1
|
Chaudhary N, Salali GD, Swanepoel A. Sensitive responsiveness and multiple caregiving networks among Mbendjele BaYaka hunter-gatherers: Potential implications for psychological development and well-being. Dev Psychol 2024; 60:422-440. [PMID: 37956035 DOI: 10.1037/dev0001601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Attachment theory postulates that there is a particular style of caregiving that, because of its interaction with our evolved psychology, is most likely to result in healthy psychological development. Attachment research has been criticized because most studies have been conducted with Western populations. Critics argue this has (a) overemphasized the importance of sensitive responsive caregiving and (b) limited our understanding of multiple nonmaternal caregiving (allomothering). Here, we analyze the extent of sensitive responsiveness and structural properties of allomothering networks among Mbendjele hunter-gatherers who reside in the Republic of Congo. Humans lived as hunter-gatherers for the majority of our evolutionary history, thus studying contemporary hunter-gatherers can offer insight into the caregiving children may be psychologically adapted to. Based on 12-hr focal follows of 18 children (0-4 years old; 10 male), we constructed caregiving networks across the domains of responding to crying, physical contact, interactive care, and proximity. Crying was virtually always responded to rapidly via comforting and never via scolding. Children received physical contact and care for the majority of the day. Allomothering accounted for 40%-50% of caregiving in each domain. While allomaternal networks were large, they were highly concentrated-the majority of a child's allocare was provided by just a few caregivers. Due to high caregiver:child ratios, "sharing" of caregivers was limited-a child typically had several allomothers who directed a majority of their allomaternal effort to him/her. These findings add to our understanding of the level and sources of sensitive responsive caregiving that children may be evolutionarily primed to expect. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
Collapse
Affiliation(s)
- Nikhil Chaudhary
- Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge
| | | | | |
Collapse
|
2
|
Page AE, Ringen EJ, Koster J, Borgerhoff Mulder M, Kramer K, Shenk MK, Stieglitz J, Starkweather K, Ziker JP, Boyette AH, Colleran H, Moya C, Du J, Mattison SM, Greaves R, Sum CY, Liu R, Lew-Levy S, Kiabiya Ntamboudila F, Prall S, Towner MC, Blumenfield T, Migliano AB, Major-Smith D, Dyble M, Salali GD, Chaudhary N, Derkx IE, Ross CT, Scelza BA, Gurven MD, Winterhalder BP, Cortez C, Pacheco-Cobos L, Schacht R, Macfarlan SJ, Leonetti D, French JC, Alam N, Zohora FT, Kaplan HS, Hooper PL, Sear R. Women's subsistence strategies predict fertility across cultures, but context matters. Proc Natl Acad Sci U S A 2024; 121:e2318181121. [PMID: 38346210 PMCID: PMC10907265 DOI: 10.1073/pnas.2318181121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/27/2023] [Indexed: 02/15/2024] Open
Abstract
While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities-incorporating market integration-are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as "farmers" did not have higher fertility than others, while "foragers" did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence.
Collapse
Affiliation(s)
- Abigail E. Page
- Division of Psychology, Brunel University of London, LondonUB8 3PN, United Kingdom
- Department of Population Health, London School of Hygiene and Tropical Medicine, LondonWC1E 7HT, United Kingdom
| | - Erik J. Ringen
- University of Zürich, Zürich8050, Switzerland
- Department of Comparative Language Science, University of Zürich, Zürich8050, Switzerland
- Center for the Interdisciplinary Study of Language Evolution, University of Zürich, Zürich8050, Switzerland
| | - Jeremy Koster
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Monique Borgerhoff Mulder
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
- Department of Anthropology, University of California, Davis, CA95616
| | - Karen Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT84112
| | - Mary K. Shenk
- Department of Anthropology, Penn State College of the Liberal Arts, State College, PA16801
| | - Jonathan Stieglitz
- Institute for Advanced Study in Toulouse, Universite Toulouse 1 Capitole, Toulouse31080, France
| | | | - John P. Ziker
- Department of Anthropology, Boise State University, Boise, ID83725
| | - Adam H. Boyette
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Heidi Colleran
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Cristina Moya
- Department of Anthropology, University of California, Davis, CA95616
| | - Juan Du
- State Key Laboratory of Grassland Agro-Ecosystem, College of Ecology, Lanzhou University, Lanzhou730000, China
| | - Siobhán M. Mattison
- Department of Anthropology, The University of New Mexico, Albuquerque, NM87106
| | - Russell Greaves
- Maxwell Museum of Anthropology, University of New Mexico, Albuquerque, NM87106
| | - Chun-Yi Sum
- Anthropology Department, Boston University, Boston, MA02215
| | - Ruizhe Liu
- Department of Anthropology, The University of New Mexico, Albuquerque, NM87106
| | - Sheina Lew-Levy
- Department of Psychology, Durham University, DurhamDH1 3LE, United Kingdom
| | - Francy Kiabiya Ntamboudila
- Faculté des Lettres, Arts, et Sciences Humaines, Département d’anthropologie, Marien Ngouabi University, Brazzaville, Congo
| | - Sean Prall
- Department of Anthropology, University of Missouri, Columbia, MO65201
| | - Mary C. Towner
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK74078
| | - Tami Blumenfield
- Department of Anthropology, The University of New Mexico, Albuquerque, NM87106
| | | | - Daniel Major-Smith
- Population Health Sciences, Bristol Medical School, University of Bristol, BristolBS8 2PS, United Kingdom
| | - Mark Dyble
- Department of Archaeology, University of Cambridge, CambridgeCB2 3DZ, United Kingdom
| | - Gul Deniz Salali
- Department of Anthropology, University College London, LondonWC1H 0BW, United Kingdom
| | - Nikhil Chaudhary
- Department of Archaeology, University of Cambridge, CambridgeCB2 3DZ, United Kingdom
| | - Inez E. Derkx
- Department of Anthropology, Universität Zürich, Zürich8050, Switzerland
| | - Cody T. Ross
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig04103, Germany
| | - Brooke A. Scelza
- Department of Anthropology, University of California, Los Angeles, CA90095
| | - Michael D. Gurven
- Department of Anthropology, University of California, Santa Barbara, CA93106
| | | | | | - Luis Pacheco-Cobos
- Facultad de Biología–Xalapa, Universidad Veracruzana, Zalapa-Enriquez91090, México
| | - Ryan Schacht
- Department of Anthropology, East Carolina University, Greenville, NC27858
| | | | - Donna Leonetti
- Department of Anthropology, University of Washington, Settle, WA98105
| | - Jennifer C. French
- Department of Archaeology, Classics and Egyptology, University of Liverpool, LiverpoolL69 7WZ, United Kingdom
| | - Nurul Alam
- Health Systems and Population Studies Division, International Centre for Diarrheal Disease Research, Bangladesh, Dhaka1213, Bangladesh
| | - Fatema tuz Zohora
- Health Systems and Population Studies Division, International Centre for Diarrheal Disease Research, Bangladesh, Dhaka1213, Bangladesh
| | - Hillard S. Kaplan
- Department of Anthropology, The University of New Mexico, Albuquerque, NM87106
| | - Paul L. Hooper
- Department of Anthropology, The University of New Mexico, Albuquerque, NM87106
| | - Rebecca Sear
- Department of Population Health, London School of Hygiene and Tropical Medicine, LondonWC1E 7HT, United Kingdom
| |
Collapse
|
3
|
Chaudhary N, Page AE, Salali GD, Dyble M, Major-Smith D, Migliano AB, Vinicius L, Thompson J, Viguier S. Hunter-Gatherer children's close-proximity networks: Similarities and differences with cooperative and communal breeding systems. Evol Hum Sci 2024; 6:e11. [PMID: 38516373 PMCID: PMC10955362 DOI: 10.1017/ehs.2024.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 03/23/2024] Open
Abstract
Among vertebrates, allomothering (non-maternal care) is classified as cooperative breeding (help from sexually mature non-breeders, usually close relatives) or communal breeding (shared care between multiple breeders who are not necessarily related). Humans have been described with both labels, most frequently as cooperative breeders. However, few studies have quantified the relative contributions of allomothers according to whether they are (a) sexually mature and reproductively active and (b) related or unrelated. We constructed close-proximity networks of Agta and BaYaka hunter-gatherers. We used portable remote-sensing devices to quantify the proportion of time children under the age of 4 spent in close proximity to different categories of potential allomother. Both related and unrelated, and reproductively active and inactive, campmates had substantial involvement in children's close-proximity networks. Unrelated campmates, siblings and subadults were the most involved in both populations, whereas the involvement of fathers and grandmothers was the most variable between the two populations. Finally, the involvement of sexually mature, reproductively inactive adults was low. Where possible, we compared our findings with studies of other hunter-gatherer societies, and observed numerous consistent trends. Based on our results we discuss why hunter-gatherer allomothering cannot be fully characterised as cooperative or communal breeding.
Collapse
Affiliation(s)
- Nikhil Chaudhary
- Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge, CambridgeCB2 1QH, UK
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Abigail E. Page
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Department of Population Health, London School of Hygiene and Tropical and Medicine, LondonWC1E 7HT, UK
| | - Gul Deniz Salali
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Mark Dyble
- Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge, CambridgeCB2 1QH, UK
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Daniel Major-Smith
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, BristolBS8 2BN, UK
| | - Andrea B. Migliano
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Department of Anthropology, University of Zurich, 8057Zürich, Switzerland
| | - Lucio Vinicius
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Department of Anthropology, University of Zurich, 8057Zürich, Switzerland
| | - James Thompson
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Sylvain Viguier
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| |
Collapse
|
4
|
Kretschmer L, Salali GD, Andersen LB, Hallal PC, Northstone K, Sardinha LB, Dyble M, Bann D. Gender differences in the distribution of children's physical activity: evidence from nine countries. Int J Behav Nutr Phys Act 2023; 20:103. [PMID: 37667391 PMCID: PMC10478357 DOI: 10.1186/s12966-023-01496-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 07/26/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Physical activity in childhood is thought to influences health and development. Previous studies have found that boys are typically more active than girls, yet the focus has largely been on differences in average levels or proportions above a threshold rather than the full distribution of activity across all intensities. We thus examined differences in the distribution of physical activity between girls and boys in a multi-national sample of children. METHODS We used the harmonised International Children Accelerometry Database (ICAD), including waist-worn accelerometry data from 15,461 individuals (Boys: 48.3%) from 9 countries. Employing Generalised Additive Models of Location, Shape, and Scale (GAMLSS) we investigated gender differences in the distribution of individuals, including comparisons of variability (SD) and average physical activity levels (mean and median) and skewness. We conducted this analysis for each activity intensity (Sedentary, Light, and Moderate-to-Vigorous (MVPA)) and a summary measure (counts per minute (CPM)). RESULTS Sizable gender differences in the distribution of activity were found for moderate to vigorous activity and counts per minute, with boys having higher average levels (38% higher mean volumes of MVPA, 20% higher CPM), yet substantially more between-person variability (30% higher standard deviation (SD) for MVPA, 17% higher SD for CPM); boys' distributions were less positively skewed than girls. Conversely, there was little to no difference between girls and boys in the distribution of sedentary or light-intensity activity. CONCLUSIONS Inequality in activity between girls and boys was driven by MVPA. The higher mean volumes of MVPA in boys occurred alongside greater variability. This suggests a need to consider the underlying distribution of activity in future research; for example, interventions which target gender inequality in MVPA may inadvertently lead to increased inequality within girls.
Collapse
Affiliation(s)
- Luke Kretschmer
- Centre for Longitudinal Studies, Social Research Institute, UCL, London, UK.
- Department of Anthropology, University College London, 14 Taviton Street, London, UK.
| | - Gul Deniz Salali
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Lars Bo Andersen
- Department of Sport, Food and Natural Sciences, Faculty of Teacher Education and Sports, Western Norway University of Applied Sciences, Sogndal, Norway
| | - Pedro C Hallal
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana-Champaign, USA
| | - Kate Northstone
- Bristol School of Medicine, Population Health Sciences, University of Bristol, Bristol, UK
| | - Luís B Sardinha
- Exercise and Health Laboratory, Faculdade de Motricidade Humana, CIPER, Universidade de Lisboa, Cruz Quebrada, Portugal
| | - Mark Dyble
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - David Bann
- Centre for Longitudinal Studies, Social Research Institute, UCL, London, UK
| |
Collapse
|
5
|
Abstract
In this study, we examined the relative effectiveness of prestige-based incentives (vaccination of an expert scientist/president/politician/celebrity/religious leader), conformist incentives (vaccination of friends and family) and risk-based incentives (witnessing death or illness of a person from the disease) for increasing participants' chances of getting vaccinated with respect to their coronavirus disease 2019 (COVID-19) vaccine intention. We conducted a cross-cultural survey using demographically representative samples from the UK (n = 1533), USA (n = 1550) and Turkey (n = 1567). The most effective incentives in all three countries were vaccination of an expert scientist, followed by vaccination of friends and family members and knowing someone dying from the disease. Vaccination of an expert scientist was significantly more effective at increasing vaccine intention than any other incentive. Vaccine incentives, regardless of the incentive type, were much less effective for those who originally refused the COVID-19 vaccine than for those who were hesitant to receive the vaccine. Although the percentage of vaccine-hesitant participants was highest in Turkey, the mean effectiveness scores of incentives were also the highest in Turkey, suggesting that an informed vaccine promotion strategy can be successful in this country. Our findings have policy applicability and suggest that positive vaccination messages delivered by expert scientists, vaccination of friends and family and risk-based incentives can be effective at increasing vaccine uptake.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Mete Sefa Uysal
- Department of Psychology, Dokuz Eylul University, Izmir, Turkey
| |
Collapse
|
6
|
Musciotto F, Dobon B, Greenacre M, Mira A, Chaudhary N, Salali GD, Gerbault P, Schlaepfer R, Astete LH, Ngales M, Gomez-Gardenes J, Latora V, Battiston F, Bertranpetit J, Vinicius L, Migliano AB. Agta hunter-gatherer oral microbiomes are shaped by contact network structure. Evol Hum Sci 2023; 5:e9. [PMID: 37587930 PMCID: PMC10426009 DOI: 10.1017/ehs.2023.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 12/24/2022] [Accepted: 01/08/2023] [Indexed: 02/25/2023] Open
Abstract
Here we investigate the effects of extensive sociality and mobility on the oral microbiome of 138 Agta hunter-gatherers from the Philippines. Our comparisons of microbiome composition showed that the Agta are more similar to Central African BaYaka hunter-gatherers than to neighbouring farmers. We also defined the Agta social microbiome as a set of 137 oral bacteria (only 7% of 1980 amplicon sequence variants) significantly influenced by social contact (quantified through wireless sensors of short-range interactions). We show that large interaction networks including strong links between close kin, spouses and even unrelated friends can significantly predict bacterial transmission networks across Agta camps. Finally, we show that more central individuals to social networks are also bacterial supersharers. We conclude that hunter-gatherer social microbiomes are predominantly pathogenic and were shaped by evolutionary tradeoffs between extensive sociality and disease spread.
Collapse
Affiliation(s)
- Federico Musciotto
- Dipartimento di Fisica e Chimica, Università di Palermo, Palermo, Italy
- Department of Anthropology, University of Zurich, Zurich, Switzerland
| | - Begoña Dobon
- Department of Anthropology, University of Zurich, Zurich, Switzerland
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Michael Greenacre
- Department of Economics and Business, Universitat Pompeu Fabra & Barcelona Graduate School of Economics, Barcelona, Spain
- Faculty of Biosciences, Fisheries and Economics, University of Tromsø, Norway
| | - Alex Mira
- Department of Health and Genomics, Center for Advanced Research in Public Health, FISABIO Foundation, Valencia, Spain
- CIBER Center for Epidemiology and Public Health, Madrid, Spain
| | - Nikhil Chaudhary
- Department of Archaeology, University of Cambridge, Cambridge, UK
| | - Gul Deniz Salali
- Department of Anthropology, University College London, London, UK
| | - Pascale Gerbault
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | | | - Leonora H. Astete
- Lyceum of the Philippines University, Intramuros, Manila, Philippines
| | - Marilyn Ngales
- Lyceum of the Philippines University, Intramuros, Manila, Philippines
| | - Jesus Gomez-Gardenes
- GOTHAM Lab, Institute for Biocomputation and Physics of Complex Systems, and Department of Condensed Matter Physics, University of Zaragoza, Zaragoza, Spain
- Center for Computational Social Science, Kobe University, Kobe, Japan
| | - Vito Latora
- School of Mathematical Sciences, Queen Mary University of London, London, UK
- Dipartimento di Fisica ed Astronomia, Università di Catania and INFN, Catania, Italy
- Complexity Science Hub Vienna, Vienna, Austria
| | - Federico Battiston
- Department of Anthropology, University of Zurich, Zurich, Switzerland
- Department of Network and Data Science, Central European University, Vienna, Austria
| | - Jaume Bertranpetit
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain
| | - Lucio Vinicius
- Department of Anthropology, University of Zurich, Zurich, Switzerland
- Department of Anthropology, University College London, London, UK
| | - Andrea Bamberg Migliano
- Department of Anthropology, University of Zurich, Zurich, Switzerland
- Department of Anthropology, University College London, London, UK
| |
Collapse
|
7
|
Major-Smith D, Chaudhary N, Dyble M, Major-Smith K, Page AE, Salali GD, Mace R, Migliano AB. Cooperation and partner choice among Agta hunter-gatherer children: An evolutionary developmental perspective. PLoS One 2023; 18:e0284360. [PMID: 37099506 PMCID: PMC10132543 DOI: 10.1371/journal.pone.0284360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 03/29/2023] [Indexed: 04/27/2023] Open
Abstract
Examining development is essential for a full understanding of behaviour, including how individuals acquire traits and how adaptive evolutionary forces shape these processes. The present study explores the development of cooperative behaviour among the Agta, a Filipino hunter-gatherer population. A simple resource allocation game assessing both levels of cooperation (how much children shared) and patterns of partner choice (who they shared with) was played with 179 children between the ages of 3 and 18. Children were given five resources (candies) and for each was asked whether to keep it for themselves or share with someone else, and if so, who this was. Between-camp variation in children's cooperative behaviour was substantial, and the only strong predictor of children's cooperation was the average level of cooperation among adults in camp; that is, children were more cooperative in camps where adults were more cooperative. Neither age, sex, relatedness or parental levels of cooperation were strongly associated with the amount children shared. Children preferentially shared with close kin (especially siblings), although older children increasingly shared with less-related individuals. Findings are discussed in terms of their implications for understanding cross-cultural patterns of children's cooperation, and broader links with human cooperative childcare and life history evolution.
Collapse
Affiliation(s)
- Daniel Major-Smith
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Department of Anthropology, University College London, London, United Kingdom
| | - Nikhil Chaudhary
- Department of Archaeology, Leverhulme Centre for Human Evolutionary Studies, University of Cambridge, Cambridge, United Kingdom
| | - Mark Dyble
- Department of Anthropology, University College London, London, United Kingdom
| | - Katie Major-Smith
- Department of Business and Social Sciences, Plymouth Marjon University, Plymouth, United Kingdom
| | - Abigail E Page
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gul Deniz Salali
- Department of Anthropology, University College London, London, United Kingdom
| | - Ruth Mace
- Department of Anthropology, University College London, London, United Kingdom
| | - Andrea B Migliano
- Department of Anthropology, University of Zurich, Zurich, Switzerland
| |
Collapse
|
8
|
Ene I, Wong KKY, Salali GD. Is it good to be bad? An evolutionary analysis of the adaptive potential of psychopathic traits. Evol Hum Sci 2022; 4:e37. [PMID: 37588932 PMCID: PMC10426111 DOI: 10.1017/ehs.2022.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Although psychopathy is widely conceptualised as a mental disorder, some researchers question the maladaptive nature of psychopathy, and argue that it might be advantageous from an evolutionary point of view. According to this view, psychopathy can be seen as an evolutionary adaptative strategy that relies on deception and manipulation to gain short-term reproductive benefits. Psychopathy is also identified as a fast life strategy in response to early life stress and an adaptation to harsh environments. This paper investigates the evidence that psychopathic traits are adaptive, while also addressing the limitations of current evolutionary models of psychopathy based on frequency-dependent selection and life history theory. We review recent studies on the fitness correlates of psychopathy and find that psychopathic traits present potential adaptive trade-offs between fertility and mortality, and offspring quantity and quality. On a proximate level, individual differences in stress reactivity and environmental risk factors in early development predispose to psychopathy through gene-environment interactions. We propose that environmental, developmental, social and cultural factors can mediate the relationship between psychopathic traits and fitness and therefore should be considered to make accurate predictions on the adaptive potential of psychopathy. We end by outlining gaps in the literature and making recommendations for future evolutionary research on psychopathy.
Collapse
Affiliation(s)
- Ioana Ene
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Keri Ka-Yee Wong
- Department of Psychology and Human Development, University College London, 25 Woburn Square, London WC1H 0AA, UK
| | - Gul Deniz Salali
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| |
Collapse
|
9
|
Salali GD, Uysal MS, Bozyel G, Akpinar E, Aksu A. Does social influence affect COVID-19 vaccination intention among the unvaccinated? Evol Hum Sci 2022; 4:e32. [PMID: 37588925 PMCID: PMC10426110 DOI: 10.1017/ehs.2022.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Conformist social influence is a double-edged sword when it comes to vaccine promotion. On the one hand, social influence may increase vaccine uptake by reassuring the hesitant about the safety and effectiveness of the vaccine; on the other hand, people may forgo the cost of vaccination when the majority is already vaccinated - giving rise to a public goods dilemma. Here, we examine whether available information on the percentage of double-vaccinated people affects COVID-19 vaccination intention among unvaccinated people in Turkey. In an online experiment, we divided participants (n = 1013) into low, intermediate and high social influence conditions, reflecting the government's vaccine promotion messages. We found that social influence did not predict COVID-19 vaccination intention, but psychological reactance and collectivism did. People with higher reactance (intolerance of others telling one what to do and being sceptical of consensus views) had lower vaccination intention, whilst people with higher collectivism (how much a person considers group benefits over individual success) had higher vaccination intention. Our findings suggest that advertising the percentage of double-vaccinated people is not sufficient to trigger a cascade of others getting themselves vaccinated. Diverse promotion strategies reflecting the heterogeneity of individual attitudes could be more effective.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College london, 14 Taviton Street, WC1H 0BW, UK
| | - Mete Sefa Uysal
- Department of Social Psychology, Friedrich Schiller University Jena, Jena, Germany
| | - Gizem Bozyel
- Department of Psychology, Dokuz Eylul University, Izmir, Turkey
| | - Ege Akpinar
- Deparment of Political Science and International Relations, Altinbas University, Istanbul, Turkey
| | - Ayca Aksu
- Department of Psychology, MEF University, Istanbul, Turkey
| |
Collapse
|
10
|
Abstract
BACKGROUND AND OBJECTIVES Most studies to date have focused on the negative aspects of anxiety. Anxiety, however, is an evolved emotional response that can provide protection in the face of risk. Pandemics are characterized by increased mortality risk coupled with future uncertainties, which both cause heightened anxiety. Here, we examine the factors associated with anxiety levels and risk avoidance behaviours during the first wave of the COVID-19 pandemic. We asked how individual time perspectives (future-oriented consideration and attention to present moment experience) affect anxiety in uncertain times, and whether anxiety reduces mortality risk by promoting risk avoidance behaviour. METHODOLOGY We conducted an online survey in the UK (N = 1088) and Turkey (N = 3935) and measured participants' generalized and pandemic-related anxiety levels, future-oriented consideration, mindfulness, intolerance of uncertainty, risk perception and risk avoidance behaviours. RESULTS We found that people less tolerant of uncertainties had higher levels of pandemic anxiety. Those with higher pandemic anxiety exhibited risk avoidance behaviours more frequently. Mindfulness and increased financial satisfaction reduced pandemic anxiety. People in Turkey reported higher levels of generalized and pandemic anxiety and greater engagement in risk avoidance behaviours than people in the UK. CONCLUSIONS AND IMPLICATIONS Our study shows an elevated anxiety response can help mitigate infection risk during pandemics and emphasizes the importance of the underlying situation in understanding whether an anxiety response is adaptive or pathological. Maintaining a healthy level of anxiety can promote engagement in protective behaviours. Therapies addressing anxiety can focus on increasing tolerance to future uncertainties. LAY SUMMARY Anxiety is an emotional response triggered in the anticipation of a possible threat. We found that intolerance of uncertainty strongly predicted anxiety and that people with elevated anxiety levels engaged in protective behaviours more frequently during the COVID-19 pandemic, suggesting that anxiety can help mitigate mortality risk.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Mete Sefa Uysal
- Psychology Department, Dokuz Eylül University, Izmir, Turkey.,Department of Social Psychology, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Abi Bevan
- Department of Anthropology, University College London, London WC1H 0BW, UK
| |
Collapse
|
11
|
Knight JK, Salali GD, Sikka G, Derkx I, Keestra SM, Chaudhary N. Quantifying patterns of alcohol consumption and its effects on health and wellbeing among BaYaka hunter-gatherers: A mixed-methods cross-sectional study. PLoS One 2021; 16:e0258384. [PMID: 34705859 PMCID: PMC8550590 DOI: 10.1371/journal.pone.0258384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/24/2021] [Indexed: 12/13/2022] Open
Abstract
Ethnographers frequently allude to alcoholism and related harms in Indigenous hunter-gatherer communities, but very few studies have quantified patterns of alcohol consumption or its health and social impacts. We present a case study of the Mbendjele BaYaka, a Congolese population undergoing socioeconomic transition. 83 adults answered questions about their frequency and quantity of alcohol consumption, underwent biometric measurements and reported whether they were currently experiencing a cough or diarrhoea; 56 participated in structured interviews about their experiences with alcohol. Based on WHO standards, we found 44.3% of the full sample, and 51.5% of drinkers (excluding abstainers), had a hazardous volume of alcohol consumption; and 35.1% of the full sample, and 40.9% of drinkers, engaged in heavy episodic drinking; consumption habits varied with sex and age. Total weekly consumption was a positive predictor of blood pressure and the likelihood of experiencing diarrhoea; associations with other biometric variables were not statistically significant. Interview responses indicated numerous other economic, mental and physical health harms of alcohol use, the prevalence of which demonstrate some variability between forest camps and permanent village settlements. These include high rates of drinking during pregnancy and breastfeeding (~40%); frequent alcohol-induced violence; and considerable exchange of foraged foods and engagement in exploitative labour activities to acquire alcohol or repay associated debts. Our findings demonstrate the prevalence of hazardous alcohol consumption among transitioning hunter-gatherers is higher than other segments of the Congolese population and indicate negative impacts on health and wellbeing, highlighting an urgent need for targeted public health interventions.
Collapse
Affiliation(s)
- Jessica K. Knight
- Department of Archaeology, Leverhulme Centre for Human Evolutionary Studies, University of Cambridge, Cambridge, United Kingdom
- University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Gul Deniz Salali
- Department of Anthropology, University College London, London, United Kingdom
| | - Gaurav Sikka
- Department of Anthropology, University College London, London, United Kingdom
| | - Inez Derkx
- Department of Anthropology, University College London, London, United Kingdom
- Department of Anthropology, University of Zurich, Zürich, Switzerland
| | - Sarai M. Keestra
- Department of Anthropology, University College London, London, United Kingdom
- Department of Anthropology, Durham University, Durham, United Kingdom
| | - Nikhil Chaudhary
- Department of Archaeology, Leverhulme Centre for Human Evolutionary Studies, University of Cambridge, Cambridge, United Kingdom
- Department of Anthropology, University College London, London, United Kingdom
| |
Collapse
|
12
|
Keestra SM, Male V, Salali GD. Out of balance: the role of evolutionary mismatches in the sex disparity in autoimmune disease. Med Hypotheses 2021; 151:110558. [PMID: 33964604 DOI: 10.1016/j.mehy.2021.110558] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/07/2021] [Accepted: 03/02/2021] [Indexed: 12/28/2022]
Abstract
Over the past century autoimmune disease incidence has increased rapidly in (post-) industrialised, affluent societies, suggesting that changes in ecology and lifestyle are driving this development. Epidemiological studies show that (i) 80% of autoimmune disease patients are female, (ii) autoimmune diseases co-occur more often in women, and (iii) the incidence of some autoimmune diseases is increasing faster in women than in men. The female preponderance in autoimmunity is most pronounced between puberty and menopause, suggesting that diverging sex hormone levels during the reproductive years are implicated in autoimmune disease development. Using an evolutionary perspective, we build on the hypotheses that female immunity is cyclical in menstruating species and that natural selection shaped the female immune system to optimise the implantation and gestation of a semi-allogeneic foetus. We propose that cyclical immunomodulation and female immune tolerance mechanisms are currently out of balance because of a mismatch between the conditions under which they evolved and (post-)industrialised, affluent lifestyles. We suggest that current changes in autoimmune disease prevalence may be caused by increases in lifetime exposure to cyclical immunomodulation and ovarian hormone exposure, reduced immune challenges, increased reproductive lifespan, changed reproductive patterns, and enhanced positive energy balance associated with (post-)industrialised, affluent lifestyles. We discuss proximate mechanisms by which oestrogen and progesterone influence tolerance induction and immunomodulation, and review the effect of the menstrual cycle, pregnancy, and contraceptive use on autoimmune disease incidence and symptoms.
Collapse
Affiliation(s)
- Sarai M Keestra
- Amsterdam UMC, University of Amsterdam, the Netherlands; Department of Global Health & Development, London School of Hygiene and Tropical Medicine, UK.
| | - Victoria Male
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, UK
| | | |
Collapse
|
13
|
Arnot M, Brandl E, Campbell OLK, Chen Y, Du J, Dyble M, Emmott EH, Ge E, Kretschmer LDW, Mace R, Micheletti AJC, Nila S, Peacey S, Salali GD, Zhang H. How evolutionary behavioural sciences can help us understand behaviour in a pandemic. Evol Med Public Health 2020; 2020:264-278. [PMID: 33318799 PMCID: PMC7665496 DOI: 10.1093/emph/eoaa038] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022] Open
Abstract
The COVID-19 pandemic has brought science into the public eye and to the attention of governments more than ever before. Much of this attention is on work in epidemiology, virology and public health, with most behavioural advice in public health focusing squarely on 'proximate' determinants of behaviour. While epidemiological models are powerful tools to predict the spread of disease when human behaviour is stable, most do not incorporate behavioural change. The evolutionary basis of our preferences and the cultural evolutionary dynamics of our beliefs drive behavioural change, so understanding these evolutionary processes can help inform individual and government decision-making in the face of a pandemic. Lay summary: The COVID-19 pandemic has brought behavioural sciences into the public eye: Without vaccinations, stopping the spread of the virus must rely on behaviour change by limiting contact between people. On the face of it, "stop seeing people" sounds simple. In practice, this is hard. Here we outline how an evolutionary perspective on behaviour change can provide additional insights. Evolutionary theory postulates that our psychology and behaviour did not evolve to maximize our health or that of others. Instead, individuals are expected to act to maximise their inclusive fitness (i.e, spreading our genes) - which can lead to a conflict between behaviours that are in the best interests for the individual, and behaviours that stop the spread of the virus. By examining the ultimate explanations of behaviour related to pandemic-management (such as behavioural compliance and social distancing), we conclude that "good of the group" arguments and "one size fits all" policies are unlikely to encourage behaviour change over the long-term. Sustained behaviour change to keep pandemics at bay is much more likely to emerge from environmental change, so governments and policy makers may need to facilitate significant social change - such as improving life experiences for disadvantaged groups.
Collapse
Affiliation(s)
- Megan Arnot
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Eva Brandl
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - O L K Campbell
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Yuan Chen
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou University, 222 Tianshui South Rd, Lanzhou, Gansu Province 730000, People's Republic of China
| | - Juan Du
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou University, 222 Tianshui South Rd, Lanzhou, Gansu Province 730000, People's Republic of China
| | - Mark Dyble
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Emily H Emmott
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Erhao Ge
- State Key Laboratory of Grassland and Agro-ecosystems, School of Life Sciences, Lanzhou University, 222 Tianshui South Rd, Lanzhou, Gansu Province 730000, People's Republic of China
| | - Luke D W Kretschmer
- Department of Epidemiology and Public Health, University College London, 1-19 Torrington Place, London, UK
| | - Ruth Mace
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Alberto J C Micheletti
- Institute for Advanced Study in Toulouse, Université Toulouse 1 Capitole, 1 esplanade de l’Université, 31080 Toulouse Cedex 06, France
| | - Sarah Nila
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Sarah Peacey
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Gul Deniz Salali
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| | - Hanzhi Zhang
- Department of Anthropology, University College London, 14 Taviton Street, London, UK
| |
Collapse
|
14
|
Salali GD, Uysal MS. COVID-19 vaccine hesitancy is associated with beliefs on the origin of the novel coronavirus in the UK and Turkey. Psychol Med 2020; 52:1-3. [PMID: 33070804 PMCID: PMC7609204 DOI: 10.1017/s0033291720004067] [Citation(s) in RCA: 188] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/05/2020] [Accepted: 10/13/2020] [Indexed: 12/02/2022]
Abstract
BACKGROUND Much research effort is focused on developing an effective vaccine for combatting coronavirus disease 2019 (COVID-19). Vaccine development itself, however, will not be enough given that a sufficient amount of people will need to be vaccinated for widespread immunity. Vaccine hesitancy is on the rise, varies across countries, and is associated with conspiratorial worldview. Given the rise in COVID-19-related conspiracy theories, we aimed to examine the levels of COVID-19 vaccine hesitancy and its association with beliefs on the origin of the novel coronavirus in a cross-cultural study. METHODS We conducted an online survey in the UK (N = 1088) and Turkey (N = 3936), and gathered information on participants' willingness to vaccinate for a potential COVID-19 vaccine, beliefs on the origin of the novel coronavirus, and several behavioural and demographic predictors (such as anxiety, risk perception, government satisfaction levels) that influence vaccination and origin beliefs. RESULTS In all, 31% of the participants in Turkey and 14% in the UK were unsure about getting themselves vaccinated for a COVID-19 vaccine. In both countries, 3% of the participants rejected to be vaccinated. Also, 54% of the participants in Turkey and 63% in the UK believed in the natural origin of the novel coronavirus. Believing in the natural origin significantly increased the odds of COVID-19 vaccine acceptance. CONCLUSIONS Our results point at a concerning level of COVID-19 vaccine hesitancy, especially in Turkey, and suggest that wider communication of the scientific consensus on the origin of the novel coronavirus with the public may help future campaigns targeting COVID-19 vaccine hesitancy.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Mete Sefa Uysal
- Department of Psychology, Dokuz Eylul University, Izmir, Turkey
| |
Collapse
|
15
|
Salali GD, Dyble M, Chaudhary N, Sikka G, Derkx I, Keestra SM, Smith D, Thompson J, Vinicius L, Migliano AB. Global WEIRDing: transitions in wild plant knowledge and treatment preferences in Congo hunter-gatherers. Evol Hum Sci 2020; 2:e24. [PMID: 37588372 PMCID: PMC10427474 DOI: 10.1017/ehs.2020.26] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cultures around the world are converging as populations become more connected. On the one hand this increased connectedness can promote the recombination of existing cultural practices to generate new ones, but on the other it may lead to the replacement of traditional practices and global WEIRDing. Here we examine the process and causes of changes in cultural traits concerning wild plant knowledge in Mbendjele BaYaka hunter-gatherers from Congo. Our results show that the BaYaka who were born in town reported knowing and using fewer plants than the BaYaka who were born in forest camps. Plant uses lost in the town-born BaYaka related to medicine. Unlike the forest-born participants, the town-born BaYaka preferred Western medicine over traditional practices, suggesting that the observed decline of plant knowledge and use is the result of replacement of cultural practices with the new products of cumulative culture.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Mark Dyble
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Nikhil Chaudhary
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge, Cambridge, CB2 1QH, UK
| | - Gaurav Sikka
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Inez Derkx
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Department of Anthropology, University of Zurich, 8057Zürich, Switzerland
| | - Sarai M. Keestra
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Department of Anthropology, Durham University, DurhamDH1 3LE, UK
| | - Daniel Smith
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Bristol Medical School: Population Health Sciences, University of Bristol, BristolBS8 2BN, UK
| | - James Thompson
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
| | - Lucio Vinicius
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Department of Anthropology, University of Zurich, 8057Zürich, Switzerland
| | - Andrea Bamberg Migliano
- Department of Anthropology, University College London, LondonWC1H 0BW, UK
- Department of Anthropology, University of Zurich, 8057Zürich, Switzerland
| |
Collapse
|
16
|
Page AE, Thomas MG, Smith D, Dyble M, Viguier S, Chaudhary N, Salali GD, Thompson J, Mace R, Migliano AB. Testing adaptive hypotheses of alloparenting in Agta foragers. Nat Hum Behav 2019; 3:1154-1163. [PMID: 31406338 PMCID: PMC6858278 DOI: 10.1038/s41562-019-0679-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 07/05/2019] [Indexed: 11/29/2022]
Abstract
Human children are frequently cared for by non-parental caregivers (alloparents), yet few studies have conducted systematic alternative hypothesis tests of why alloparents help. Here we explore whether predictions from kin selection, reciprocity, learning-to-mother and costly signalling hypotheses explain non-parental childcare among Agta hunter-gatherers from the Philippines. To test these hypotheses, we used high-resolution proximity data from 1,701 child-alloparent dyads. Our results indicated that reciprocity and relatedness were positively associated with the number of interactions with a child (our proxy for childcare). Need appeared more influential in close kin, suggesting indirect benefits, while reciprocity proved to be a stronger influence in non-kin, pointing to direct benefits. However, despite shared genes, close and distant kin interactions were also contingent on reciprocity. Compared with other apes, humans are unique in rapidly producing energetically demanding offspring. Our results suggest that the support that mothers require is met through support based on kinship and reciprocity.
Collapse
Affiliation(s)
- Abigail E Page
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, UK.
- Department of Anthropology, University College London, London, UK.
| | - Matthew G Thomas
- Department of Anthropology, University College London, London, UK
| | - Daniel Smith
- Bristol Medical School, University of Bristol, Bristol, UK
| | - Mark Dyble
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Sylvain Viguier
- Department of Anthropology, University College London, London, UK
| | - Nikhil Chaudhary
- Department of Archaeology, University of Cambridge, Cambridge, UK
| | - Gul Deniz Salali
- Department of Anthropology, University College London, London, UK
| | - James Thompson
- Department of Anthropology, University College London, London, UK
| | - Ruth Mace
- Department of Anthropology, University College London, London, UK
| | - Andrea B Migliano
- Department of Anthropology, University of Zurich, Zurich, Switzerland
| |
Collapse
|
17
|
Salali GD, Chaudhary N, Bouer J, Thompson J, Vinicius L, Migliano AB. Development of social learning and play in BaYaka hunter-gatherers of Congo. Sci Rep 2019; 9:11080. [PMID: 31367002 PMCID: PMC6668464 DOI: 10.1038/s41598-019-47515-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/10/2019] [Indexed: 11/16/2022] Open
Abstract
High-fidelity transmission of information through imitation and teaching has been proposed as necessary for cumulative cultural evolution. Yet, it is unclear when and for which knowledge domains children employ different social learning processes. This paper explores the development of social learning processes and play in BaYaka hunter-gatherer children by analysing video recordings and time budgets of children from early infancy to adolescence. From infancy to early childhood, hunter-gatherer children learn mainly by imitating and observing others’ activities. From early childhood, learning occurs mainly in playgroups and through practice. Throughout childhood boys engage in play more often than girls whereas girls start foraging wild plants from early childhood and spend more time in domestic activities and childcare. Sex differences in play reflect the emergence of sexual division of labour and the play-work transition occurring earlier for girls. Consistent with theoretical models, teaching occurs for skills/knowledge that cannot be transmitted with high fidelity through other social learning processes such as the acquisition of abstract information e.g. social norms. Whereas, observational and imitative learning occur for the transmission of visually transparent skills such as tool use, foraging, and cooking. These results suggest that coevolutionary relationships between human sociality, language and teaching have likely been fundamental in the emergence of human cumulative culture.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College London, London, WC1H 0BW, United Kingdom.
| | - Nikhil Chaudhary
- Department of Anthropology, University College London, London, WC1H 0BW, United Kingdom.,Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge, Cambridge, CB2 1QH, United Kingdom
| | - Jairo Bouer
- Department of Anthropology, University College London, London, WC1H 0BW, United Kingdom
| | - James Thompson
- Department of Anthropology, University College London, London, WC1H 0BW, United Kingdom
| | - Lucio Vinicius
- Department of Anthropology, University College London, London, WC1H 0BW, United Kingdom.,Department of Anthropology, University of Zurich, 8057, Zürich, Switzerland
| | - Andrea Bamberg Migliano
- Department of Anthropology, University College London, London, WC1H 0BW, United Kingdom.,Department of Anthropology, University of Zurich, 8057, Zürich, Switzerland
| |
Collapse
|
18
|
Smith D, Dyble M, Major K, Page AE, Chaudhary N, Salali GD, Thompson J, Vinicius L, Migliano AB, Mace R. A friend in need is a friend indeed: Need-based sharing, rather than cooperative assortment, predicts experimental resource transfers among Agta hunter-gatherers. EVOL HUM BEHAV 2019. [DOI: 10.1016/j.evolhumbehav.2018.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
19
|
Smith D, Schlaepfer P, Major K, Dyble M, Page AE, Thompson J, Chaudhary N, Salali GD, Mace R, Astete L, Ngales M, Vinicius L, Migliano AB. Cooperation and the evolution of hunter-gatherer storytelling. Nat Commun 2017; 8:1853. [PMID: 29208949 PMCID: PMC5717173 DOI: 10.1038/s41467-017-02036-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/02/2017] [Indexed: 12/05/2022] Open
Abstract
Storytelling is a human universal. From gathering around the camp-fire telling tales of ancestors to watching the latest television box-set, humans are inveterate producers and consumers of stories. Despite its ubiquity, little attention has been given to understanding the function and evolution of storytelling. Here we explore the impact of storytelling on hunter-gatherer cooperative behaviour and the individual-level fitness benefits to being a skilled storyteller. Stories told by the Agta, a Filipino hunter-gatherer population, convey messages relevant to coordinating behaviour in a foraging ecology, such as cooperation, sex equality and egalitarianism. These themes are present in narratives from other foraging societies. We also show that the presence of good storytellers is associated with increased cooperation. In return, skilled storytellers are preferred social partners and have greater reproductive success, providing a pathway by which group-beneficial behaviours, such as storytelling, can evolve via individual-level selection. We conclude that one of the adaptive functions of storytelling among hunter gatherers may be to organise cooperation. Storytelling entails costs in terms of time and effort, yet it is a ubiquitous feature of human society. Here, Smith et al. show benefits of storytelling in Agta hunter-gatherer communities, as storytellers have higher reproductive success and storytelling is associated with higher cooperation in the group.
Collapse
Affiliation(s)
- Daniel Smith
- Department of Anthropology, University College London, London, WC1H 0BW, UK. .,Bristol Medical School: Population Health Sciences, University of Bristol, Bristol, BS8 2BN, UK.
| | | | - Katie Major
- Bristol Zoological Society, Bristol, BS8 3HA, UK
| | - Mark Dyble
- Jesus College, University of Cambridge, Jesus Lane, Cambridge, CB5 8BL, UK.,Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Abigail E Page
- Department of Anthropology, University College London, London, WC1H 0BW, UK
| | - James Thompson
- Department of Anthropology, University College London, London, WC1H 0BW, UK
| | - Nikhil Chaudhary
- Department of Anthropology, University College London, London, WC1H 0BW, UK
| | - Gul Deniz Salali
- Department of Anthropology, University College London, London, WC1H 0BW, UK
| | - Ruth Mace
- Department of Anthropology, University College London, London, WC1H 0BW, UK.,School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Leonora Astete
- Lyceum of the Philippines University, Community Outreach and Service Learning, Manila, 1002, Philippines
| | - Marilyn Ngales
- Lyceum of the Philippines University, Community Outreach and Service Learning, Manila, 1002, Philippines
| | - Lucio Vinicius
- Department of Anthropology, University College London, London, WC1H 0BW, UK
| | | |
Collapse
|
20
|
Mesman J, Minter T, Angnged A, Cissé IAH, Salali GD, Migliano AB. Universality Without Uniformity: A Culturally Inclusive Approach to Sensitive Responsiveness in Infant Caregiving. Child Dev 2017; 89:837-850. [DOI: 10.1111/cdev.12795] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
21
|
Salali GD, Chaudhary N, Thompson J, Grace OM, van der Burgt XM, Dyble M, Page AE, Smith D, Lewis J, Mace R, Vinicius L, Migliano AB. Knowledge-Sharing Networks in Hunter-Gatherers and the Evolution of Cumulative Culture. Curr Biol 2016; 26:2516-2521. [PMID: 27618264 DOI: 10.1016/j.cub.2016.07.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/29/2016] [Accepted: 07/08/2016] [Indexed: 12/01/2022]
Abstract
Humans possess the unique ability for cumulative culture [1, 2]. It has been argued that hunter-gatherer's complex social structure [3-9] has facilitated the evolution of cumulative culture by allowing information exchange among large pools of individuals [10-13]. However, empirical evidence for the interaction between social structure and cultural transmission is scant [14]. Here we examine the reported co-occurrence of plant uses between individuals in dyads (which we define as their "shared knowledge" of plant uses) in BaYaka Pygmies from Congo. We studied reported uses of 33 plants of 219 individuals from four camps. We show that (1) plant uses by BaYaka fall into three main domains: medicinal, foraging, and social norms/beliefs; (2) most medicinal plants have known bioactive properties, and some are positively associated with children's BMI, suggesting that their use is adaptive; (3) knowledge of medicinal plants is mainly shared between spouses and biological and affinal kin; and (4) knowledge of plant uses associated with foraging and social norms is shared more widely among campmates, regardless of relatedness, and is important for camp-wide activities that require cooperation. Our results show the interdependence between social structure and knowledge sharing. We propose that long-term pair bonds, affinal kin recognition, exogamy, and multi-locality create ties between unrelated families, facilitating the transmission of medicinal knowledge and its fitness implications. Additionally, multi-family camps with low inter-relatedness between camp members provide a framework for the exchange of functional information related to cooperative activities beyond the family unit, such as foraging and regulation of social life.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College London, London WC1H 0BW, UK.
| | - Nikhil Chaudhary
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - James Thompson
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | | | | | - Mark Dyble
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Abigail E Page
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Daniel Smith
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Jerome Lewis
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Ruth Mace
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | - Lucio Vinicius
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | | |
Collapse
|
22
|
Dyble M, Thompson J, Smith D, Salali GD, Chaudhary N, Page AE, Vinicuis L, Mace R, Migliano AB. Networks of Food Sharing Reveal the Functional Significance of Multilevel Sociality in Two Hunter-Gatherer Groups. Curr Biol 2016; 26:2017-2021. [PMID: 27451900 DOI: 10.1016/j.cub.2016.05.064] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 04/28/2016] [Accepted: 05/26/2016] [Indexed: 11/29/2022]
Abstract
Like many other mammalian and primate societies [1-4], humans are said to live in multilevel social groups, with individuals situated in a series of hierarchically structured sub-groups [5, 6]. Although this multilevel social organization has been described among contemporary hunter-gatherers [5], questions remain as to the benefits that individuals derive from living in such groups. Here, we show that food sharing among two populations of contemporary hunter-gatherers-the Palanan Agta (Philippines) and Mbendjele BaYaka (Republic of Congo)-reveals similar multilevel social structures, with individuals situated in households, within sharing clusters of 3-4 households, within the wider residential camps, which vary in size. We suggest that these groupings serve to facilitate inter-sexual provisioning, kin provisioning, and risk reduction reciprocity, three levels of cooperation argued to be fundamental in human societies [7, 8]. Humans have a suite of derived life history characteristics including a long childhood and short inter-birth intervals that make offspring energetically demanding [9] and have moved to a dietary niche that often involves the exploitation of difficult to acquire foods with highly variable return rates [10-12]. This means that human foragers face both day-to-day and more long-term energetic deficits that conspire to make humans energetically interdependent. We suggest that a multilevel social organization allows individuals access to both the food sharing partners required to buffer themselves against energetic shortfalls and the cooperative partners required for skill-based tasks such as cooperative foraging.
Collapse
Affiliation(s)
- Mark Dyble
- Anthropology, University College London, London WC1E 6BT, UK.
| | - James Thompson
- Anthropology, University College London, London WC1E 6BT, UK
| | - Daniel Smith
- Anthropology, University College London, London WC1E 6BT, UK
| | | | | | - Abigail E Page
- Anthropology, University College London, London WC1E 6BT, UK
| | - Lucio Vinicuis
- Anthropology, University College London, London WC1E 6BT, UK
| | - Ruth Mace
- Anthropology, University College London, London WC1E 6BT, UK
| | | |
Collapse
|
23
|
Smith D, Dyble M, Thompson J, Major K, Page AE, Chaudhary N, Salali GD, Vinicius L, Migliano AB, Mace R. Camp stability predicts patterns of hunter-gatherer cooperation. R Soc Open Sci 2016; 3:160131. [PMID: 27493770 PMCID: PMC4968462 DOI: 10.1098/rsos.160131] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/17/2016] [Indexed: 05/02/2023]
Abstract
Humans regularly cooperate with non-kin, which has been theorized to require reciprocity between repeatedly interacting and trusting individuals. However, the role of repeated interactions has not previously been demonstrated in explaining real-world patterns of hunter-gatherer cooperation. Here we explore cooperation among the Agta, a population of Filipino hunter-gatherers, using data from both actual resource transfers and two experimental games across multiple camps. Patterns of cooperation vary greatly between camps and depend on socio-ecological context. Stable camps (with fewer changes in membership over time) were associated with greater reciprocal sharing, indicating that an increased likelihood of future interactions facilitates reciprocity. This is the first study reporting an association between reciprocal cooperation and hunter-gatherer band stability. Under conditions of low camp stability individuals still acquire resources from others, but do so via demand sharing (taking from others), rather than based on reciprocal considerations. Hunter-gatherer cooperation may either be characterized as reciprocity or demand sharing depending on socio-ecological conditions.
Collapse
Affiliation(s)
- Daniel Smith
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Mark Dyble
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - James Thompson
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Katie Major
- Bristol Zoological Society, Clifton, Bristol BS8 3HA, UK
| | - Abigail E. Page
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Nikhil Chaudhary
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Gul Deniz Salali
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Lucio Vinicius
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Andrea Bamberg Migliano
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| | - Ruth Mace
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK
| |
Collapse
|
24
|
Page AE, Viguier S, Dyble M, Smith D, Chaudhary N, Salali GD, Thompson J, Vinicius L, Mace R, Migliano AB. Reproductive trade-offs in extant hunter-gatherers suggest adaptive mechanism for the Neolithic expansion. Proc Natl Acad Sci U S A 2016; 113:4694-9. [PMID: 27071109 PMCID: PMC4855554 DOI: 10.1073/pnas.1524031113] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The Neolithic demographic transition remains a paradox, because it is associated with both higher rates of population growth and increased morbidity and mortality rates. Here we reconcile the conflicting evidence by proposing that the spread of agriculture involved a life history quality-quantity trade-off whereby mothers traded offspring survival for increased fertility, achieving greater reproductive success despite deteriorating health. We test this hypothesis by investigating fertility, mortality, health, and overall reproductive success in Agta hunter-gatherers whose camps exhibit variable levels of sedentarization, mobility, and involvement in agricultural activities. We conducted blood composition tests in 345 Agta and found that viral and helminthic infections as well as child mortality rates were significantly increased with sedentarization. Nonetheless, both age-controlled fertility and overall reproductive success were positively affected by sedentarization and participation in cultivation. Thus, we provide the first empirical evidence, to our knowledge, of an adaptive mechanism in foragers that reconciles the decline in health and child survival with the observed demographic expansion during the Neolithic.
Collapse
Affiliation(s)
- Abigail E Page
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - Sylvain Viguier
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - Mark Dyble
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - Daniel Smith
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - Nikhil Chaudhary
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - Gul Deniz Salali
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - James Thompson
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - Lucio Vinicius
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | - Ruth Mace
- Department of Anthropology, University College London, London WC1H 0BW, United Kingdom
| | | |
Collapse
|
25
|
Salali GD, Whitehouse H, Hochberg ME. A Life-Cycle Model of Human Social Groups Produces a U-Shaped Distribution in Group Size. PLoS One 2015; 10:e0138496. [PMID: 26381745 PMCID: PMC4575040 DOI: 10.1371/journal.pone.0138496] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 08/30/2015] [Indexed: 12/03/2022] Open
Abstract
One of the central puzzles in the study of sociocultural evolution is how and why transitions from small-scale human groups to large-scale, hierarchically more complex ones occurred. Here we develop a spatially explicit agent-based model as a first step towards understanding the ecological dynamics of small and large-scale human groups. By analogy with the interactions between single-celled and multicellular organisms, we build a theory of group lifecycles as an emergent property of single cell demographic and expansion behaviours. We find that once the transition from small-scale to large-scale groups occurs, a few large-scale groups continue expanding while small-scale groups gradually become scarcer, and large-scale groups become larger in size and fewer in number over time. Demographic and expansion behaviours of groups are largely influenced by the distribution and availability of resources. Our results conform to a pattern of human political change in which religions and nation states come to be represented by a few large units and many smaller ones. Future enhancements of the model should include decision-making rules and probabilities of fragmentation for large-scale societies. We suggest that the synthesis of population ecology and social evolution will generate increasingly plausible models of human group dynamics.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Institut des Sciences de l'Evolution, Université de Montpellier, Place E Bataillon, 34095, Montpellier, Cedex 5, France
- Department of Anthropology, University College London, 14 Taviton Street, London, WC1H 0BW, United Kingdom
| | - Harvey Whitehouse
- Institute of Cognitive and Evolutionary Anthropology, University of Oxford, Oxford, OX2 6PN, United Kingdom
| | - Michael E. Hochberg
- Institut des Sciences de l'Evolution, Université de Montpellier, Place E Bataillon, 34095, Montpellier, Cedex 5, France
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, New Mexico, 87501, United States of America
- * E-mail:
| |
Collapse
|
26
|
Salali GD, Migliano AB. Future Discounting in Congo Basin Hunter-Gatherers Declines with Socio-Economic Transitions. PLoS One 2015; 10:e0137806. [PMID: 26381883 PMCID: PMC4575175 DOI: 10.1371/journal.pone.0137806] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 08/21/2015] [Indexed: 11/18/2022] Open
Abstract
Humans have a tendency to discount the future; that is we value small, short-term rewards over larger, long-term rewards. The degree of future discounting, however, changes in response to socio-ecological factors. Here, we study Mbendjele BaYaka hunter-gatherers of northern Congo and their farmer neighbours to investigate adaptations in inter-temporal preferences in humans. We argue that in immediate-return systems, where food storage is absent and egalitarianism is enforced through levelling mechanisms, future discounting is an adaptive strategy to prevent wealth accumulation and the emergence of hierarchies. This ensures food sharing and allows for survival in unpredictable environments where there is risk of an energy shortfall. On the other hand, when food storage is made possible by the emergence of agriculture or as seen in some delayed-return hunter-gatherer populations, wealth accumulation, hierarchies and lower discount rates become the adaptive strategy. Therefore, individuals in immediate-return, egalitarian societies will discount the future more than those in non-egalitarian, delayed-return societies. Consistent with the predictions we found that market integration and socio-economic transitions decrease the future discounting in Mbendjele hunter-gatherers. Our measures of socio-economic differences marked this transition in hunter-gatherers living in a logging town. The degree of future-discounting was the same between more market-integrated hunter-gatherers and their farmer neighbours.
Collapse
Affiliation(s)
- Gul Deniz Salali
- Department of Anthropology, University College London, London, United Kingdom
| | | |
Collapse
|
27
|
Dyble M, Salali GD, Chaudhary N, Page A, Smith D, Thompson J, Vinicius L, Mace R, Migliano AB. Human behavior. Sex equality can explain the unique social structure of hunter-gatherer bands. Science 2015; 348:796-8. [PMID: 25977551 DOI: 10.1126/science.aaa5139] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The social organization of mobile hunter-gatherers has several derived features, including low within-camp relatedness and fluid meta-groups. Although these features have been proposed to have provided the selective context for the evolution of human hypercooperation and cumulative culture, how such a distinctive social system may have emerged remains unclear. We present an agent-based model suggesting that, even if all individuals in a community seek to live with as many kin as possible, within-camp relatedness is reduced if men and women have equal influence in selecting camp members. Our model closely approximates observed patterns of co-residence among Agta and Mbendjele BaYaka hunter-gatherers. Our results suggest that pair-bonding and increased sex egalitarianism in human evolutionary history may have had a transformative effect on human social organization.
Collapse
Affiliation(s)
- M Dyble
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK.
| | - G D Salali
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| | - N Chaudhary
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| | - A Page
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| | - D Smith
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| | - J Thompson
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| | - L Vinicius
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| | - R Mace
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| | - A B Migliano
- University College London (UCL) Anthropology, 14 Taviton Street, London WC1H 0BW, UK
| |
Collapse
|
28
|
Chaudhary N, Salali GD, Thompson J, Dyble M, Page A, Smith D, Mace R, Migliano AB. Polygyny without wealth: popularity in gift games predicts polygyny in BaYaka Pygmies. R Soc Open Sci 2015; 2:150054. [PMID: 26064662 PMCID: PMC4453254 DOI: 10.1098/rsos.150054] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/07/2015] [Indexed: 05/17/2023]
Abstract
The occurrence of polygynous marriage in hunter-gatherer societies, which do not accumulate wealth, remains largely unexplored since resource availability is dependent on male hunting capacity and limited by the lack of storage. Hunter-gatherer societies offer the greatest insight in to human evolution since they represent the majority of our species' evolutionary history. In order to elucidate the evolution of hunter-gatherer polygyny, we study marriage patterns of BaYaka Pygmies. We investigate (i) rates of polygyny among BaYaka hunter-gatherers; (ii) whether polygyny confers a fitness benefit to BaYaka men; (iii) in the absence of wealth inequalities, what are the alternative explanations for polygyny among the BaYaka. To understand the latter, we explore differences in phenotypic quality (height and strength), and social capital (popularity in gift games). We find polygynous men have increased reproductive fitness; and that social capital and popularity but not phenotypic quality might have been important mechanisms by which some male hunter-gatherers sustained polygynous marriages before the onset of agriculture and wealth accumulation.
Collapse
Affiliation(s)
- Nikhil Chaudhary
- Department of Anthropology, University College London, London WC1H 0BW, UK
| | | | | | | | | | | | | | | |
Collapse
|
29
|
|
30
|
Tanner CJ, Salali GD, Jackson AL. The ghost of social environments past: dominance relationships include current interactions and experience carried over from previous groups. Biol Lett 2011; 7:818-21. [PMID: 21561961 DOI: 10.1098/rsbl.2011.0325] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dominance hierarchies pervade animal societies. Within a static social environment, in which group size and composition are unchanged, an individual's hierarchy rank results from intrinsic (e.g. body size) and extrinsic (e.g. previous experiences) factors. Little is known, however, about how dominance relationships are formed and maintained when group size and composition are dynamic. Using a fusion-fission protocol, we fused groups of previously isolated shore crabs (Carcinus maenas) into larger groups, and then restored groups to their original size and composition. Pre-fusion hierarchies formed independently of individuals' sizes, and were maintained within a static group via winner/loser effects. Post-fusion hierarchies differed from pre-fusion ones; losing fights during fusion led to a decline in an individual's rank between pre- and post-fusion conditions, while spending time being aggressive during fusion led to an improvement in rank. In post-fusion tanks, larger individuals achieved better ranks than smaller individuals. In conclusion, dominance hierarchies in crabs represent a complex combination of intrinsic and extrinsic factors, in which experiences from previous groups can carry over to affect current competitive interactions.
Collapse
Affiliation(s)
- Colby J Tanner
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Republic of Ireland.
| | | | | |
Collapse
|