anthropology Program, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA; Biology and Psychology Programs, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA; Dept of Archaeology, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
| | - Thomas Plummer
- Dept of Anthropology, Queens College, City University of New York, Flushing, NY 11367-1597, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA; Anthropology Program, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA.
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30
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Pacifying Hunter-Gatherers. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2019; 30:155-175. [DOI: 10.1007/s12110-019-09340-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Malinsky-Buller A, Hovers E. One size does not fit all: Group size and the late middle Pleistocene prehistoric archive. J Hum Evol 2019; 127:118-132. [PMID: 30777353 DOI: 10.1016/j.jhevol.2018.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 11/02/2018] [Accepted: 11/06/2018] [Indexed: 02/03/2023]
Abstract
The role of demography is often suggested to be a key factor in both biological and cultural evolution. Recent research has shown that the linkage between population size and cultural evolution is not straightforward and emerges from the interplay of many demographic, economic, social and ecological variables. Formal modelling has yielded interesting insights into the complex relationship between population structure, intergroup connectedness, and magnitude and extent of population extinctions. Such studies have highlighted the importance of effective (as opposed to census) population size in transmission processes. At the same time, it remained unclear how such insights can be applied to material culture phenomena in the prehistoric record, especially for deeper prehistory. In this paper we approach the issue of population sizes during the time of the Lower to Middle Paleolithic transition through the proxy of regional trajectories of lithic technological change, identified in the archaeological records from Africa, the Levant, Southwestern and Northwestern Europe. Our discussion of the results takes into consideration the constraints inherent to the archaeological record of deep time - e.g., preservation bias, time-averaging and the incomplete nature of the archaeological record - and of extrapolation from discrete archaeological case studies to an evolutionary time scale. We suggest that technological trajectories of change over this transitional period reflect the robustness of transmission networks. Our results show differences in the pattern and rate of cultural transmission in these regions, from which we infer that information networks, and their underlying effective population sizes, also differed.
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Affiliation(s)
- Ariel Malinsky-Buller
- MONREPOS, Archaeological Research Centre and Museum for Human Behavioural Evolution, Schloss Monrepos, 56567, Neuwied, Germany.
| | - Erella Hovers
- The Institute of Archaeology, The Hebrew University of Jerusalem, Mt. Scopus, 91905, Jerusalem, Israel; International Affiliate, Institute of Human Origins, Arizona State University, Tempe, AZ, USA
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33
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Social Structure Facilitated the Evolution of Care-giving as a Strategy for Disease Control in the Human Lineage. Sci Rep 2018; 8:13997. [PMID: 30262928 PMCID: PMC6160448 DOI: 10.1038/s41598-018-31568-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 08/21/2018] [Indexed: 01/18/2023] Open
Abstract
Humans are the only species to have evolved cooperative care-giving as a strategy for disease control. A synthesis of evidence from the fossil record, paleogenomics, human ecology, and disease transmission models, suggests that care-giving for the diseased evolved as part of the unique suite of cognitive and socio-cultural specializations that are attributed to the genus Homo. Here we demonstrate that the evolution of hominin social structure enabled the evolution of care-giving for the diseased. Using agent-based modeling, we simulate the evolution of care-giving in hominin networks derived from a basal primate social system and the three leading hypotheses of ancestral human social organization, each of which would have had to deal with the elevated disease spread associated with care-giving. We show that (1) care-giving is an evolutionarily stable strategy in kin-based cooperatively breeding groups, (2) care-giving can become established in small, low density groups, similar to communities that existed before the increases in community size and density that are associated with the advent of agriculture in the Neolithic, and (3) once established, care-giving became a successful method of disease control across social systems, even as community sizes and densities increased. We conclude that care-giving enabled hominins to suppress disease spread as social complexity, and thus socially-transmitted disease risk, increased.
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Burkart JM, van Schaik C, Griesser M. Looking for unity in diversity: human cooperative childcare in comparative perspective. Proc Biol Sci 2018; 284:rspb.2017.1184. [PMID: 29237848 DOI: 10.1098/rspb.2017.1184] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/13/2017] [Indexed: 01/31/2023] Open
Abstract
Humans engage in cooperative childcare, which includes some elements not found in other animals, such as the presence of post-reproductive helpers, extensive food sharing among adults and a pervasive sexual division of labour. In animals, cooperative offspring care has typically been studied in two different contexts. The first mainly involves helpers contributing care in cooperatively breeding family groups; the second context is allomaternal care in species usually not categorized as cooperative breeders (e.g. plural and communal breeders, often without male care). Comparative analyses suggest that cooperative breeding and allomaternal care in plural and communal breeders have distinct evolutionary origins, with humans fitting neither pathway entirely. Nevertheless, some critical proximate mechanisms of helping, including hormonal regulators, are likely to be shared across species. Other mechanisms may vary among species, such as social tolerance, proactive prosociality or conditional mother-infant bonding. These are presumably associated with specific details of the care system, such as whether all group members contribute, or whether mothers can potentially raise offspring alone. Thus, cooperative offspring care is seen in different contexts across animal lineages, but may nonetheless share several important psychological characteristics. We end by discussing how work on humans may play a unifying role in studying cooperative offspring care.
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Affiliation(s)
- Judith M Burkart
- Department of Anthropology, University of Zurich, Zurich, Switzerland
| | - Carel van Schaik
- Department of Anthropology, University of Zurich, Zurich, Switzerland
| | - Michael Griesser
- Department of Anthropology, University of Zurich, Zurich, Switzerland.,Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland
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Are We Face Experts? Trends Cogn Sci 2018; 22:100-110. [DOI: 10.1016/j.tics.2017.11.007] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/20/2017] [Accepted: 11/28/2017] [Indexed: 11/21/2022]
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The social organization of Homo ergaster: Inferences from anti-predator responses in extant primates. J Hum Evol 2017; 109:11-21. [PMID: 28688456 DOI: 10.1016/j.jhevol.2017.05.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 04/27/2017] [Accepted: 05/04/2017] [Indexed: 02/02/2023]
Abstract
Patterns of primate socioecology have been used to suggest that the first truly savanna-dwelling hominin, Homo ergaster, lived in sizeable groups. Here, we revisit these estimates and infer additional features of the social organization of these early hominins based on anti-predator responses observed across the primate taxon. We first show that the effect of habitat on primate group size, composition, and sexual dimorphism is negligible after controlling for substrate use and phylogeny: terrestrial species live in larger groups with more and bigger males than arboreal taxa. We next hypothesize that groups can only survive in open habitats if males are able to engage in joint counter-attacks against the large carnivorans typical of such environments. To test this, we analyze reports on primate counter-attacks against known predators and find these are indeed disproportionately frequent in terrestrial taxa living in open habitats, sometimes even involving the use of tentative weapons. If we subsequently only examine the taxa that are particularly adept at this (chimpanzees and baboons), we find an effect of habitat type on group size: groups on the savanna are larger than those in the forest. We thus infer that H. ergaster lived in very large groups with many males that jointly defended the group against carnivorans, and argue that these counter-attacks will readily have turned into confrontational scavenging and cooperative hunting, allowing Homo to move into the niche of social carnivore. These two features (life in very large multi-male groups and a switch to persistent carnivory) shaped the evolution of our lineage to such an extent that the social organization of H. ergaster may already have contained many key elements characterizing modern day foragers: male bonding, incipient male-female friendships with food sharing, a tendency toward endogamy, and the presence of large communities that eventually turned into the ethno-linguistic units we can still recognize today.
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Kessler SE, Bonnell TR, Byrne RW, Chapman CA. Selection to outsmart the germs: The evolution of disease recognition and social cognition. J Hum Evol 2017. [PMID: 28622934 DOI: 10.1016/j.jhevol.2017.02.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The emergence of providing care to diseased conspecifics must have been a turning point during the evolution of hominin sociality. On a population level, care may have minimized the costs of socially transmitted diseases at a time of increasing social complexity, although individual care-givers probably incurred increased transmission risks. We propose that care-giving likely originated within kin networks, where the costs may have been balanced by fitness increases obtained through caring for ill kin. We test a novel hypothesis of hominin cognitive evolution in which disease may have selected for the cognitive ability to recognize when a conspecific is infected. Because diseases may produce symptoms that are likely detectable via the perceptual-cognitive pathways integral to social cognition, we suggest that disease recognition and social cognition may have evolved together. Using agent-based modeling, we test 1) under what conditions disease can select for increasing disease recognition and care-giving among kin, 2) whether providing care produces greater selection for cognition than an avoidance strategy, and 3) whether care-giving alters the progression of the disease through the population. The greatest selection was produced by diseases with lower risks to the care-giver and prevalences low enough not to disrupt the kin networks. When care-giving and avoidance strategies were compared, only care-giving reduced the severity of the disease outbreaks and subsequent population crashes. The greatest selection for increased cognitive abilities occurred early in the model runs when the outbreaks and population crashes were most severe. Therefore, over the course of human evolution, repeated introductions of novel diseases into naïve populations could have produced sustained selection for increased disease recognition and care-giving behavior, leading to the evolution of increased cognition, social complexity, and, eventually, medical care in humans. Finally, we lay out predictions derived from our disease recognition hypothesis that we encourage paleoanthropologists, bioarchaeologists, primatologists, and paleogeneticists to test.
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Affiliation(s)
- Sharon E Kessler
- Department of Anthropology, McGill University, Canada; Durham University, Department of Anthropology, UK.
| | | | - Richard W Byrne
- School of Psychology and Neuroscience, University of St. Andrews, UK
| | - Colin A Chapman
- Department of Anthropology, McGill University, Canada; Wildlife Conservation Society, New York, USA
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Frahm E, Feinberg JM, Schmidt-Magee BA, Wilkinson KN, Gasparyan B, Yeritsyan B, Adler DS. Middle Palaeolithic toolstone procurement behaviors at Lusakert Cave 1, Hrazdan valley, Armenia. J Hum Evol 2016; 91:73-92. [DOI: 10.1016/j.jhevol.2015.10.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 11/27/2022]
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Pandit SA, Pradhan GR, Balashov H, Van Schaik CP. The Conditions Favoring Between-Community Raiding in Chimpanzees, Bonobos, and Human Foragers. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2015; 27:141-59. [DOI: 10.1007/s12110-015-9252-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Guo S, Huang K, Ji W, Garber PA, Li B. The role of kinship in the formation of a primate multilevel society. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2014; 156:606-13. [DOI: 10.1002/ajpa.22677] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 11/18/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Songtao Guo
- Key Laboratory of Resource Biology and Biotechnology in Western China of Ministry of Education and College of Life Sciences; Northwest University; Xi'an 710069 China
| | - Kang Huang
- Key Laboratory of Resource Biology and Biotechnology in Western China of Ministry of Education and College of Life Sciences; Northwest University; Xi'an 710069 China
| | - Weihong Ji
- Human and Wildlife Interactions Research Group Institute of Natural Mathematical Sciences; Massey University; Albany Auckland New Zealand 1311
| | - Paul A. Garber
- Anthropology Department; University Illinois at Urbana-Champaign; Urbana IL 61801
| | - Baoguo Li
- Key Laboratory of Resource Biology and Biotechnology in Western China of Ministry of Education and College of Life Sciences; Northwest University; Xi'an 710069 China
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Pearce E, Moutsiou T. Using obsidian transfer distances to explore social network maintenance in late Pleistocene hunter-gatherers. JOURNAL OF ANTHROPOLOGICAL ARCHAEOLOGY 2014; 36:12-20. [PMID: 25214705 PMCID: PMC4157217 DOI: 10.1016/j.jaa.2014.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Social behaviour is notoriously difficult to study archaeologically and it is unclear how large the networks of prehistoric humans were, or how they remained connected. Maintaining social cohesion was crucial for early humans because social networks facilitate cooperation and are imperative for survival and reproduction. Recent hunter-gatherer social organisation typically comprises a number of nested layers, ranging from the nuclear family through to the ~1500-strong ethnolinguistic tribe. Here we compare maximum obsidian transfer distances from the late Pleistocene with ethnographic data on the size of the geographic areas associated with each of these social grouping layers in recent hunter-gatherers. The closest match between the two is taken to indicate the maximum social layer within which contact could be sustained by Pleistocene hominins. Within both the (sub)tropical African and Subarctic biomes, the maximum obsidian transfer distances for Pleistocene modern humans (~200km and ~400km respectively) correspond to the geographic ranges of the outermost tribal layer in recent hunter-gatherers. This suggests that modern humans could potentially sustain the cohesion of their entire tribe at all latitudes, even though networks are more dispersed nearer the poles. Neanderthal obsidian transfer distances (300km) indicate that although Neanderthal home ranges are larger than those of low latitude hominins, Neanderthals travelled shorter distances than modern humans living at the same high latitudes. We argue that, like modern humans, Neanderthals could have maintained tribal cohesion, but that their tribes were substantially smaller than those of contemporary modern humans living in similar environments. The greater time taken to traverse the larger modern human tribal ranges may have limited the frequency of their face-to-face interactions and thus necessitated additional mechanisms to ensure network connectivity, such as the exchange of symbolic artefacts including ornaments and figurines. Such cultural supports may not have been required to the same extent by the Neanderthals due to their smaller tribes and home ranges.
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Affiliation(s)
- Eiluned Pearce
- Social and Evolutionary Neuroscience Research Group, Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK
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43
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Chapais B. Complex Kinship Patterns as Evolutionary Constructions, and the Origins of Sociocultural Universals. CURRENT ANTHROPOLOGY 2014. [DOI: 10.1086/678972] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Fine-scale genetic assessment of sex-specific dispersal patterns in a multilevel primate society. J Hum Evol 2014; 78:103-13. [PMID: 25466516 DOI: 10.1016/j.jhevol.2014.10.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 10/29/2014] [Accepted: 10/30/2014] [Indexed: 11/23/2022]
Abstract
Like humans, hamadryas baboons (Papio hamadryas) are unusual among primates in having a multilevel social system and stable pair bonds, and are thus a useful model for the evolution of human sociality. While the kinship structure and sex-biased dispersal patterns that underlie human social organization have been extensively elucidated, the impact of these factors on the social system of hamadryas baboons is currently unclear. Here we use genetic analysis of individuals to elucidate the patterns of male and female dispersal across multiple levels of society in a wild population of hamadryas baboons. We characterized 244 members of five hamadryas bands at Filoha, Ethiopia by genotyping one Y-linked and 23 autosomal microsatellite loci and sequencing part of the mitochondrial hypervariable control region I. We found both male and female dispersal to be limited at the level of the band, with more movement of females than males among bands. By integrating long-term behavioral data for Band 1, we also found evidence for male and female philopatry at the clan level. We speculate that male philopatry at the clan level and female dispersal across one-male units and clans may enable both kin-based cooperation among males and the maintenance of kin bonds among females after dispersal. This would mean that, as in humans, kin bonds within both sexes are a core feature of the hamadryas social system, thus contributing to our understanding of the evolution of social organization in humans.
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Pearce E. Modelling mechanisms of social network maintenance in hunter-gatherers. JOURNAL OF ARCHAEOLOGICAL SCIENCE 2014; 50:403-413. [PMID: 25214706 PMCID: PMC4157219 DOI: 10.1016/j.jas.2014.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Due to decreasing resource densities, higher latitude hunter-gatherers need to maintain their social networks over greater geographic distances than their equatorial counterparts. This suggests that as latitude increases, the frequency of face-to-face interaction decreases for 'weak tie' relationships in the outer mating pool (~500-strong) and tribal (~1500-strong) layers of a hunter-gatherer social network. A key question, then, is how a hunter-gatherer tribe sustains coherence as a single identifiable unit given that members are distributed across a large geographic area. The first step in answering this question is to establish whether the expectation that network maintenance raises a challenge for hunter-gatherers is correct, or whether sustaining inter-group contact is in fact trivial. Here I present a null model that represents mobile groups as randomly and independently moving gas particles. The aim of this model is to examine whether face-to-face contact can be maintained with every member of an individual's tribe at all latitudes even under the baseline assumption of random movement. Contrary to baseline expectations, the number of encounters between groups predicted by the gas model cannot support tribal cohesion and is significantly negatively associated with absolute latitude. In addition, above ~40 degrees latitude random mobility no longer produces a sufficient number of encounters between groups to maintain contact across the 500-strong mating pool. These model predictions suggest that the outermost layers of hunter-gatherers' social networks may require additional mechanisms of support in the form of strategies that either enhance encounter rates, such as coordinated mobility patterns, or lessen the need for face-to-face interaction, such as the use of symbolic artefacts to represent social affiliations. Given the predicted decline in encounters away from the equator, such additional supports might be most strongly expressed at high latitudes.
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Affiliation(s)
- Eiluned Pearce
- Social and Evolutionary Neuroscience Research Group, Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK, +441865 271 367,
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Chapais B. Monogamy, strongly bonded groups, and the evolution of human social structure. Evol Anthropol 2013; 22:52-65. [PMID: 23585378 DOI: 10.1002/evan.21345] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Human social evolution has most often been treated in a piecemeal fashion, with studies focusing on the evolution of specific components of human society such as pair-bonding, cooperative hunting, male provisioning, grandmothering, cooperative breeding, food sharing, male competition, male violence, sexual coercion, territoriality, and between-group conflicts. Evolutionary models about any one of those components are usually concerned with two categories of questions, one relating to the origins of the component and the other to its impact on the evolution of human cognition and social life. Remarkably few studies have been concerned with the evolution of the entity that integrates all components, the human social system itself. That social system has as its core feature human social structure, which I define here as the common denominator of all human societies in terms of group composition, mating system, residence patterns, and kinship structures. The paucity of information on the evolution of human social structure poses substantial problems because that information is useful, if not essential, to assess both the origins and impact of any particular aspect of human society.
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Grueter CC, Chapais B, Zinner D. Evolution of Multilevel Social Systems in Nonhuman Primates and Humans. INT J PRIMATOL 2012; 33:1002-1037. [PMID: 23024444 PMCID: PMC3456960 DOI: 10.1007/s10764-012-9618-z] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 04/26/2012] [Indexed: 01/19/2023]
Abstract
Multilevel (or modular) societies are a distinct type of primate social system whose key features are single-male-multifemale, core units nested within larger social bands. They are not equivalent to fission-fusion societies, with the latter referring to routine variability in associations, either on an individual or subunit level. The purpose of this review is to characterize and operationalize multilevel societies and to outline their putative evolutionary origins. Multilevel societies are prevalent in three primate clades: papionins, Asian colobines, and hominins. For each clade, we portray the most parsimonious phylogenetic pathway leading to a modular system and then review and discuss likely socioecological conditions promoting the establishment and maintenance of these societies. The multilevel system in colobines (most notably Rhinopithecus and Nasalis) has likely evolved as single-male harem systems coalesced, whereas the multilevel system of papionins (Papio hamadryas, Theropithecus gelada) and hominins most likely arose as multimale-multifemale groups split into smaller units. We hypothesize that, although ecological conditions acted as preconditions for the origin of multilevel systems in all three clades, a potentially important catalyst was intraspecific social threat, predominantly bachelor threat in colobines and female coercion/infanticide in papionins and humans. We emphasize that female transfers within bands or genetic relationships among leader males help to maintain modular societies by facilitating interunit tolerance. We still lack a good or even basic understanding of many facets of multilevel sociality. Key remaining questions are how the genetic structure of a multilevel society matches the observed social effort of its members, to what degree cooperation of males of different units is manifest and contributes to band cohesion, and how group coordination, communication, and decision making are achieved. Affiliative and cooperative interunit relations are a hallmark of human societies, and studying the precursors of intergroup pacification in other multilevel primates may provide insights into the evolution of human uniqueness.
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Affiliation(s)
- Cyril C. Grueter
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA 6009 Australia
- Anthropological Institute and Museum, University of Zürich-Irchel, CH-8057 Zürich, Switzerland
| | - Bernard Chapais
- Department of Anthropology, University of Montreal, Montréal, Quebec H3C 3 J7 Canada
| | - Dietmar Zinner
- Cognitive Ethology Laboratory, German Primate Center (DPZ), 37077 Göttingen, Germany
- Courant Research Centre “Evolution of Social Behavior”, University of Göttingen, 37077 Göttingen, Germany
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Grueter CC, Matsuda I, Zhang P, Zinner D. Multilevel Societies in Primates and Other Mammals: Introduction to the Special Issue. INT J PRIMATOL 2012; 33:993-1001. [PMID: 23024443 PMCID: PMC3456921 DOI: 10.1007/s10764-012-9614-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 04/07/2012] [Indexed: 01/07/2023]
Affiliation(s)
- Cyril C. Grueter
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA 6009 Australia
- Anthropological Institute and Museum, University of Zürich-Irchel, 8057 Zürich, Switzerland
| | - Ikki Matsuda
- Primate Research Institute, Kyoto University, Inuyama, 484-8506 Japan
| | - Peng Zhang
- Anthropology Department, Sun Yat-sen University, Guangzhou, 510275 China
| | - Dietmar Zinner
- Cognitive Ethology Laboratory, German Primate Center, 37077 Göttingen, Germany
- Courant Research Centre “Evolution of Social Behavior”, University of Göttingen, 37077 Göttingen, Germany
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