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Wiley KS, Gregg AM, Fox MM, Lagishetty V, Sandman CA, Jacobs JP, Glynn LM. Contact with caregivers is associated with composition of the infant gastrointestinal microbiome in the first 6 months of life. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:e24858. [PMID: 37804008 PMCID: PMC10922139 DOI: 10.1002/ajpa.24858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/18/2023] [Accepted: 09/24/2023] [Indexed: 10/08/2023]
Abstract
OBJECTIVES Little is known about how physical contact at birth and early caregiving environments influence the colonization of the infant gastrointestinal microbiome. We investigated how infant contact with caregivers at birth and within the first 2 weeks of life relates to the composition of the gastrointestinal microbiome in a sample of U.S. infants (n = 60). METHODS Skin-to-skin and physical contact with caregivers at birth and early caregiving environments were surveyed at 2 weeks postpartum. Stool samples were collected from infants at 2 weeks, 2, 6, and 12 months of age and underwent 16S rRNA sequencing as a proxy for the gastrointestinal microbiome. Associations between early caregiving environments and alpha and beta diversity, and differential abundance of bacteria at the genus level were assessed using PERMANOVA, and negative binomial mixed models in DEseq2. RESULTS Time in physical contact with caregivers explained 10% of variation in beta diversity at 2 weeks' age. The number of caregivers in the first few weeks of life explained 9% of variation in beta diversity at 2 weeks and the number of individuals in physical contact at birth explained 11% of variation in beta diversity at 6 months. Skin-to-skin contact on the day of birth was positively associated with the abundance of eight genera. Infants held for by more individuals had greater abundance of eight genera. DISCUSSION Results reveal a potential mechanism (skin-to-skin and physical contact) by which caregivers influence the infant gastrointestinal microbiome. Our findings contribute to work exploring the social transmission of microbes.
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Affiliation(s)
- Kyle S Wiley
- Department of Anthropology, UCLA, Los Angeles, California, USA
- Department of Psychiatry & Biobehavioral Sciences, UCLA, Los Angeles, California, USA
| | - Andrew M Gregg
- The Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Molly M Fox
- Department of Anthropology, UCLA, Los Angeles, California, USA
- Department of Psychiatry & Biobehavioral Sciences, UCLA, Los Angeles, California, USA
| | - Venu Lagishetty
- The Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- UCLA Microbiome Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Division of Gastroenterology, Hepatology and Parenteral Nutrition, VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Curt A Sandman
- Department of Psychiatry and Human Behavior, UC Irvine, Irvine, California, USA
| | - Jonathan P Jacobs
- The Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- UCLA Microbiome Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Division of Gastroenterology, Hepatology and Parenteral Nutrition, VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Laura M Glynn
- Department of Psychology, Chapman University, Orange, California, USA
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Kudrnova V, Spelke ES, Thomas AJ. Infants Infer Social Relationships Between Individuals Who Engage in Imitative Social Interactions. Open Mind (Camb) 2024; 8:202-216. [PMID: 38476663 PMCID: PMC10932586 DOI: 10.1162/opmi_a_00124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 12/17/2023] [Indexed: 03/14/2024] Open
Abstract
Infants are born into rich social networks and are faced with the challenge of learning about them. When infants observe social interactions, they make predictions about future behavior, but it is not clear whether these predictions are based on social dispositions, social relationships, or both. The current studies (N = 188, N = 90 males) address this question in 12-month-old infants and 16- to 18-month-old toddlers who observe social interactions involving imitation. In Studies 1 and 3, infants and toddlers expected that imitators, compared to non-imitators, would respond to their social partners' distress. Likewise, they expected the targets of imitation, compared to non-targets, to respond to their partner's distress. In Study 2, these expectations did not generalize to interactions with a new partner, providing evidence that infants learned about the relationships between individuals as opposed to their dispositions. In Study 3, infants did not make predictions about responses to laughter, suggesting that infants see imitation as indicative of a specific kind of social relationship. Together, these results provide evidence that imitative interactions support infants' and toddlers' learning about the social relationships connecting unknown individuals.
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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. EVOLUTIONARY HUMAN SCIENCES 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] [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.
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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
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Caffé B, Blackwell A, Fehrenkamp BD, Williams JE, Pace RM, Lackey KA, Ruiz L, Rodríguez JM, McGuire MA, Foster JA, Sellen DW, Kamau-Mbuthia EW, Kamundia EW, Mbugua S, Moore SE, Prentice AM, Kvist LJ, Otoo GE, Pareja RG, Bode L, Gebeyehu D, Gindola DK, Boothman S, Flores K, McGuire MK, Meehan CL. Human milk immune factors, maternal nutritional status, and infant sex: The INSPIRE study. Am J Hum Biol 2023; 35:e23943. [PMID: 37358306 PMCID: PMC10749986 DOI: 10.1002/ajhb.23943] [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: 01/14/2023] [Revised: 05/24/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023] Open
Abstract
OBJECTIVES Breastfeeding is an energetically costly and intense form of human parental investment, providing sole-source nutrition in early infancy and bioactive components, including immune factors. Given the energetic cost of lactation, milk factors may be subject to tradeoffs, and variation in concentrations have been explored utilizing the Trivers-Willard hypothesis. As human milk immune factors are critical to developing immune system and protect infants against pathogens, we tested whether concentrations of milk immune factors (IgA, IgM, IgG, EGF, TGFβ2, and IL-10) vary in response to infant sex and maternal condition (proxied by maternal diet diversity [DD] and body mass index [BMI]) as posited in the Trivers-Willard hypothesis and consider the application of the hypothesis to milk composition. METHODS We analyzed concentrations of immune factors in 358 milk samples collected from women residing in 10 international sites using linear mixed-effects models to test for an interaction between maternal condition, including population as a random effect and infant age and maternal age as fixed effects. RESULTS IgG concentrations were significantly lower in milk produced by women consuming diets with low diversity with male infants than those with female infants. No other significant associations were identified. CONCLUSIONS IgG concentrations were related to infant sex and maternal diet diversity, providing minimal support for the hypothesis. Given the lack of associations across other select immune factors, results suggest that the Trivers-Willard hypothesis may not be broadly applied to human milk immune factors as a measure of maternal investment, which are likely buffered against perturbations in maternal condition.
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Affiliation(s)
- Beatrice Caffé
- Department of Anthropology, Washington State University, Pullman, Washington, USA
| | - Aaron Blackwell
- Department of Anthropology, Washington State University, Pullman, Washington, USA
| | - Bethaney D Fehrenkamp
- Margaret Ritchie School of Family and Consumer Sciences, University of Idaho, Moscow, Idaho, USA
- Washington, Wyoming, Alaska, Montana, Idaho (WWAMI) Medical Education Program, University of Idaho, Moscow, Idaho, USA
| | - Janet E Williams
- Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, Idaho, USA
| | - Ryan M Pace
- Margaret Ritchie School of Family and Consumer Sciences, University of Idaho, Moscow, Idaho, USA
| | - Kimberly A Lackey
- Margaret Ritchie School of Family and Consumer Sciences, University of Idaho, Moscow, Idaho, USA
| | - Lorena Ruiz
- Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Villaviciosa, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Microhealth Group, Oviedo, Spain
| | - Juan M Rodríguez
- Department of Nutrition and Food Science, Complutense University of Madrid, Madrid, Spain
| | - Mark A McGuire
- Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, Idaho, USA
| | - James A Foster
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, USA
| | - Daniel W Sellen
- Department of Anthropology, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Samwel Mbugua
- Department of Human Nutrition, Egerton University, Nakuru, Kenya
| | - Sophie E Moore
- Department of Women and Children's Health, King's College London, London, UK
- MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, Gambia
| | - Andrew M Prentice
- MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, Gambia
| | | | - Gloria E Otoo
- Department of Nutrition and Food Science, University of Ghana, Accra, Ghana
| | | | - Lars Bode
- Larsson-Rosenquist Foundation Mother-Milk-Infant Center of Research Excellence, University of California, San Diego, La Jolla, California, USA
- Department of Pediatrics, University of California, San Diego, La Jolla, California, USA
| | - Dubale Gebeyehu
- Department of Anthropology, Hawassa University, Hawassa, Ethiopia
| | - Debela K Gindola
- Department of Anthropology, Hawassa University, Hawassa, Ethiopia
| | - Sarah Boothman
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Katherine Flores
- Department of Anthropology, Washington State University, Pullman, Washington, USA
| | - Michelle K McGuire
- Margaret Ritchie School of Family and Consumer Sciences, University of Idaho, Moscow, Idaho, USA
| | - Courtney L Meehan
- Department of Anthropology, Washington State University, Pullman, Washington, USA
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Holdsworth EA, Williams JE, Pace RM, Lane AA, Gartstein M, McGuire MA, McGuire MK, Meehan CL. Breastfeeding patterns are associated with human milk microbiome composition: The Mother-Infant Microbiomes, Behavior, and Ecology Study (MIMBES). PLoS One 2023; 18:e0287839. [PMID: 37556398 PMCID: PMC10411759 DOI: 10.1371/journal.pone.0287839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 06/14/2023] [Indexed: 08/11/2023] Open
Abstract
The human milk microbiome (HMM) is hypothesized to be seeded by multiple factors, including the infant oral microbiome during breastfeeding. However, it is not known whether breastfeeding patterns (e.g., frequency or total time) impact the composition of the HMM. As part of the Mother-Infant Microbiomes, Behavior, and Ecology Study (MIMBES), we analyzed data from naturalistic observations of 46 mother-infant dyads living in the US Pacific Northwest and analyzed milk produced by the mothers for its bacterial diversity and composition. DNA was extracted from milk and the V1-V3 region of the 16S rRNA gene was amplified and sequenced. We hypothesized that number of breastfeeding bouts (breastfeeding sessions separated by >30 seconds) and total time breastfeeding would be associated with HMM α-diversity (richness, diversity, or evenness) and differential abundance of HMM bacterial genera. Multiple linear regression was used to examine associations between HMM α-diversity and the number of breastfeeding bouts or total time breastfeeding and selected covariates (infant age, maternal work outside the home, frequency of allomother physical contact with the infant, non-household caregiving network). HMM richness was inversely associated with number of breastfeeding bouts and frequency of allomother physical contact, but not total time breastfeeding. Infants' non-household caregiving network was positively associated with HMM evenness. In two ANCOM-BC analyses, abundances of 5 of the 35 most abundant genera were differentially associated with frequency of breastfeeding bouts (Bifidobacterium, Micrococcus, Pedobacter, Acidocella, Achromobacter); 5 genera (Bifidobacterium, Agreia, Pedobacter, Rugamonas, Stenotrophomonas) were associated with total time breastfeeding. These results indicate that breastfeeding patterns and infant caregiving ecology may play a role in influencing HMM composition. Future research is needed to identify whether these relationships are consistent in other populations and if they are associated with variation in the infant's gastrointestinal (including oral) microbiome.
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Affiliation(s)
- Elizabeth A. Holdsworth
- Department of Anthropology, Washington State University, Pullman, Washington, United States of America
| | - Janet E. Williams
- Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Ryan M. Pace
- Margaret Ritchie School of Family and Consumer Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Avery A. Lane
- Department of Anthropology, Washington State University, Pullman, Washington, United States of America
| | - Maria Gartstein
- Department of Psychology, Washington State University, Pullman, Washington, United States of America
| | - Mark A. McGuire
- Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Michelle K. McGuire
- Margaret Ritchie School of Family and Consumer Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Courtney L. Meehan
- Department of Anthropology, Washington State University, Pullman, Washington, United States of America
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Helfrecht C, Dira SJ. The Sidama Model of Human Development. HUMAN NATURE (HAWTHORNE, N.Y.) 2023:10.1007/s12110-023-09449-z. [PMID: 37101096 DOI: 10.1007/s12110-023-09449-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Accepted: 04/05/2023] [Indexed: 04/28/2023]
Abstract
Human ontogeny has been shaped through evolution, resulting in markers of physical, cognitive, and social development that are widely shared and often used to demarcate the lifespan. Yet, development is demonstrably biocultural and strongly influenced by context. As a result, emic age categories can vary in duration and composition, constituted by both common physical markers as well as culturally meaningful indicators, with implications for our understanding of the evolution of human life history. Semi-structured group interviews (n = 24) among Sidama adults and children, as well as individual interviews with children (n = 30), were used to identify age categories across the lifespan and to specifically investigate acquisition of sociocultural skills and cognitive development. Ten major age categories were identified, covering birth through death. These largely map onto patterning of human universals, but specific cultural beliefs and behaviors were indicated as important markers of development. Adults and children are oriented toward the dynamic relationships between physical development and acquisition of skills tied to social and cultural success. Culture, ecology, and ontogeny are co-determinants of human development, and the interactions among them should be considered in studies examining human life history and its evolution.
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Affiliation(s)
- Courtney Helfrecht
- Department of Anthropology, University of Alabama, Box 870210, Tuscaloosa, AL, USA.
| | - Samuel Jilo Dira
- Department of Anthropology, Hawassa University, Hawassa, Ethiopia
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Fox SA, Scelza B, Silk J, Kramer KL. New perspectives on the evolution of women's cooperation. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210424. [PMID: 36440567 PMCID: PMC9703265 DOI: 10.1098/rstb.2021.0424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 09/28/2022] [Indexed: 11/29/2022] Open
Abstract
A holistic, evolutionary framework about human cooperation must incorporate information about women's cooperative behaviour. Yet, most empirical research on human cooperation has centered on men's behaviour or been derived from experimental studies conducted in western, industrialized populations. These bodies of data are unlikely to accurately represent human behavioural diversity. To address this gap and provide a more balanced view of human cooperation, this issue presents substantial new data and multi-disciplinary perspectives to document the complexity of women's cooperative behaviour. Research in this issue 1) challenges narratives about universal gender differences in cooperation, 2) reconsiders patrilocality and access to kin as constraints on women's cooperation, 3) reviews evidence for a connection between social support and women's health and 4) examines the phylogenetic roots of female cooperation. Here, we discuss the steps taken in this issue toward a more complete and evidence-based understanding of the role that cooperation plays in women's and girls' lives and in building human sociality. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.
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Affiliation(s)
- Stephanie A. Fox
- Department of Anthropology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Brooke Scelza
- Department of Anthropology, UCLA, Los Angeles, CA 90095, USA
| | - Joan Silk
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85281, USA
| | - Karen L. Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA
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Kramer KL. Female cooperation: evolutionary, cross-cultural and ethnographic evidence. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210425. [PMID: 36440565 PMCID: PMC9703230 DOI: 10.1098/rstb.2021.0425] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 08/11/2022] [Indexed: 11/29/2022] Open
Abstract
Women and girls cooperate with each other across many domains and at many scales. However, much of this information is buried in the ethnographic record and has been overlooked in theoretic constructions of the evolution of human sociality and cooperation. The assumed primacy of male bonding, hunting, patrilocality and philopatry has dominated the discussion of cooperation without balanced consideration. A closer look at the ethnographic record reveals that in addition to cooperative childcare and food production, women and girls collectively form coalitions, have their own cooperative political, ceremonial, economic and social institutions, and develop female-based exchange and support networks. The numerous ethnographic examples of female cooperation urge reconsideration of gender stereotypes and the limits of female cooperation. This review brings together theoretic, cross-cultural and cross-lifespan research on female cooperation to present a more even and empirically supported view of female sociality. Following the lead from trends in evolutionary biology and sexual selection theory, the hope going forward is that the focus shifts from rote characterizations of sex differences to highlighting sources of variation and conditions that enhance or constrain female cooperative engagement. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.
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Affiliation(s)
- Karen L. Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA
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9
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Starkweather KE, Reynolds AZ, Zohora F, Alam N. Shodagor women cooperate across domains of work and childcare to solve an adaptive problem. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210433. [PMID: 36440563 PMCID: PMC9703234 DOI: 10.1098/rstb.2021.0433] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 05/03/2022] [Indexed: 11/29/2022] Open
Abstract
Across human societies, women's economic production and their contributions to childcare are critical in supporting reproductive fitness for themselves, their spouses and children. Yet, the necessity of performing both work and childcare tasks presents women with an adaptive problem in which they must determine how best to allocate their time and energy between these tasks. Women often use cooperative relationships with alloparents to solve this problem, but whether or not women cooperate across different domains (e.g. work and childcare) to access alloparents remains relatively under-explored. Using social network data collected with Shodagor households in Bangladesh, we show that women who need childcare help in order to work draw on cooperative work partners as potential alloparents, and that all women rely heavily on kin, but not reciprocal cooperation for childcare help. These results indicate that Shodagor women strategize to create work and childcare relationships in ways that help solve the adaptive problem they face. We discuss the implications of our results and the example provided by Shodagor women for a broader understanding of women's cooperative relationships, including the importance of socio-ecological circumstances and gendered divisions of labour in shaping women's cooperative strategies. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.
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Affiliation(s)
- K. E. Starkweather
- Department of Anthropology, University of Illinois Chicago, Chicago, IL 60607, USA
- Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - A. Z. Reynolds
- Department of Anthropology, University of New Mexico, Albuquerque, NM 8731, USA
| | - F. Zohora
- Health Systems and Population Studies Division, ICDDR,B, Dhaka 1212, Bangladesh
| | - N. Alam
- Health Systems and Population Studies Division, ICDDR,B, Dhaka 1212, Bangladesh
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Hackman J, Kramer KL. Kin networks and opportunities for reproductive cooperation and conflict among hunter-gatherers. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210434. [PMID: 36440562 PMCID: PMC9703223 DOI: 10.1098/rstb.2021.0434] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 10/03/2022] [Indexed: 11/29/2022] Open
Abstract
Little is known about the potential for reproductive conflict among hunter-gatherer populations, who are characterized by bilateral kinship ties, flexible residential mobility, and high offspring mortality. To assess the potential for reproductive conflict, we use longitudinal residence and reproductive history data for two bands of South American foragers. Using multilevel logistic regressions (N = 44 women, N = 712 person years), we examine how yearly measures of (i) camp composition, (ii) distribution of female kin and (iii) a woman's position in a female kinship network impact the likelihood of giving birth or experiencing a child's death. We compare conflict models to a demographic model that accounts for the proportion of women giving birth in a given year. Contrary to conflict models, results show that the odds of giving birth increase with the presence of highly related women. However, the odds of experiencing an offspring death are insensitive to the presence of coresident women. Network measures of closeness and centrality in the female kin network also show no significant effect on reproductive outcomes. Furthermore, chances of both births and deaths increase in years when proportionally more women are giving birth. We argue that demographic stochasticity relating to ecological conditions best predicts reproductive outcomes for women. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.
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Affiliation(s)
- Joseph Hackman
- Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA
| | - Karen L. Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA
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Simpson CR, Power EA. Dynamics of cooperative networks associated with gender among South Indian Tamils. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210437. [PMID: 36440558 PMCID: PMC9703249 DOI: 10.1098/rstb.2021.0437] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 07/16/2022] [Indexed: 11/29/2022] Open
Abstract
Helping behaviour is thought to play a major role in the evolution of group-living animals. Yet, it is unclear to what extent human males and human females use the same strategies to secure support. Accordingly, we investigate help-seeking over a 5-year period in relation to gender using data from virtually all adults in two Tamil villages (N = 782). Simulations of network dynamics (i.e. stochastic actor-oriented models) calibrated to these data broadly indicate that women are more inclined than men to create and maintain supportive bonds via multiple mechanisms of cooperation (e.g. reciprocity, kin bias, friend bias, generalized exchange). However, gender-related differences in the simulated dynamics of help-seeking are modest, vary based on structural position (e.g. out-degree), and do not appear to translate to divergence in the observed structure of respondents' egocentric networks. Findings ultimately suggest that men and women in the two villages are similarly social but channel their sociality differently. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.
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Affiliation(s)
- Cohen R. Simpson
- Nuffield College, University of Oxford, Oxford OX1 1NF, UK
- Department of Methodology, The London School of Economics and Political Science, London WC2A 2AE, UK
| | - Eleanor A. Power
- Department of Methodology, The London School of Economics and Political Science, London WC2A 2AE, UK
- The Santa Fe Institute, Santa Fe, NM 87501, USA
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Page AE, Migliano AB, Dyble M, Major-Smith D, Viguier S, Hassan A. Sedentarization and maternal childcare networks: role of risk, gender and demography. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210435. [PMID: 36440566 PMCID: PMC9703224 DOI: 10.1098/rstb.2021.0435] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 05/26/2022] [Indexed: 11/29/2022] Open
Abstract
Women cooperate over multiple domains and while research from western contexts portrays women's networks as limited in size and breadth, women receive help, particularly with childcare, from a diverse range of individuals (allomothers). Nonetheless, little exploration has occurred into why we see such diversity. Wide maternal childcare networks may be a consequence of a lack of resource accumulation in mobile hunter-gatherers-where instead households rely on risk-pooling in informal insurance networks. By contrast, when households settle and accumulate resources, they are able to retain risk by absorbing losses. Thus, the size and composition of mothers' childcare networks may depend on risk-buffering, as captured by mobile and settled households in the Agta, a Philippine foraging population with diverse lifestyles. Across 78 children, we find that childcare from grandmothers and sisters was higher in settled camps, while childcare from male kin was lower, offering little support for risk-buffering. Nonetheless, girls' workloads were increased in settled camps while grandmothers had fewer dependent children, increasing their availability. These results point to gender-specific changes associated with shifting demographics as camps become larger and more settled. Evidently, women's social networks, rather than being constrained by biology, are responsive to the changing socioecological context. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.
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Affiliation(s)
- Abigail E. Page
- Department of Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Andrea B. Migliano
- Department of Anthropology, University of Zürich, Zurich 8006, Switzerland
| | - Mark Dyble
- Department of Anthropology, University College London, London WC1E 6BT, UK
| | - Daniel Major-Smith
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol BS8 1TH, UK
| | - Sylvain Viguier
- Department of Anthropology, University College London, London WC1E 6BT, UK
- Graphcore, Lynton House, 7–12 Tavistock Square, London WC1H 9LT, UK
| | - Anushé Hassan
- Department of Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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Jang H, Janmaat KRL, Kandza V, Boyette AH. Girls in early childhood increase food returns of nursing women during subsistence activities of the BaYaka in the Republic of Congo. Proc Biol Sci 2022; 289:20221407. [PMID: 36382518 PMCID: PMC9667358 DOI: 10.1098/rspb.2022.1407] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Nursing mothers face an energetic trade-off between infant care and work. Under pooled energy budgets, this trade-off can be reduced by assistance in food acquisition and infant care tasks from non-maternal carers. Across cultures, children also often provide infant care. Yet the question of who helps nursing mothers during foraging has been understudied, especially the role of children. Using focal follow data from 140 subsistence expeditions by BaYaka women in the Republic of Congo, we investigated how potential support from carers increased mothers' foraging productivity. We found that the number of girls in early childhood (ages 4–7 years) in subsistence groups increased food returns of nursing women with infants (kcal collected per minute). This effect was stronger than that of other adult women, and older girls in middle childhood (ages 8–13 years) and adolescence (ages 14–19 years). Child helpers were not necessarily genetically related to nursing women. Our results suggest that it is young girls who provide infant care while nursing mothers are acquiring food—by holding, monitoring and playing with infants—and, thus, that they also contribute to the energy pool of the community during women's subsistence activities. Our study highlights the critical role of children as carers from early childhood.
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Affiliation(s)
- Haneul Jang
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Karline R. L. Janmaat
- Department of Evolutionary and Population Biology, Institute of Biodiversity and Ecosystem Dynamics, Faculty of Science, University of Amsterdam, 94248 Amsterdam, The Netherlands
- Department of Cognitive Psychology, Faculty of Social and Behavioral Sciences, Leiden University, 2333 Leiden, The Netherlands
| | - Vidrige Kandza
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Adam H. Boyette
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
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14
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Infants infer potential social partners by observing the interactions of their parent with unknown others. Proc Natl Acad Sci U S A 2022; 119:e2121390119. [PMID: 35878009 PMCID: PMC9371719 DOI: 10.1073/pnas.2121390119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Infants are born into networks of individuals who are socially connected. How do infants begin learning which individuals are their own potential social partners? Using digitally edited videos, we showed 12-mo-old infants' social interactions between unknown individuals and their own parents. In studies 1 to 4, after their parent showed affiliation toward one puppet, infants expected that puppet to engage with them. In study 5, infants made the reverse inference; after a puppet engaged with them, the infants expected that puppet to respond to their parent. In each study, infants' inferences were specific to social interactions that involved their own parent as opposed to another infant's parent. Thus, infants combine observation of social interactions with knowledge of their preexisting relationship with their parent to discover which newly encountered individuals are potential social partners for themselves and their families.
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15
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Ivey Henry P, Morelli GA. Niche Construction in Hunter-Gatherer Infancy: Growth and Health Trade-Offs Inform Social Agency. EVOLUTIONARY PSYCHOLOGY 2022. [DOI: 10.1007/978-3-030-76000-7_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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16
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Fox M, Wiley KS. How a pregnant woman's relationships with her siblings relate to her mental health: a prenatal allocare perspective. Evol Med Public Health 2021; 10:1-20. [PMID: 35154777 PMCID: PMC8830312 DOI: 10.1093/emph/eoab044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In cooperatively breeding species, individuals may promote their inclusive fitness through allomothering. Humans exhibit some features of cooperative breeding, and previous studies have focused on allomothering by grandparents and juvenile siblings in the postnatal period. We hypothesize that a pregnant woman's relationships with her siblings (offspring's maternal aunts and uncles) are beneficial for maternal affect in ways that can enhance the siblings' inclusive fitness. Maternal affect during pregnancy is a salient target of allocare given the detrimental effects of antepartum mood disorders on birth and infant outcomes. METHODOLOGY We test our hypotheses in a cohort of pregnant Latina women in Southern California (N = 201). Predictor variables of interest include number of siblings a participant has, if she has sisters, frequency of seeing siblings, and frequency of communication with siblings. Outcome variables measuring maternal affect include depression, state anxiety, pregnancy-related anxiety and perceived stress. RESULTS Having at least one sister and greater frequency of communication with siblings were associated with fewer depressive symptoms during pregnancy. No significant associations were found between sibling variables and other measures of affect. CONCLUSION AND IMPLICATIONS Results suggest that how frequently you communicate with, and not how often you see, siblings could be protective against risk of antepartum depression. Sibling allomothering could impart effects through social-emotional support rather than instrumental support, as a strategy to benefit the prenatal environment in which future nieces and nephews develop. Allomothering may be particularly important in cultural contexts that value family relationships. Future studies should investigate other communities.
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Affiliation(s)
- Molly Fox
- Department of Anthropology, University of California Los Angeles, Los Angeles, CA, USA,Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA,Corresponding author. Department of Anthropology, University of California Los Angeles, 341 Haines Hall, 375 Portola Plaza, Los Angeles, CA, USA. Tel: +1 (310) 206-4589; E-mail:
| | - Kyle S Wiley
- Department of Anthropology, University of California Los Angeles, Los Angeles, CA, USA,Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA
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17
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Rilling JK, Gonzalez A, Lee M. The neural correlates of grandmaternal caregiving. Proc Biol Sci 2021; 288:20211997. [PMID: 34784762 PMCID: PMC8596004 DOI: 10.1098/rspb.2021.1997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/21/2021] [Indexed: 01/04/2023] Open
Abstract
In many societies, grandmothers are important caregivers, and grandmaternal investment is often associated with improved grandchild well-being. Here, we present, to our knowledge, the first study to examine grandmaternal brain function. We recruited 50 grandmothers with at least one biological grandchild between 3 and 12 years old. Brain function was measured with functional magnetic resonance imaging as grandmothers viewed pictures of their grandchild, an unknown child, the same-sex parent of the grandchild, and an unknown adult. Grandmothers also completed questionnaires to measure their degree of involvement with and attachment to their grandchild. After controlling for age and familiarity of stimuli, viewing grandchild pictures activated areas involved with emotional empathy (insula and secondary somatosensory cortex) and movement (motor cortex and supplementary motor area). Grandmothers who more strongly activated areas involved with cognitive empathy (temporo-parietal junction and dorsomedial prefrontal cortex) when viewing pictures of the grandchild desired greater involvement in caring for the grandchild. Finally, compared with results from an earlier study of fathers, grandmothers more strongly activated regions involved with emotional empathy (dorsal anterior cingulate cortex, insula and secondary somatosensory cortex), and motivation (nucleus accumbens, ventral pallidum and caudate nucleus). All in all, our findings suggest that emotional empathy may be a key component of grandmaternal responses to their grandchildren.
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Affiliation(s)
- James K. Rilling
- Department of Anthropology, Emory University, Atlanta, GA, USA
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
- Center for Behavioral Neuroscience, Emory University, Atlanta, GA, USA
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Center for Translational Social Neuroscience, Emory University, Atlanta, GA, USA
| | - Amber Gonzalez
- Department of Anthropology, Emory University, Atlanta, GA, USA
| | - Minwoo Lee
- Department of Anthropology, Emory University, Atlanta, GA, USA
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18
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Starkweather KE, Keith MH, Prall SP, Alam N, Zohora F, Emery Thompson M. Are fathers a good substitute for mothers? Paternal care and growth rates in Shodagor children. Dev Psychobiol 2021; 63:e22148. [PMID: 34087947 DOI: 10.1002/dev.22148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 05/18/2021] [Accepted: 05/20/2021] [Indexed: 12/21/2022]
Abstract
Biparental care is a hallmark of human social organization, though paternal investment varies between and within societies. The facultative nature of paternal care in humans suggests males should invest when their care improves child survival and/or quality, though testing this prediction can be challenging because of the difficulties of empirically isolating paternal effects from those of other caregivers. Additionally, the broader context in which care is provided, vis-à-vis care from mothers and others, may lead to different child outcomes. Here, we examine the effects of paternal care on child growth among Shodagor fisher-traders, where fathers provide high levels of both additive and substitutive care, relative to mothers. We modeled seasonal z-scores and velocities for height, weight, and body mass index (BMI) outcomes using linear mixed models. Our evidence indicates that, as predicted, the context of paternal care is an important predictor of child outcomes. Results show that environmental seasonality and alloparental help contribute to a nuanced understanding of the impact of Shodagor paternal care on child physiology.
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Affiliation(s)
- K E Starkweather
- Department of Anthropology, University of Illinois Chicago, Chicago, Illinois.,Department of Anthropology, University of New Mexico, Albuquerque, New Mexico.,Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - M H Keith
- Department of Anthropology, University of Washington, Seattle, Washington
| | - S P Prall
- Department of Anthropology, University of Missouri, Columbia, Missouri
| | - N Alam
- Health Systems and Population Studies Division, ICDDR,B, Dhaka, Bangladesh
| | - F Zohora
- Health Systems and Population Studies Division, ICDDR,B, Dhaka, Bangladesh
| | - M Emery Thompson
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico
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19
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Page AE, Emmott EH, Myers S. Testing the buffering hypothesis: Breastfeeding problems, cessation, and social support in the UK. Am J Hum Biol 2021; 34:e23621. [PMID: 34056792 DOI: 10.1002/ajhb.23621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/10/2021] [Accepted: 05/14/2021] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVES Physical breastfeeding problems can lead women to terminate breastfeeding earlier than planned. In high-income countries such as the UK, breastfeeding problems have been attributed to the cultural and individual "inexperience" of breastfeeding, ultimately leading to lower breastfeeding rates. Yet, cross-cultural evidence suggests breastfeeding problems still occur in contexts where breastfeeding is common, prolonged, and seen publicly. This suggests breastfeeding problems are not unusual and do not necessarily lead to breastfeeding cessation. As humans evolved to raise children cooperatively, what matters for breastfeeding continuation may be the availability of social support during the postnatal period. Here, we test the hypothesis that social support buffers mothers from the negative impact breastfeeding problems have on duration. METHODS We run Cox models on a sample of 565 UK mothers who completed a retrospective online survey about infant feeding and social support in 2017-2018. RESULTS Breastfeeding problems were important predictors of cessation; however, the direction of the effect was dependent on the problem type and type of support from a range of supporters. Helpful support for discomfort issues (blocked ducts, too much milk) was significantly associated with reduced hazards of cessation, as predicted. However, helpful support for reported milk insufficiency was assoicated with an increased hazard of cessation. CONCLUSIONS Experiencing breastfeeding problems is the norm, but its impact may be mitigated via social support. Working from an interdisciplinary approach, our results highlight that a wide range of supporters who provide different types of support have potential to influence maternal breastfeeding experience.
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Affiliation(s)
- Abigail E Page
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emily H Emmott
- UCL Anthropology, University College London, London, United Kingdom
| | - Sarah Myers
- UCL Anthropology, University College London, London, United Kingdom.,BirthRites Independent Max Planck Research Group, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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20
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Mother’s Partnership Status and Allomothering Networks in the United Kingdom and United States. SOCIAL SCIENCES-BASEL 2021. [DOI: 10.3390/socsci10050182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In high-income, low-fertility (HILF) settings, the mother’s partner is a key provider of childcare. However, it is not clear how mothers without partners draw on other sources of support to raise children. This paper reports the findings from a survey of 1532 women in the United Kingdom and the United States, in which women described who provided childcare for a focal child and how frequently they did so. We use multivariate Bayesian regression models to explore the drivers of support from partners, maternal kin, and other allomothers, as well as the potential impact of allomothering on women’s fertility. Relative to mothers who are in a stable first marriage or cohabitation, mothers who are unpartnered rely more heavily on fewer maternal kin, use more paid help, and have networks which include more non-kin helpers. Repartnered mothers received less help from their partners in the UK and less help from maternal kin in both countries, which US mothers compensated for by relying on other helpers. While repartnered mothers had higher age-adjusted fertility than women in a first partnership, allomaternal support was not clearly related to the mother’s fertility. These findings demonstrate the importance of partners but also of allomothering more broadly in HILF settings.
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21
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Snopkowski K, Nelson JJ. Fertility intentions and outcomes in Indonesia: Evolutionary perspectives on sexual conflict. EVOLUTIONARY HUMAN SCIENCES 2021; 3:e33. [PMID: 37588532 PMCID: PMC10427277 DOI: 10.1017/ehs.2021.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Differential fertility preferences for men and women may provide insights into human sexual conflict. We explore whether pairbonded couples have different preferences for future offspring, which socioecological factors are associated with these preferences, and who achieves their desired fertility over time. We utilise the Indonesia Family Life Survey (IFLS), a longitudinal survey which collected data from 1993 to 2015, to compare desired future fertility for 9655 couples and follow couples who had divergent preferences. The majority of couples (64.8%) want the same number of future offspring. In 20.7% of couples, husbands want more future offspring than their wives, while the reverse occurs in 14.5% of couples. Living in villages with the husband's or the wife's parent(s) is associated with having divergent preferences for future offspring, where there is a higher likelihood that women prefer more offspring than their husbands. When examining fertility outcomes, women, particularly those who marry at older ages, are more likely to achieve their desired preference. Contrary to previous research, we do not find that living near one's natal kin or having increased autonomy increases an individual's likelihood of achieving desired fertility outcomes.
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Affiliation(s)
- Kristin Snopkowski
- Department of Anthropology, 1910 University Drive, Boise State University, Boise, ID83725, USA
| | - James Joseph Nelson
- Department of Anthropology, 1910 University Drive, Boise State University, Boise, ID83725, USA
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