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Friant S. Human behaviors driving disease emergence. Evol Anthropol 2024; 33:e22015. [PMID: 38130075 DOI: 10.1002/evan.22015] [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: 07/18/2023] [Revised: 10/26/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023]
Abstract
Interactions between humans, animals, and the environment facilitate zoonotic spillover-the transmission of pathogens from animals to humans. Narratives that cast modern humans as exogenous and disruptive forces that encroach upon "natural" disease systems limit our understanding of human drivers of disease. This review leverages theory from evolutionary anthropology that situates humans as functional components of disease ecologies, to argue that human adaptive strategies to resource acquisition shape predictable patterns of high-risk human-animal interactions, (2) humans construct ecological processes that facilitate spillover, and (3) contemporary patterns of epidemiological risk are emergent properties of interactions between human foraging ecology and niche construction. In turn, disease ecology serves as an important vehicle to link what some cast as opposing bodies of theory in human ecology. Disease control measures should consider human drivers of disease as rational, adaptive, and dynamic and capitalize on our capacity to influence ecological processes to mitigate risk.
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Affiliation(s)
- Sagan Friant
- Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania, USA
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
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2
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Hawkes K. Life history impacts on infancy and the evolution of human social cognition. Front Psychol 2023; 14:1197378. [PMID: 38023007 PMCID: PMC10666779 DOI: 10.3389/fpsyg.2023.1197378] [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: 03/31/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023] Open
Abstract
Greater longevity, slower maturation and shorter birth intervals are life history features that distinguish humans from the other living members of our hominid family, the great apes. Theory and evidence synthesized here suggest the evolution of those features can explain both our bigger brains and our cooperative sociality. I rely on Sarah Hrdy's hypothesis that survival challenges for ancestral infants propelled the evolution of distinctly human socioemotional appetites and Barbara Finlay and colleagues' findings that mammalian brain size is determined by developmental duration. Similar responsiveness to varying developmental contexts in chimpanzee and human one-year-olds suggests similar infant responsiveness in our nearest common ancestor. Those ancestral infants likely began to acquire solid food while still nursing and fed themselves at weaning as chimpanzees and other great apes do now. When human ancestors colonized habitats lacking foods that infants could handle, dependents' survival became contingent on subsidies. Competition to engage subsidizers selected for capacities and tendencies to enlist and maintain social connections during the early wiring of expanding infant brains with lifelong consequences that Hrdy labeled "emotionally modern" social cognition.
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Affiliation(s)
- Kristen Hawkes
- Department of Anthropology, College of Social and Behavioral Science, University of Utah, Salt Lake City, UT, United States
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3
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Anurag A, Sharma S. An evolutionary explanation for increased cesarean section rates. MGM JOURNAL OF MEDICAL SCIENCES 2023. [DOI: 10.4103/mgmj.mgmj_168_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023] Open
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4
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A cost for signaling: do Hadza hunter-gatherers forgo calories to show-off in an experimental context? EVOL HUM BEHAV 2022. [DOI: 10.1016/j.evolhumbehav.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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Reynolds TA. Response to Commentaries: Variation in Women's Intrasexual Sociality by Life History Strategy, Patrilocal Legacy, and Polygyny. ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:3299-3310. [PMID: 35854162 DOI: 10.1007/s10508-022-02378-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Tania A Reynolds
- Department of Psychology, University of New Mexico, Logan Hall, MSC03-2220, Albuquerque, NM, 87131-0001, USA.
- The Kinsey Institute, Indiana University, Bloomington, USA.
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6
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Benenson JF. The Overloaded Mother. ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:3257-3262. [PMID: 33768476 DOI: 10.1007/s10508-021-01983-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/02/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Joyce F Benenson
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA, 02138, USA.
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7
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Somatic maintenance/reproduction tradeoffs and human evolution. Behav Brain Sci 2022; 45:e138. [PMID: 35875957 DOI: 10.1017/s0140525x22000474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The authors propose that many morbidities higher in women than men are adaptations protecting survival, selected because survival has been especially crucial to mothers' reproductive success. Following their lead, I pursue variation in tradeoffs between reproduction and survival recognized by Darwin that were likely central to the evolution of many traits that distinguish us from our great ape cousins.
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8
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Crespi BJ, Flinn MV, Summers K. Runaway Social Selection in Human Evolution. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.894506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Darwin posited that social competition among conspecifics could be a powerful selective pressure. Alexander proposed a model of human evolution involving a runaway process of social competition based on Darwin’s insight. Here we briefly review Alexander’s logic, and then expand upon his model by elucidating six core arenas of social selection that involve runaway, positive-feedback processes, and that were likely involved in the evolution of the remarkable combination of adaptations in humans. We discuss how these ideas fit with the hypothesis that a key life history innovation that opened the door to runaway social selection, and cumulative culture, during hominin evolution was increased cooperation among individuals in small fission-fusion groups.
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Human Females as a Dispersal-Egalitarian Species: A Hypothesis about Women and Status. ADAPTIVE HUMAN BEHAVIOR AND PHYSIOLOGY 2022. [DOI: 10.1007/s40750-022-00191-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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10
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Le A, Hawkes K, Kim PS. Male mating choices: The drive behind menopause? Theor Popul Biol 2022; 145:126-135. [PMID: 35525440 DOI: 10.1016/j.tpb.2022.04.001] [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: 09/30/2021] [Revised: 01/29/2022] [Accepted: 04/24/2022] [Indexed: 11/28/2022]
Abstract
When we examine the life history of humans against our closest primate relatives, the other great apes, there is notably a greater longevity in humans which includes a distinctive postmenopausal life stage, leading to the question, "How did human females evolve to have old-age infertility?" In their paper "Mate choice and the origin of menopause" (Morton et al., 2013), Morton et al. developed an agent-based model (ABM) to investigate the novel hypothesis that ancestral male mating choices, particularly forgoing mating with older females, was the driving force behind the evolution of menopause. From their model, they concluded that indeed male preference for young female mates could have driven females to lose fertility at older ages through deleterious mutations, leading to menopause. In this work, we revisit their male-mate-choice hypothesis by formulating an analogous mathematical model using a system of ordinary differential equations (ODEs). We first show that our ODE model recreates the qualitative behaviour and hence conclusions of key scenarios in Morton et al. (2013). However, since our ODE system is less computationally demanding than their ABM, we also conduct a broader sensitivity analysis over a range of parameters and differing initial conditions to analyse the dependence on their conclusions to underlying assumptions. Our results challenge those of Morton et al. as we find that even the slightest deviation from an exclusive mating preference for younger females would counteract the evolution of menopause. Consequently, we propose that their male-mate-choice hypothesis is incomplete and needs further explanation of how a male strategy to exclusively mate with young females could have arisen in our common ancestors and remained evolutionary stable for long enough to drive the evolution of old-age female infertility.
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Affiliation(s)
- Anthia Le
- School of Mathematics and Physics, The University of Queensland, Brisbane, Australia.
| | - Kristen Hawkes
- Department of Anthropology, University of Utah, Salt Lake City, USA
| | - Peter S Kim
- School of Mathematics and Statistics, The University of Sydney, Sydney, Australia
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11
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Lobo J, Whitelaw T, Bettencourt LMA, Wiessner P, Smith ME, Ortman S. Scaling of Hunter-Gatherer Camp Size and Human Sociality. CURRENT ANTHROPOLOGY 2022. [DOI: 10.1086/719234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Stibbard-Hawkes DN, Smith K, Apicella CL. Why hunt? Why gather? Why share? Hadza assessments of foraging and food-sharing motive. EVOL HUM BEHAV 2022. [DOI: 10.1016/j.evolhumbehav.2022.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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13
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Aoki K, Wakano JY. Hominin forager technology, food sharing, and diet breadth. Theor Popul Biol 2022; 144:37-48. [DOI: 10.1016/j.tpb.2022.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 11/25/2022]
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14
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Gallois S, Henry AG. The Cost of Gathering Among the Baka Forager-Horticulturalists From Southeastern Cameroon. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.768003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
What present-day foragers do for their living and what they eat have long been privileged areas for exploring human behavior, global health, and human evolution. While many studies have focused on hunting and meat acquisition, less attention has been given to gathering and plant foods. Despite evidence of variation in both nutritional quality and energetic costs of gathering different plants, the overall effort spent on gathering in relation to other subsistence tasks is still under explored. In the current context of economic, climate, and social changes, many forager societies also rely on other subsistence strategies, including agriculture and wage labor. In this study, we aim to explore the place of gathering in the livelihood of a mixed economy society, the Baka forager-horticulturalists of southeastern Cameroon, by comparing the involvement and the costs of activities related to food acquisition. From a pool of 153 adult participants (97 women and 56 men), we collected 246 daily records using a GPS (Global Positioning System) tracker combined with heart rate monitor and time allocation recalls. We compared the duration, distance traveled, and the intensity of work, measured by calculating the metabolic equivalent of task (MET), of subsistence activities related to food acquisition. Results from this work show that gathering activities, performed by both women and men, are energetically costly, with higher MET values than hunting and fishing activities. Furthermore, the MET values vary depending on the targeted plant foods. We discuss these insights in the overall framework of subsistence patterns, merging them with the socio-cultural and environmental factors that might explain Baka livelihood and subsistence strategy.
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Abstract
Many male traits are well explained by sexual selection theory as adaptations to mating competition and mate choice, whereas no unifying theory explains traits expressed more in females. Anne Campbell's "staying alive" theory proposed that human females produce stronger self-protective reactions than males to aggressive threats because self-protection tends to have higher fitness value for females than males. We examined whether Campbell's theory has more general applicability by considering whether human females respond with greater self-protectiveness than males to other threats beyond aggression. We searched the literature for physiological, behavioral, and emotional responses to major physical and social threats, and found consistent support for females' responding with greater self-protectiveness than males. Females mount stronger immune responses to many pathogens; experience a lower threshold to detect, and lesser tolerance of, pain; awaken more frequently at night; express greater concern about physically dangerous stimuli; exert more effort to avoid social conflicts; exhibit a personality style more focused on life's dangers; react to threats with greater fear, disgust and sadness; and develop more threat-based clinical conditions than males. Our findings suggest that in relation to threat human females have relatively heightened protective reactions compared to males. The pervasiveness of this result across multiple domains suggests that general mechanisms might exist underlying females' unique adaptations. An understanding of such processes would enhance knowledge of female health and well-being.
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16
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Seasonality and Oldowan behavioral variability in East Africa. J Hum Evol 2021; 164:103070. [PMID: 34548178 DOI: 10.1016/j.jhevol.2021.103070] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 10/20/2022]
Abstract
The extent, nature, and temporality of early hominin food procurement strategies have been subject to extensive debate. In this article, we examine evidence for the seasonal scheduling of resource procurement and technological investment in the Oldowan, starting with an evaluation of the seasonal signature of underground storage organs, freshwater resources, and terrestrial animal resources in extant primates and modern human hunter-gatherer populations. Subsequently, we use the mortality profiles, taxonomic composition, and taphonomy of the bovid assemblages at Kanjera South (Homa Peninsula, Kenya) and FLK-Zinj (Olduvai Gorge, Tanzania) to illustrate the behavioral flexibility of Oldowan hominins, who were targeting different seasonally vulnerable demographics. In terms of the lithic assemblages, the specific opportunities and constraints afforded by dry season subsistence at FLK-Zinj may have disincentivized lithic investment, resulting in a more expedient toolkit for fast and effective carcass processing. This may have been reinforced by raw material site provisioning during a relatively prolonged seasonal occupation, reducing pressures on the reduction and curation of lithic implements. In contrast, wet season plant abundance would have offered a predictable set of high-quality resources associated with low levels of competition and reduced search times, in the context of perhaps greater seasonal mobility and consequently shorter occupations. These factors appear to have fostered technological investment to reduce resource handling costs at Kanjera South, facilitated by more consistent net returns and enhanced planning of lithic deployment throughout the landscape. We subsequently discuss the seasonality of freshwater resources in Oldowan procurement strategies, focusing on FwJj20 (Koobi Fora, Kenya). Although more analytical studies with representative sample sizes are needed, we argue that interassemblage differences evidence the ability of Oldowan hominins to adapt to seasonal constraints and opportunities in resource exploitation.
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17
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Watkins A. Reevaluating the grandmother hypothesis. HISTORY AND PHILOSOPHY OF THE LIFE SCIENCES 2021; 43:103. [PMID: 34427800 DOI: 10.1007/s40656-021-00455-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Menopause is an evolutionary mystery: how could living longer with no capacity to reproduce possibly be advantageous? Several explanations have been offered for why female humans, unlike our closest primate relatives, have such an extensive post-reproductive lifespan. Proponents of the so-called "grandmother hypothesis" suggest that older women are able to increase their fitness by helping to care for their grandchildren as allomothers. This paper first distinguishes the grandmother hypothesis from several other hypotheses that attempt to explain menopause, and then develops a formal model by which these hypotheses can be compared and tested by empirical researchers. The model is then modified and used to respond to a common objection to the grandmother hypothesis: that human fathers, rather than grandmothers, are better suited to be allomothers due to their physical strength and a high incentive to invest in their own children. However, fathers-unlike maternal grandmothers-can never be sure that the children they are caring for are their own. Incorporating paternity uncertainty into the model demonstrates the conditions under which the grandmother hypothesis is more plausible than a hypothesis that focuses on the contributions of men.
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Affiliation(s)
- Aja Watkins
- Philosophy Department, Boston University, Boston, MA, USA.
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18
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Gravel-Miguel C, Murray JK, Schoville BJ, Wren CD, Marean CW. Exploring variability in lithic armature discard in the archaeological record. J Hum Evol 2021; 155:102981. [PMID: 33848696 DOI: 10.1016/j.jhevol.2021.102981] [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: 08/25/2020] [Revised: 02/23/2021] [Accepted: 02/23/2021] [Indexed: 11/28/2022]
Abstract
The invention of projectile technology had important ramifications for hominin evolution. However, the number of stone points that could have been used as projectiles fluctuates in archaeological assemblages, making it difficult to define when projectile technology was first widely adopted and how its usage changed over time. Here we use an agent-based model to simulate a hunter-gatherer foraging system where armatures are dropped according to their usage. We explore the impact of interactions between human behaviors and the environmental constraints of a data-informed landscape on the distribution and number of lithic armatures found in archaeological assemblages. We ran 2400 simulations modeling different population sizes, rates of hunting with projectiles, and tool curation levels. For each simulation, we recorded the location of dropped armatures and calculated the number and percentage of used armatures that were discarded at habitation camps vs. lost during hunting. We used linear regression to identify the demographic, behavioral, and environmental factor(s) that best explained changes in these numbers and percentages. The model results show that in a well-controlled environment, most armatures used as projectile weapons are lost or discarded at hunting sites; only ∼4.5% of used armatures (or ∼2 armatures per year of simulation) are discarded in habitation camps where they would likely be excavated. These findings suggest that even rare hafted armatures found in the Early and Middle Stone Age could indicate a well-established use of such tools. Our model shows that interactions between reoccupation of archaeological sites, population size, rate of hunting with projectile weapons, and tool curation levels strongly influence the count of lithic armatures found in archaeological assemblages. Therefore, we argue that fluctuations in the counts of armatures documented at archaeological sites should be evaluated within their demographic and environmental contexts to better understand if they reflect spatiotemporal changes in hunting behavior.
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Affiliation(s)
- Claudine Gravel-Miguel
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA; Département d'anthropologie, Université de Montréal, Montréal, QC, Canada.
| | - John K Murray
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA
| | - Benjamin J Schoville
- School of Social Science, Faculty of Humanities and Social Sciences, The University of Queensland, St Lucia, Australia
| | - Colin D Wren
- Department of Anthropology, University of Colorado, Colorado Springs, CO, USA
| | - Curtis W Marean
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA; African Centre for Coastal Palaeoscience, Nelson Mandela University, Eastern Cape, South Africa
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19
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Yegian AK, Tucker Y, Gillinov S, Lieberman DE. Shorter distal forelimbs benefit bipedal walking and running mechanics: Implications for hominin forelimb evolution. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 175:589-598. [PMID: 33818760 DOI: 10.1002/ajpa.24274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 02/10/2021] [Accepted: 03/07/2021] [Indexed: 11/07/2022]
Abstract
OBJECTIVES Brachial index is a skeletal ratio that describes the relative length of the distal forelimb. Over the course of hominin evolution, a shift toward smaller brachial indices occurred. First, Pleistocene australopiths yield values between extant chimpanzees and humans, with further evolution in Pliocene Homo to the modern human range. We hypothesized that shorter distal forelimbs benefit walking and running performance, notably elbow and shoulder joint torques, and predicted that the benefit would be greater in running compared to walking. MATERIALS AND METHODS We tested our hypothesis in a modern human sample walking and running while carrying hand weights, which increase the inertia (mass and effective length) of the distal forelimb, simulating a larger brachial index. RESULTS We found longer distal forelimbs and the added mass increased elbow muscle torque by 98% while walking and 70% in running, confirming our hypothesis that shorter distal forelimbs benefit walking and running performance. Shoulder muscle torque similarly increased in both gaits with the addition of hand weights due to elongation of the effective forelimb length. Normalized elbow torque, which accounted for the effect on shoulder torque caused by the experimental manipulation, increased by 16% while walking but 52% while running, indicating that shorter distal forelimbs provide a greater benefit for running by approximately three-fold. DISCUSSION Selection for economical bipedal walking in Australopithecus and endurance running in Homo likely contributed to the shift toward relatively smaller distal forelimbs across hominin evolution, with modern human proportions attained in Pleistocene Homo erectus and retained in later species.
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Affiliation(s)
- Andrew K Yegian
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Yanish Tucker
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA.,School of Clinical Medicine, University of Cambridge, Cambridge, England
| | - Stephen Gillinov
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Daniel E Lieberman
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
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20
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Ben-Dor M, Sirtoli R, Barkai R. The evolution of the human trophic level during the Pleistocene. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 175 Suppl 72:27-56. [PMID: 33675083 DOI: 10.1002/ajpa.24247] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/07/2020] [Accepted: 01/19/2021] [Indexed: 02/06/2023]
Abstract
The human trophic level (HTL) during the Pleistocene and its degree of variability serve, explicitly or tacitly, as the basis of many explanations for human evolution, behavior, and culture. Previous attempts to reconstruct the HTL have relied heavily on an analogy with recent hunter-gatherer groups' diets. In addition to technological differences, recent findings of substantial ecological differences between the Pleistocene and the Anthropocene cast doubt regarding that analogy's validity. Surprisingly little systematic evolution-guided evidence served to reconstruct HTL. Here, we reconstruct the HTL during the Pleistocene by reviewing evidence for the impact of the HTL on the biological, ecological, and behavioral systems derived from various existing studies. We adapt a paleobiological and paleoecological approach, including evidence from human physiology and genetics, archaeology, paleontology, and zoology, and identified 25 sources of evidence in total. The evidence shows that the trophic level of the Homo lineage that most probably led to modern humans evolved from a low base to a high, carnivorous position during the Pleistocene, beginning with Homo habilis and peaking in Homo erectus. A reversal of that trend appears in the Upper Paleolithic, strengthening in the Mesolithic/Epipaleolithic and Neolithic, and culminating with the advent of agriculture. We conclude that it is possible to reach a credible reconstruction of the HTL without relying on a simple analogy with recent hunter-gatherers' diets. The memory of an adaptation to a trophic level that is embedded in modern humans' biology in the form of genetics, metabolism, and morphology is a fruitful line of investigation of past HTLs, whose potential we have only started to explore.
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Affiliation(s)
- Miki Ben-Dor
- Department of Archaeology, Tel Aviv University, Tel Aviv, Israel
| | | | - Ran Barkai
- Department of Archaeology, Tel Aviv University, Tel Aviv, Israel
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21
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Stibbard-Hawkes DNE, Attenborough RD. Some omissions, few confusions. A reply to Pinheiro 2021. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 174:392-395. [PMID: 33417717 DOI: 10.1002/ajpa.24223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 12/20/2020] [Indexed: 11/05/2022]
Affiliation(s)
| | - Robert D Attenborough
- Department of Archaeology and Anthropology, University of Cambridge, Cambridge, UK.,School of Archaeology and Anthropology, The Australian National University, Canberra, Australia
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22
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French JC, Chamberlain AT. Demographic uniformitarianism: the theoretical basis of prehistoric demographic research and its cross-disciplinary challenges. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190720. [PMID: 33250031 DOI: 10.1098/rstb.2019.0720] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A principle of demographic uniformitarianism underpins all research into prehistoric demography (palaeodemography). This principle-which argues for continuity in the evolved mechanisms underlying modern human demographic processes and their response to environmental stimuli between past and present-provides the cross-disciplinary basis for palaeodemographic reconstruction and analysis. Prompted by the recent growth and interest in the field of prehistoric demography, this paper reviews the principle of demographic uniformitarianism, evaluates how it relates to two key debates in palaeodemographic research and seeks to delimit its range of applicability to past human and hominin populations. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.
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Affiliation(s)
- Jennifer C French
- Department of Archaeology, Classics, and Egyptology, University of Liverpool, 12-14 Abercromby Square, L69 7WZ, UK
| | - Andrew T Chamberlain
- Department of Earth and Environmental Sciences, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK
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23
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Hawkes K. The Centrality of Ancestral Grandmothering in Human Evolution. Integr Comp Biol 2020; 60:765-781. [PMID: 32386309 DOI: 10.1093/icb/icaa029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
When Fisher, Williams, and Hamilton laid the foundations of evolutionary life history theory, they recognized elements of what became a grandmother hypothesis to explain the evolution of human postmenopausal longevity. Subsequent study of modern hunter-gatherers, great apes, and the wider mammalian radiation has revealed strong regularities in development and behavior that show additional unexpected consequences that ancestral grandmothering likely had on human evolution, challenging the hypothesis that ancestral males propelled the evolution of our radiation by hunting to provision mates and offspring. Ancestral grandmothering has become a serious contender to explain not only the large fraction of post-fertile years women live and children's prolonged maturation yet early weaning; it also promises to help account for the pair bonding that distinguishes humans from our closest living evolutionary cousins, the great apes (and most other mammals), the evolution of our big human brains, and our distinctive preoccupation with reputations, shared intentionality and persistent cultural learning that begins in infancy.
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Affiliation(s)
- Kristen Hawkes
- Anthropology, University of Utah, 260 South Central Campus Drive, Gardener Commons Suite 4625, Salt Lake City, UT 84112, USA
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24
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Crockford C, Samuni L, Vigilant L, Wittig RM. Postweaning maternal care increases male chimpanzee reproductive success. SCIENCE ADVANCES 2020; 6:6/38/eaaz5746. [PMID: 32948598 PMCID: PMC7500924 DOI: 10.1126/sciadv.aaz5746] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 07/28/2020] [Indexed: 06/01/2023]
Abstract
Humans are unusual among animals for continuing to provision and care for their offspring until adulthood. This "prolonged dependency" is considered key for the evolution of other notable human traits, such as large brains, complex societies, and extended postreproductive lifespans. Prolonged dependency must therefore have evolved under conditions in which reproductive success is gained with parental investment and diminished with early parental loss. We tested this idea using data from wild chimpanzees, which have similarly extended immature years as humans and prolonged mother-offspring associations. Males who lost their mothers after weaning but before maturity began reproducing later and had lower average reproductive success. Thus, persistent mother-immature son associations seem vital for enhancing male reproductive success, although mothers barely provision sons after weaning. We posit that these associations lead to social gains, crucial for successful reproduction in complex social societies, and offer insights into the evolution of prolonged dependency.
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Affiliation(s)
- Catherine Crockford
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
- Taï Chimpanzee Project, CSRS, Abidjan, Ivory Coast
- Human Behaviour, Ecology & Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Liran Samuni
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Taï Chimpanzee Project, CSRS, Abidjan, Ivory Coast
- Department of Human Evolutionary Biology, Harvard University, Cambridge, USA
| | - Linda Vigilant
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Roman M Wittig
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Taï Chimpanzee Project, CSRS, Abidjan, Ivory Coast
- Human Behaviour, Ecology & Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Hawkes K. Cognitive consequences of our grandmothering life history: cultural learning begins in infancy. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190501. [PMID: 32475323 PMCID: PMC7293154 DOI: 10.1098/rstb.2019.0501] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2020] [Indexed: 11/12/2022] Open
Abstract
Postmenopausal longevity distinguishes humans from our closest living evolutionary cousins, the great apes, and may have evolved in our lineage when the economic productivity of grandmothers allowed mothers to wean earlier and overlap dependents. Since increased longevity retards development and expands brain size across the mammals, this hypothesis links our slower developing, bigger brains to ancestral grandmothering. If foraging interdependence favoured postmenopausal longevity because grandmothers' subsidies reduced weaning ages, then ancestral infants lost full maternal engagement while their slower developing brains were notably immature. With survival dependent on social relationships, sensitivity to reputations is wired very early in neural ontogeny, beginning our lifelong preoccupation with shared intentionality. 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)
- Kristen Hawkes
- Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA
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Sarma MS, Boyette AH, Lew-Levy S, Miegakanda V, Kilius E, Samson DR, Gettler LT. Sex differences in daily activity intensity and energy expenditure and their relationship to cortisol among BaYaka foragers from the Congo Basin. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 172:423-437. [PMID: 32441329 DOI: 10.1002/ajpa.24075] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVES The pooling of energetic resources and food sharing have been widely documented among hunter-gatherer societies. Much less is known about how the energetic costs of daily activities are distributed across individuals in such groups, including between women and men. Moreover, the metabolic physiological correlates of those activities and costs are relatively understudied. MATERIALS AND METHODS Here, we tracked physical activity, energy expenditure (EE), and cortisol production among Congo Basin BaYaka foragers engaged in a variety of daily subsistence activities (n = 37). Given its role in energy mobilization, we measured overall daily cortisol production and short-term cortisol reactivity through saliva sampling; we measured physical activity levels and total EE via the wGT3X-bt actigraph and heart rate monitor. RESULTS We found that there were no sex differences in likelihood of working in common activity locations (forest, garden, house). Across the day, women spent greater percentage time in moderate-to-vigorous physical activity (%MVPA) and had lower total EE than men. Females with higher EE (kCal/hr) produced greater cortisol throughout the day. Though not statistically significant, we also found that individuals with greater %MVPA had larger decreases in cortisol reactivity. DISCUSSION BaYaka women sustained higher levels of physical activity but incurred lower energetic costs than men, even after factoring in sex differences in body composition. Our findings suggest that the distribution of physical activity demands and costs are relevant to discussions regarding how labor is divided and community energy budgets take shape in such settings.
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Affiliation(s)
- Mallika S Sarma
- Department of Anthropology, University of Notre Dame, Notre Dame, Indiana, USA
| | - Adam H Boyette
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Sheina Lew-Levy
- Department of Psychology, Simon Fraser University, Burnaby, Canada.,Department of Archeology and Heritage Studies, Aarhus University, Aarhus, Denmark
| | - Valchy Miegakanda
- Institut National de Santé Publique, Brazzaville, Republic of the Congo
| | - Erica Kilius
- Department of Anthropology, University of Toronto Mississauga, Mississauga, Canada
| | - David R Samson
- Department of Anthropology, University of Toronto Mississauga, Mississauga, Canada
| | - Lee T Gettler
- Department of Anthropology, University of Notre Dame, Notre Dame, Indiana, USA.,The Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
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Stibbard‐Hawkes DNE, Attenborough RD, Mabulla IA, Marlowe FW. To the hunter go the spoils? No evidence of nutritional benefit to being or marrying a well‐reputed Hadza hunter. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 173:61-79. [DOI: 10.1002/ajpa.24027] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/16/2020] [Accepted: 02/10/2020] [Indexed: 11/07/2022]
Affiliation(s)
| | - Robert D. Attenborough
- Department of Archaeology and AnthropologyCambridge University Cambridge UK
- School of Archaeology and AnthropologyThe Australian National University Canberra Australia
| | - Ibrahim A. Mabulla
- Institute of Resource AssessmentUniversity of Dar es Salaam Dar es Salaam Tanzania
| | - Frank W. Marlowe
- Department of Archaeology and AnthropologyCambridge University Cambridge UK
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Stibbard-Hawkes DNE. No Association between 2D:4D Ratio and Hunting Success among Hadza Hunters. HUMAN NATURE (HAWTHORNE, N.Y.) 2020; 31:22-42. [PMID: 31838723 DOI: 10.1007/s12110-019-09359-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The ratio of index- and ring-finger lengths (2D:4D ratio) is thought to be related to prenatal androgen exposure, and in many, though not all, populations, men have a lower average digit ratio than do women. In many studies an inverse relationship has been observed, among both men and women, between 2D:4D ratio and measures of athletic ability. It has been further suggested that, in hunter-gatherer populations, 2D:4D ratio might also be negatively correlated with hunting ability, itself assumed to be contingent on athleticism. This hypothesis has been tested using endurance running performance among runners from a Western, educated, and industrialized population as a proximate measure of hunting ability. However, it has not previously been tested among actual hunter-gatherers using more ecologically valid measures of hunting ability and success. The current study addresses this question among Tanzanian Hadza hunter-gatherers. I employ a novel method of assessing hunting reputation that, unlike previous methods, allows granular distinctions to be made between hunters at all levels of perceived ability. I find no statistically significant relationship between digit ratio and either hunting reputation or two important hunting skills. I confirm that Hadza men have higher mean 2D:4D ratios than men in many Western populations. I discuss the notion that 2D:4D ratio may be the consequence of an allometric scaling relationship between relative and absolute finger lengths. Although it is difficult to draw clear conclusions from these results, the current study provides no support for the theorized relationship between 2D:4D ratio and hunting skill.
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Prado-Nóvoa O, Rodríguez J, Vidal-Cordasco M, Zorrilla-Revilla G, Mateos A. No sex differences in the economy of load-carriage. Am J Hum Biol 2019; 32:e23352. [PMID: 31675143 DOI: 10.1002/ajhb.23352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 08/09/2019] [Accepted: 09/30/2019] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVES Load transport activities are of vital importance to current foragers for daily subsistence tasks; thus, it has been suggested that these practices have transformed physical and behavioral characteristics through human evolution. Together with the procurement targets and strategies, the transportation of resources acquired while foraging is strongly influenced by the sex of the foragers. In hunter-gatherer societies, women, despite their smaller body size, usually carry heavier burdens than males. In this study, whether those behavioral differences can be explained by a different economy of load-carriage by sex, irrespective of the body mass of the individuals, is investigated. MATERIAL AND METHODS The energy expenditure of a sample of 48 volunteers (21 females, 27 males) during a set of locomotion and burden transport trials was monitored. Two indexes were computed to compare the increment in the cost of locomotion relative to the load carried by sex. RESULTS The results demonstrate that both males and females, carrying the same relative loads, experience the same increment over the cost of their unloaded locomotion. Therefore, apart from obvious differences in body mass, there is no evidence of a dissimilar economy favoring one sex over the other that would explain the differences in load-carriage activities observed among current foraging populations. CONCLUSIONS These outcomes provide new conclusions about the constraints of the behavioral ecology of burden transport activities, and highlight the necessity to reevaluate, from an evolutionary perspective, the ideas about the sexual division of subsistence labor in hunter-gatherer and agriculturalist populations.
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Affiliation(s)
| | - Jesús Rodríguez
- National Research Center on Human Evolution (CENIEH), Burgos, Spain
| | | | | | - Ana Mateos
- National Research Center on Human Evolution (CENIEH), Burgos, Spain
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Benenson JF, Abadzi H. Contest versus scramble competition: sex differences in the quest for status. Curr Opin Psychol 2019; 33:62-68. [PMID: 31400660 DOI: 10.1016/j.copsyc.2019.07.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/22/2019] [Accepted: 07/07/2019] [Indexed: 12/21/2022]
Abstract
Both sexes benefit from attaining higher status than same-sex peers, but each sex employs distinctive competitive tactics. Men engage in conspicuous public contests for status and directly interfere with others' success. Despite frequent and intense contests which occasionally turn lethal, men typically employ ritualized tactics and accept status differentials within a group. More recently, research has examined women's subtle, safe, and often solitary, competitive tactics. Women's main competitive tactics consist of maintaining a few long-term alliances and gaining advantages when competitors are not present. When competitors are present, women utilize leveling, social exclusion, and low-cost forms of contest competition to best other women.
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Affiliation(s)
- Joyce F Benenson
- Harvard University, Department of Human Evolutionary, Biology, United States.
| | - Helen Abadzi
- University of Texas at Arlington, Department of Psychology, United States
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Stibbard‐Hawkes DNE. Costly signaling and the handicap principle in hunter‐gatherer research: A critical review. Evol Anthropol 2019; 28:144-157. [DOI: 10.1002/evan.21767] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 11/06/2018] [Accepted: 01/09/2019] [Indexed: 11/11/2022]
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Abstract
One of the most persistent debates in anthropology and related disciplines has been over the relative weight of aggression and competition versus nonaggression and cooperation as drivers of human behavioral evolution. The literature on hunting and gathering societies—past and present—has played a prominent role in these debates. This review compares recent literature from both sides of the argument and evaluates how accurately various authors use or misuse the ethnographic and archaeological research on hunters and gatherers. Whereas some theories provide a very poor fit with the hunter-gatherer evidence, others build their arguments around a much fuller range of the available data. The latter make a convincing case for models of human evolution that place at their center cooperative breeding and child-rearing, as well as management of conflict, flexible land tenure, and balanced gender relations.
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Affiliation(s)
- Richard B. Lee
- Department of Anthropology, University of Toronto, Toronto, Ontario M5S 1A1, Canada
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