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Butler S. Young people on social media in a globalized world: self-optimization in highly competitive and achievement-oriented forms of life. Front Psychol 2024; 15:1340605. [PMID: 39035080 PMCID: PMC11258645 DOI: 10.3389/fpsyg.2024.1340605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 06/06/2024] [Indexed: 07/23/2024] Open
Abstract
Research investigating young people's social media use has been criticized for its limited theoretical foundations and scope. This paper elaborates young people's social media activity from a socio-ecological evolutionary perspective (SEE), where young people's online exchanges cannot be divorced from the highly competitive and achievement-oriented modern market cultures in which they live. In highly competitive and achievement-oriented forms of life, young people's social media environments are often constituted as dynamic and evolving extrinsically oriented ecological niches that afford for status and identity enhancement while also affording for peer approval, belongingness, and self-worth nested within, and subordinate to, these higher-order affordances. The extrinsic value organization of social media platforms that serve young people's status and identity-enhancement are embodied by a community of mutually interdependent criteria that are evolutionary-based, developmentally salient, and market-driven: physical attractiveness, high (educational and extracurricular) achievements, and material success. Young people's online signaling of these interdependent extrinsic criteria affords for status-allocation and self-enhancement, where each criteria becomes an arena for social competition and identity formation, enabling young people to build personal and optimal models of social success congruent with their own interests and abilities. Young people's status and identity enhancing signaling of these extrinsic criteria is moving toward increasingly idealized or perfect embodiments, informed by accelerating, short-term positive feedback processes that benefit from the technological affordances and densely rewarding peer environments instantiated on social media.
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Affiliation(s)
- Stephen Butler
- Department of Psychology, University of Prince Edward Island, Charlottetown, PE, Canada
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2
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Li S. Racial and Temporal Differences in Fertility-Education Trade-Offs Reveal the Effect of Economic Opportunities on Optimum Family Size in the United States. HUMAN NATURE (HAWTHORNE, N.Y.) 2024; 35:134-152. [PMID: 38801512 DOI: 10.1007/s12110-024-09472-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/10/2024] [Indexed: 05/29/2024]
Abstract
Contemporary trends in low fertility can in part be explained by increasing incentives to invest in offspring's embodied capital over offspring quantity in environments where education is a salient source of social mobility. However, studies on this subject have often neglected to empirically examine heterogeneity, missing out on the opportunity to investigate how this relationship is impacted when individuals are excluded from meaningful participation in economic spheres. Using General Social Survey data from the United States, I examine changes in the relationship between number of siblings and college attendance for White and Black respondents throughout the 1900s. Results show that in the early 1900s, White individuals from larger families had a lower chance of completing four years of college education than those from smaller families, whereas the likelihood for Black individuals was more uniform across family sizes. These racial differences mostly converged in the later part of the century. These results may help explain variations in the timing of demographic transitions within different racial groups in the United States and suggest that the benefits of decreasing family size on educational outcomes may be conditional on the specific economic opportunities afforded to a family.
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Affiliation(s)
- Sally Li
- Department of Anthropology, UCLA, Los Angeles, CA, 90095-1553, USA.
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3
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McFadden C. From the Ground Up: A Multidisciplinary Approach to Past Fertility and Population Narratives. HUMAN NATURE (HAWTHORNE, N.Y.) 2023; 34:476-500. [PMID: 37723407 PMCID: PMC10543153 DOI: 10.1007/s12110-023-09459-x] [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] [Accepted: 08/31/2023] [Indexed: 09/20/2023]
Abstract
Population dynamics form a crucial component of human narratives in the past. Population responses and adaptations not only tell us about the human past but also offer insights into the present and future. Though an area of substantial interest, it is also one of often limited evidence. As such, traditional techniques from demography and anthropology must be adapted considerably to accommodate the available archaeological and ethnohistoric data and an appropriate inferential framework must be applied. In this article, I propose a ground-up, multidisciplinary approach to the study of past population dynamics. Specifically, I develop an empirically informed path diagram based on modern fertility interactions and sources of past environmental, sociocultural, and biological evidence to guide high-resolution case studies. The proposed approach is dynamic and can evolve in response to data inputs as case studies are undertaken. In application, this approach will create new knowledge of past population processes which can greatly enhance our presently limited knowledge of high-frequency, small-scale demographic fluctuations, as well as contribute to our broader understanding of significant population disturbances and change throughout human history.
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Affiliation(s)
- Clare McFadden
- Max Planck Institute for Evolutionary Anthropology, 04103, Leipzig, Germany.
- School of Archaeology and Anthropology, Australian National University, Acton, ACT, 2601, Australia.
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4
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Brandl E, Emmott EH, Mace R. Adoption, Fostering, and Parental Absence in Vanuatu. HUMAN NATURE (HAWTHORNE, N.Y.) 2023; 34:422-455. [PMID: 37642860 PMCID: PMC10543845 DOI: 10.1007/s12110-023-09456-0] [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] [Accepted: 07/28/2023] [Indexed: 08/31/2023]
Abstract
Alloparenting, wherein people provide care to children who are not their biological offspring, is a key aspect of human child-rearing. In the Pacific, many children are adopted or fostered by custodial alloparents even when both biological parents are still alive. From a behavioral ecology perspective, such behaviors are puzzling: why parent someone else's child at your expense? Furthermore, little is known about how these arrangements are made in Pacific Islander societies today, who provides care, and what kinds of outcomes fostered children experience. A better understanding of these proximate factors may help reveal the ultimate drivers behind custodial alloparenting. Here, we report findings from a survey carried out with the caregivers of 282 children in rural areas of Vanuatu, an island nation in Melanesia. Most fostered and adopted children lived with relatives such as aunts, uncles, and grandparents (87.5%) rather than unrelated caregivers, with a strong preference for maternal kin. The most common reasons for these arrangements were that the parents had separated (16.7%), were engaging in labor migration (27.1%), or a combination of both (27.1%). Results for investment in children's education and their educational outcomes were mixed, although children removed from crisis situations did more poorly than children removed for aspirational reasons. Our findings suggest that custodial alloparenting helps families adapt to socioeconomic transitions and changing marriage practices. Outcomes may depend on a range of factors, such as the reason children were transferred out of the natal home to begin with.
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Affiliation(s)
- Eva Brandl
- Lise Meitner Research Group BirthRites, Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, 04103, Leipzig, Germany.
| | - Emily H Emmott
- Department of Anthropology, University College London, London, WC1E 6BT, UK
| | - Ruth Mace
- Department of Anthropology, University College London, London, WC1E 6BT, UK
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5
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Mattison SM, Mattison PM, Beheim BA, Liu R, Blumenfield T, Sum CY, Shenk MK, Seabright E, Alami S. Gender disparities in material and educational resources differ by kinship system. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220299. [PMID: 37381853 PMCID: PMC10291433 DOI: 10.1098/rstb.2022.0299] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 05/14/2023] [Indexed: 06/30/2023] Open
Abstract
Contemporary inequality exists at an unprecedented scale. Social scientists have emphasized the role played by material wealth in driving its escalation. Evolutionary anthropologists understand the drive to accumulate material wealth as one that is coupled ultimately to increasing reproductive success. Owing to biological caps on reproduction for women, the efficiency of this conversion can differ by gender, with implications for understanding the evolution of gender disparities in resource accumulation. Efficiency also differs according to the type of resources used to support reproductive success. In this paper, we review evolutionary explanations of gender disparities in resources and investigate empirical evidence to support or refute those explanations among matrilineal and patrilineal subpopulations of ethnic Chinese Mosuo, who share an ethnolinguistic identity, but differ strikingly in terms of institutions and norms surrounding kinship and gender. We find that gender differentially predicts income and educational attainment. Men were more likely to report income than women; amounts earned were higher for men overall, but the difference between men and women was minimal under matriliny. Men reported higher levels of educational attainment than women, unexpectedly more so in matrilineal contexts. The results reveal nuances in how biology and cultural institutions affect gender disparities in wealth. This article is part of the theme issue 'Evolutionary ecology of inequality'.
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Affiliation(s)
| | - Peter M. Mattison
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Bret A. Beheim
- Human Behavior, Ecology, Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Ruizhe Liu
- Department of Anthropology, University of New Mexico, Albuquerque, NM, USA
| | - Tami Blumenfield
- Department of Anthropology, University of New Mexico, Albuquerque, NM, USA
- School of Ethnology and Sociology, Yunnan University, 2 Cuihu Beilu, Kunming, PRC 650091
| | - Chun-Yi Sum
- College of General Studies, Boston University, Boston, MA, USA
| | - Mary K. Shenk
- Department of Anthropology, Pennsylvania State University, State College, PA, USA
| | - Edmond Seabright
- School of Collective Intelligence, Mohammed VI Polytechnique University, Ben Guerir, Morocco
| | - Sarah Alami
- School of Collective Intelligence, Mohammed VI Polytechnique University, Ben Guerir, Morocco
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6
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Ololade AG, Babalola BI, Omotoso KO, Oyelade OO, Ibrahim EA. Linkages between men's wealth status and the ideal number of children: A trend and multilevel analysis of survey data in Nigeria. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0001036. [PMID: 36972218 PMCID: PMC10042363 DOI: 10.1371/journal.pgph.0001036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 03/03/2023] [Indexed: 03/29/2023]
Abstract
Most African societies practice a patriarchal family system that endows a man with authority and dominance in the family and society with a defined role of being the breadwinner of the home. A man is expected to have a great influence in determining the ideal number of children in the family and take a domineering role in decision-making, especially those related to household resource allocation. Therefore, this study examines the relationship between men's wealth status and an ideal number of children. The study used secondary data from the National Demographic Health Survey (NDHS) from 2003 to 2018. The objectives were achieved using descriptive and inferential statistics, including frequency, mean, ANOVA, and multilevel analysis techniques. Wealth status significantly influenced the ideal number of children considering the crude and adjusted regression analysis. After adjusting for individual-level and contextual factors, the odd ratio of ideal number of children was significantly lower among men in the richest categories of the wealth index. Moreover, men with two wives and above, uneducated men, Northern residents, men living in high community family norms, low community family planning, high community poverty, and low community level of education desired a high number of children. The analyses suggest the need for a consideration of community structures to provide lucrative employment for men and would experience an appreciable fertility decline in line with the objectives and targets stated in Nigeria's population policies and programmes.
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Affiliation(s)
- Adewole G Ololade
- National Centre for Technology Management, Obafemi Awolowo University, Ile-Ife, Nigeria
| | | | - Kehinde O Omotoso
- National Centre for Technology Management, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Oyeyemi O Oyelade
- Department of Nursing Science, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Elhakim A Ibrahim
- The University of Texas at San Antonio, San Antonio, Texas, United States of America
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7
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Schaffnit S, Page AE, Lynch R, Spake L, Sear R, Sosis R, Shaver J, Alam N, Towner M, Shenk MK. The impact of market integration on arranged marriages in Matlab, Bangladesh. EVOLUTIONARY HUMAN SCIENCES 2022; 5:e5. [PMID: 37587939 PMCID: PMC10426007 DOI: 10.1017/ehs.2022.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 12/14/2022] Open
Abstract
Success in marriage markets has lasting impacts on women's wellbeing. By arranging marriages, parents exert financial and social powers to influence spouse characteristics and ensure optimal marriages. While arranging marriages is a major focus of parental investment, marriage decisions are also a source of conflict between parents and daughters in which parents often have more power. The process of market integration may alter parental investment strategies, however, increasing children's bargaining power and reducing parents' influence over children's marriage decisions. We use data from a market integrating region of Bangladesh to (a) describe temporal changes in marriage types, (b) identify which women enter arranged marriages and (c) determine how market integration affects patterns of arranged marriage. Most women's marriages were arranged, with love marriages more recent. We found few predictors of who entered arranged vs. love marriages, and family-level market integration did not predict marriage type at the individual level. However, based on descriptive findings, and findings relating women's and fathers' education to groom characteristics, we argue that at the society-level market integration has opened a novel path in which daughters use their own status, gained via parental investments, to facilitate good marriages under conditions of reduced parental assistance or control.
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Affiliation(s)
| | - A. E. Page
- London School of Hygiene and Tropical Medicine, London, UK
| | - R. Lynch
- Pennsylvania State University, State College, PA, USA
| | - L. Spake
- University of Otago, Dunedin, New Zealand
- Binghamton University, Binghamton, NY, USA
| | - R. Sear
- London School of Hygiene and Tropical Medicine, London, UK
| | - R. Sosis
- University of Connecticut, Storrs, CT, USA
| | - J. Shaver
- University of Otago, Dunedin, New Zealand
| | - N. Alam
- International Centre for Diarrheal Disease Research, Dhaka, Bangladesh
| | - M.C. Towner
- Pennsylvania State University, State College, PA, USA
- Oklahoma State University, Stillwater, OK, USA
| | - M. K. Shenk
- Pennsylvania State University, State College, PA, USA
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8
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Hormonal contraceptives as disruptors of competitive behavior: Theoretical framing and review. Front Neuroendocrinol 2022; 66:101015. [PMID: 35835214 DOI: 10.1016/j.yfrne.2022.101015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/16/2022] [Accepted: 07/06/2022] [Indexed: 12/14/2022]
Abstract
Emerging evidence suggests that hormonal contraceptives (HCs) impact psychological outcomes through alterations in neurophysiology. In this review, we first introduce a theoretical framework for HCs as disruptors of steroid hormone modulation of socially competitive attitudes and behaviors. Then, we comprehensively examine prior research comparing HC users and non-users in outcomes related to competition for reproductive, social, and financial resources. Synthesis of 46 studies (n = 16,290) led to several key conclusions: HC users do not show the same menstrual cycle-related fluctuations in self-perceived attractiveness and some intrasexual competition seen in naturally-cycling women and, further, may show relatively reduced status- or achievement-oriented competitive motivation. However, there a lack of consistent or compelling evidence that HC users and non-users differ in competitive behavior or attitudes for mates or financial resources. These conclusions are tentative given the notable methodological limitations of the studies reviewed. Implications and recommendations for future research are discussed.
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9
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Fertility Dynamics and Life History Tactics Vary by Socioeconomic Position in a Transitioning Cohort of Postreproductive Chilean Women. HUMAN NATURE 2022; 33:83-114. [PMID: 35612730 PMCID: PMC9250487 DOI: 10.1007/s12110-022-09425-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 04/28/2022] [Indexed: 10/26/2022]
Abstract
AbstractGlobally, mortality and fertility rates generally fall as resource abundance increases. This pattern represents an evolutionary paradox insofar as resource-rich ecological contexts can support higher numbers of offspring, a component of biological fitness. This paradox has not been resolved, in part because the relationships between fertility, life history strategies, reproductive behavior, and socioeconomic conditions are complex and cultural-historically contingent. We aim to understand how we might make sense of this paradox in the specific context of late-twentieth-century, mid–demographic transition Chile. We use distribution-specific generalized linear models to analyze associations between fertility-related life-history traits—number of offspring, ages at first and last reproduction, average interbirth interval, and average number of live births per reproductive span year—and socioeconomic position (SEP) using data from a cohort of 6,802 Chilean women born between 1961 and 1970. We show that Chilean women of higher SEP have shorter average interbirth intervals, more births per reproductive span year, later age at first reproduction, earlier ages at last reproduction, and, ultimately, fewer children than women of lower SEP. Chilean women of higher SEP consolidate childbearing over a relatively short time span in the middle of their reproductive careers, whereas women of lower SEP tend to reproduce over the entirety of their reproductive lifespans. These patterns may indicate that different SEP groups follow different pathways toward declining fertility during the demographic transition, reflecting different life-history trade-offs in the process.
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10
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Hyafil A, Baumard N. Evoked and transmitted culture models: Using bayesian methods to infer the evolution of cultural traits in history. PLoS One 2022; 17:e0264509. [PMID: 35389995 PMCID: PMC8989295 DOI: 10.1371/journal.pone.0264509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 02/13/2022] [Indexed: 11/19/2022] Open
Abstract
A central question in behavioral and social sciences is understanding to what extent cultural traits are inherited from previous generations, transmitted from adjacent populations or produced in response to changes in socioeconomic and ecological conditions. As quantitative diachronic databases recording the evolution of cultural artifacts over many generations are becoming more common, there is a need for appropriate data-driven methods to approach this question. Here we present a new Bayesian method to infer the dynamics of cultural traits in a diachronic dataset. Our method called Evoked-Transmitted Cultural model (ETC) relies on fitting a latent-state model where a cultural trait is a latent variable which guides the production of the cultural artifacts observed in the database. The dynamics of this cultural trait may depend on the value of the cultural traits present in previous generations and in adjacent populations (transmitted culture) and/or on ecological factors (evoked culture). We show how ETC models can be fitted to quantitative diachronic or synchronic datasets, using the Expectation-Maximization algorithm, enabling estimating the relative contribution of vertical transmission, horizontal transmission and evoked component in shaping cultural traits. The method also allows to reconstruct the dynamics of cultural traits in different regions. We tested the performance of the method on synthetic data for two variants of the method (for binary or continuous traits). We found that both variants allow reliable estimates of parameters guiding cultural evolution, and that they outperform purely phylogenetic tools that ignore horizontal transmission and ecological factors. Overall, our method opens new possibilities to reconstruct how culture is shaped from quantitative data, with possible application in cultural history, cultural anthropology, archaeology, historical linguistics and behavioral ecology.
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Affiliation(s)
| | - Nicolas Baumard
- Institut d’Etudes Cognitives, Ecole Normale Supérieure, Paris, France
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11
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Mattison SM, Hare D, MacLaren NG, Reynolds AZ, Sum CY, Liu R, Shenk MK, Blumenfield T, Su M, Li H, Wander K. Context Specificity of “Market Integration” among the Matrilineal Mosuo of Southwest China. CURRENT ANTHROPOLOGY 2022. [DOI: 10.1086/719266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Oishi S, Bak H, Caluori N. Cultural psychology of inequality: Current and future directions. ASIAN JOURNAL OF SOCIAL PSYCHOLOGY 2022. [DOI: 10.1111/ajsp.12516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Shigehiro Oishi
- Department of Psychology University of Virginia Charlottesville Virginia USA
| | - Hyeonjin Bak
- Department of Psychology University of Virginia Charlottesville Virginia USA
| | - Nava Caluori
- Department of Psychology University of Virginia Charlottesville Virginia USA
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13
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Life-history tradeoffs in a historical population (1896-1939) undergoing rapid fertility decline: Costs of reproduction? EVOLUTIONARY HUMAN SCIENCES 2022; 4. [DOI: 10.1017/ehs.2022.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Abstract
Evolutionary demographers often invoke tradeoffs between reproduction and survival to explain reductions in fertility during demographic transitions. The evidence for such tradeoffs in humans has been mixed, partly because tradeoffs may be masked by individual differences in quality or access to resources. Unmasking tradeoffs despite such phenotypic correlations requires sophisticated statistical analyses that account for endogeneity among variables and individual differences in access to resources. Here we tested for costs of reproduction using N=13,663 birth records from the maternity hospital in Basel, Switzerland, 1896-1939, a period characterized by rapid fertility declines . We predicted that higher parity is associated with worse maternal and offspring condition at the time of birth, adjusting for age and a variety of covariates. We used Bayesian multivariate, multilevel models to simultaneously analyze multiple related outcomes while accounting for endogeneity, appropriately modeling non-linear effects, dealing with hierarchical data structures, and effectively imputing missing data. Despite all these efforts, we found virtually no evidence for costs of reproduction. Instead, women with better access to resources had fewer children. Barring limitations of the data, these results are consistent with demographic transitions reflecting women's investment in their own embodied capital and/or the adoption of maladaptive low-fertility norms by elites.
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14
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Otterbring T, Folwarczny M, Tan LKL. Populated Places and Conspicuous Consumption: High Population Density Cues Predict Consumers' Luxury-Linked Brand Attitudes. Front Psychol 2021; 12:728903. [PMID: 34925137 PMCID: PMC8673263 DOI: 10.3389/fpsyg.2021.728903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/09/2021] [Indexed: 11/13/2022] Open
Abstract
Population density has been identified as an ecological factor with considerable behavioral implications. The present research aimed to examine whether the mere perception of more (vs. less) populated places can change consumers' luxury-linked brand attitudes. To this end, we experimentally manipulated consumers' perceptions of population density using pictorial exposure to high (vs. low) population density cues. The results revealed a significant interaction between manipulated population density and perceived brand luxury on brand attitudes. Specifically, exposure to high rather than low population density cues resulted in more positive (negative) attitudes toward brands deemed to be more (less) luxurious. These findings support our prediction that high population density cues can shift people's perceptions in consumption contexts linked to luxury. Our work contributes to the growing stream of literature on population density and suggests that this (geo-) demographic factor can exert important downstream effects on consumer behavior.
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Affiliation(s)
- Tobias Otterbring
- Department of Management, University of Agder, Kristiansand, Norway
- Institute of Retail Economics, Stockholm, Sweden
| | - Michał Folwarczny
- Department of Business Administration, Reykjavik University, Reykjavik, Iceland
| | - Lynn K. L. Tan
- School of Social Sciences, Singapore Management University, Singapore, Singapore
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15
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Templon AR, Kirsch DR, Towner MC. Contributions of evolutionary anthropology to understanding climate-induced human migration. Am J Hum Biol 2021; 33:e23635. [PMID: 34212453 PMCID: PMC8365686 DOI: 10.1002/ajhb.23635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 12/17/2022] Open
Abstract
Humans are able to thrive in a multitude of ecological and social environments, including varied environments over an individual lifetime. Migration-leaving one place of residence for another-is a central feature of many people's life histories, and environmental change goes hand-in-hand with migration, both in terms of cause and consequence. Climate change has amplified this connection between environment and migration, with the potential to profoundly impact millions of lives. Although climate-induced migration has been at the forefront of other disciplines in the social sciences, evolutionary anthropologists (EAs) have given it little attention. In this paper we draw upon existing literature and contribute our EA perspective to present a framework for analyzing climate-induced migration that utilizes theoretical approaches from a variety of social science disciplines. We focus on three overlapping dimensions-time, space, and severity-relevant to understanding the impact of climate change on human migration. We apply this framework to case studies from North America of people impacted by climate change and extreme weather events, including hurricanes, droughts, rising sea-levels, and wildfires. We also consider how access to both economic and social resources influence decisions regarding migration. Research focused on climate-induced human migration can benefit equally from the addition of EA perspectives and a more interdisciplinary theoretical approach.
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Affiliation(s)
- Alannah R. Templon
- Department of Integrative BiologyOklahoma State UniversityStillwaterOklahomaUSA
| | - Danielle R. Kirsch
- Department of Integrative BiologyOklahoma State UniversityStillwaterOklahomaUSA
| | - Mary C. Towner
- Department of Integrative BiologyOklahoma State UniversityStillwaterOklahomaUSA
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16
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Butler S. The Development of Market-Driven Identities in Young People: A Socio-Ecological Evolutionary Approach. Front Psychol 2021; 12:623675. [PMID: 34239472 PMCID: PMC8258256 DOI: 10.3389/fpsyg.2021.623675] [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] [Received: 10/30/2020] [Accepted: 05/07/2021] [Indexed: 11/23/2022] Open
Abstract
With the transition toward densely populated and urbanized market-based cultures over the past 200 years, young people's development has been conditioned by the ascendancy of highly competitive skills-based labor markets that demand new forms of embodied capital (e.g., education) for young people to succeed. Life-history analysis reveals parental shifts toward greater investment in fewer children so parents can invest more in their children's embodied capital for them to compete successfully. Concomitantly, the evolution of market-based capitalism has been associated with the rise of extrinsic values such as individualism, materialism and status-seeking, which have intensified over the last 40-50 years in consumer economies. The dominance of extrinsic values is consequential: when young people show disproportionate extrinsic relative to intrinsic values there is increased risk for mental health problems and poorer well-being. This paper hypothesizes that, concomitant with the macro-cultural promotion of extrinsic values, young people in advanced capitalism (AC) are obliged to develop an identity that is market-driven and embedded in self-narratives of success, status, and enhanced self-image. The prominence of extrinsic values in AC are synergistic with neuro-maturational and stage-salient developments of adolescence and embodied in prominent market-driven criterion such as physical attractiveness, displays of wealth and material success, and high (educational and extra-curricular) achievements. Cultural transmission of market-driven criterion is facilitated by evolutionary tendencies in young people to learn from older, successful and prestigious individuals (prestige bias) and to copy their peers. The paper concludes with an integrated socio-ecological evolutionary account of market-driven identities in young people, while highlighting methodological challenges that arise when attempting to bridge macro-cultural and individual development.
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Affiliation(s)
- Stephen Butler
- Department of Psychology, University of Prince Edward Island, Charlottetown, PE, Canada
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17
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Jaeggi AV, Blackwell AD, von Rueden C, Trumble BC, Stieglitz J, Garcia AR, Kraft TS, Beheim BA, Hooper PL, Kaplan H, Gurven M. Do wealth and inequality associate with health in a small-scale subsistence society? eLife 2021; 10:59437. [PMID: 33988506 PMCID: PMC8225390 DOI: 10.7554/elife.59437] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 05/10/2021] [Indexed: 12/11/2022] Open
Abstract
In high-income countries, one’s relative socio-economic position and economic inequality may affect health and well-being, arguably via psychosocial stress. We tested this in a small-scale subsistence society, the Tsimane, by associating relative household wealth (n = 871) and community-level wealth inequality (n = 40, Gini = 0.15–0.53) with a range of psychological variables, stressors, and health outcomes (depressive symptoms [n = 670], social conflicts [n = 401], non-social problems [n = 398], social support [n = 399], cortisol [n = 811], body mass index [n = 9,926], blood pressure [n = 3,195], self-rated health [n = 2523], morbidities [n = 1542]) controlling for community-average wealth, age, sex, household size, community size, and distance to markets. Wealthier people largely had better outcomes while inequality associated with more respiratory disease, a leading cause of mortality. Greater inequality and lower wealth were associated with higher blood pressure. Psychosocial factors did not mediate wealth-health associations. Thus, relative socio-economic position and inequality may affect health across diverse societies, though this is likely exacerbated in high-income countries. Poverty is bad for health. People living in poverty are more likely to struggle to afford nutritious food, lack access to health care, or be overworked or stressed. This may make them susceptible to chronic diseases, contribute to faster aging, and shorten their lifespans. In high-income countries, there is growing evidence to suggest that a person’s ‘rank’ in society also impacts their health. For example, individuals who have a lower position in the social hierarchy report worse health outcomes, regardless of their incomes. But it is unclear why living in an unequal society or having a lower social status contributes to poorer health. One possibility is that inequalities in society are creating a stressful environment that leads to worse physical and mental outcomes. It is thought that this stress largely comes from how humans evolved to prioritize reaching a higher social status over having a long and healthy life. If this is the case, this would mean that the link between social status and health would also be present in non-industrialized communities where social hierarchies tend to be less pronounced. To test this, Jaeggi, Blackwell et al. studied the Indigenous Tsimane population in Bolivia who live in small communities and forage and farm their own food. The income and relative wealth of 870 households from 40 Tsimane communities were compared against various outcomes, including symptoms associated with depression, stress hormone levels, blood pressure, self-rated health and several diseases. Jaeggi, Blackwell et al. found poverty and inequality did not negatively impact all of the health outcomes measured as has been previously reported for industrialized societies. However, blood pressure was higher among people with lower incomes or those who lived in more unequal communities. But because the Tsimane people generally have low blood pressure, the differences were too small to have much effect on their health. People who lived in more unequal communities were also three times more likely to have respiratory infections, but the reason for this was unclear. This shows that social determinants such as a person’s wealth or inequality can affect health, even in communities with less rigid social hierarchies. In industrial societies the effect may be worse in part because they are compounded by lifestyle factors, such as diets rich in fat and sugar, and physical inactivity which can also increase blood pressure. This information may help policy makers reduce health disparities by addressing some of the social determinants of health and the lifestyle factors that cause them.
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Affiliation(s)
- Adrian V Jaeggi
- Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.,Department of Anthropology, Emory University, Atlanta, United States
| | - Aaron D Blackwell
- Department of Anthropology, Washington State University, Pulman, United States
| | | | - Benjamin C Trumble
- School of Human Evolution and Social Change, Arizona State University, Tempe, United States.,Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, United States
| | | | - Angela R Garcia
- Department of Anthropology, Emory University, Atlanta, United States.,School of Human Evolution and Social Change, Arizona State University, Tempe, United States.,Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, United States
| | - Thomas S Kraft
- Department of Anthropology, University of California, Santa Barbara, Santa Barbara, United States
| | - Bret A Beheim
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Paul L Hooper
- Economic Science Institute, Chapman University, Irvine, United States.,Department of Anthropology, University of New Mexico, Albuquerque, United States
| | - Hillard Kaplan
- Economic Science Institute, Chapman University, Irvine, United States
| | - Michael Gurven
- Department of Anthropology, University of California, Santa Barbara, Santa Barbara, United States
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18
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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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Hackman J, Hruschka D. Disentangling wealth effects on fertility in 64 low- and middle-income countries. EVOLUTIONARY HUMAN SCIENCES 2020; 2:e58. [PMID: 37588348 PMCID: PMC10427476 DOI: 10.1017/ehs.2020.62] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Studies have shown mixed associations between wealth and fertility, a finding that has posed ongoing puzzles for evolutionary theories of human reproduction. However, measures of wealth do not simply capture economic capacity, which is expected to increase fertility. They can also serve as a proxy for market opportunities available to a household, which may reduce fertility. The multifaceted meaning of many wealth measures obscures our ability to draw inferences about the relationship between wealth and fertility. Here, we disentangle economic capacity and market opportunities using wealth measures that do not carry the same market-oriented biases as commonly used asset-based measures. Using measures of agricultural and market-based wealth for 562,324 women across 111,724 sampling clusters from 151 DHS surveys in 64 countries, we employ a latent variable structural equation model to estimate (a) latent variables capturing economic capacity and market opportunity and (b) their effects on completed fertility. Market opportunities had a consistent negative effect on fertility, while economic capacity had a weaker but generally positive effect on fertility. The results show that the confusion between operational measures of wealth and the concepts of economic capacity can impede our understanding of how material resources and market contexts shape reproduction.
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Affiliation(s)
- Joseph Hackman
- University of Utah, Department of Anthropology, Salt Lake City, Utah, USA
| | - Daniel Hruschka
- Arizona State University, School of Human Evolution and Social Change, Arizona, USA
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21
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Garfield ZH, Syme KL, Hagen EH. Universal and variable leadership dimensions across human societies. EVOL HUM BEHAV 2020. [DOI: 10.1016/j.evolhumbehav.2020.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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von Rueden C. Making and unmaking egalitarianism in small-scale human societies. Curr Opin Psychol 2020; 33:167-171. [DOI: 10.1016/j.copsyc.2019.07.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 07/20/2019] [Indexed: 11/28/2022]
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23
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Samuni L, Tkaczynski P, Deschner T, Löhrrich T, Wittig RM, Crockford C. Maternal effects on offspring growth indicate post-weaning juvenile dependence in chimpanzees ( Pan troglodytes verus). Front Zool 2020; 17:1. [PMID: 31911809 PMCID: PMC6945487 DOI: 10.1186/s12983-019-0343-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In animals with altricial offspring, most growth occurs after birth and may be optimized by post-natal maternal care. Maternal effects on growth may be influenced by individual characteristics of the mothers, such as social status, individual investment strategies and the length of association with offspring. The prolonged juvenile dependence seen in humans is a distinctive life history adaptation, which may have evolved to facilitate sustained somatic and brain growth.In chimpanzees, offspring are typically weaned at approximately 4 years old, yet immature individuals continue to associate with their mothers for up to 10 years beyond weaning. Whether this lengthy association or the individual characteristics of mothers influences growth patterns in this species is not clear.The relationship between urinary creatinine and specific gravity is an established non-invasive measure of muscle mass in humans and chimpanzees. We analysed the urinary creatinine and specific gravity of 1318 urine samples from 70 wild chimpanzees from the Taï Forest, Ivory Coast aged 4 to 15 years. RESULTS We showed a clear increase in urinary creatinine levels with age in both males and females, replicating established growth curves in this species and reaffirming this measure as a reliable proxy for lean body mass. Comparing those who experience maternal loss (orphans) with non-orphan chimpanzees, maternal presence beyond weaning age and into late juvenility positively influenced offspring muscle mass throughout ontogeny such that orphans had significantly less muscle mass than age-matched non-orphans. In age-matched offspring with mothers, those with high-ranking mothers had greater muscle mass. Accounting for variation in muscle mass attributable to maternal presence, we found no effect of maternal investment (length of inter birth interval, from own birth to birth of following sibling) on offspring muscle mass. CONCLUSION Chimpanzee mothers have an extended and multi-faceted influence on offspring phenotypes. Our results suggest that maternal investment extends beyond lactation and into early adulthood and has clear benefits to offspring physical development. Therefore, prolonged juvenile dependence, although unique in its form in human societies, may be a trait with deeper evolutionary origins.
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Affiliation(s)
- Liran Samuni
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
- Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques, Abidjan, Ivory Coast
- Department of Human Evolutionary Biology, Harvard University, Cambridge, UK
| | - Patrick Tkaczynski
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Tobias Deschner
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Therese Löhrrich
- World Wide Fund for Nature, Dzanga Sangha Protected Areas, Bangui, Central African Republic
- Epidemiology of Highly Pathogenic Microorganisms, Robert Koch Institute, Berlin, Germany
| | - Roman M. Wittig
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
- Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques, Abidjan, Ivory Coast
| | - Catherine Crockford
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
- Taï Chimpanzee Project, Centre Suisse de Recherches Scientifiques, Abidjan, Ivory Coast
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Breastfeeding Duration and the Social Learning of Infant Feeding Knowledge in Two Maya Communities. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2020; 31:43-67. [DOI: 10.1007/s12110-019-09358-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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25
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Goetz CD, Pillsworth EG, Buss DM, Conroy-Beam D. Evolutionary Mismatch in Mating. Front Psychol 2019; 10:2709. [PMID: 31866904 PMCID: PMC6904347 DOI: 10.3389/fpsyg.2019.02709] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/15/2019] [Indexed: 01/31/2023] Open
Abstract
Evolutionary mismatch concepts are being fruitfully employed in a number of research domains, including medicine, health, and human cognition and behavior to generate novel hypotheses and better understand existing findings. We contend that research on human mating will benefit from explicitly addressing both the evolutionary mismatch of the people we study and the evolutionary mismatch of people conducting the research. We identified nine mismatch characteristics important to the study of human mating and reviewed the literature related to each of these characteristics. Many of the people we study are: exposed to social media, in temporary relationships, relocatable, autonomous in their mating decisions, nulliparous, in groups that are socially segmented, in an educational setting, confronted with lots of options, and young. We applied mismatch concepts to each characteristic to illustrate the importance of incorporating mismatch into this research area. Our aim in this paper is not to identify all potential mismatch effects in mating research, nor to challenge or disqualify existing data. Rather, we demonstrate principled ways of thinking about evolutionary mismatch in order to propel progress in mating research. We show how attending to the potential effects of mismatch can help us refine our theoretical and methodological approaches and deepen our understanding of existing patterns in the empirical record. We conclude with specific recommendations about how to include consideration of evolutionary mismatch into research on human mating.
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Affiliation(s)
- Cari D. Goetz
- Department of Psychology, California State University, San Bernardino, San Bernardino, CA, United States
| | - Elizabeth G. Pillsworth
- Division of Anthropology, Evolutionary Anthropology Program, California State University, Fullerton, Fullerton, CA, United States
| | - David M. Buss
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States
| | - Daniel Conroy-Beam
- Department of Psychological & Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
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26
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Worthman CM, Trang K. Dynamics of body time, social time and life history at adolescence. Nature 2018; 554:451-457. [PMID: 29469099 DOI: 10.1038/nature25750] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/15/2018] [Indexed: 12/16/2022]
Abstract
Recent opposing trends towards earlier physical maturation and later social maturation present a conundrum of apparent biological-social mismatch. Here we use life history analysis from evolutionary ecology to identify forces that drive these shifts. Together with findings in developmental science, our life history analysis indicates that adolescence is a distinctive period for biological embedding of culture. Ethnographic evidence shows that mass education is a novel feature of the globalizing cultural configurations of adolescence, which are driven by transformations in labour, livelihood and lifestyle. Evaluation of the life history trade-offs and sociocultural ecologies that are experienced by adolescents may offer a practical basis for enhancing their development.
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Affiliation(s)
- Carol M Worthman
- 1Department of Anthropology, Emory University, Atlanta, Georgia 30322, USA
| | - Kathy Trang
- 1Department of Anthropology, Emory University, Atlanta, Georgia 30322, USA
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27
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Colleran H, Snopkowski K. Variation in wealth and educational drivers of fertility decline across 45 countries. POPUL ECOL 2018. [DOI: 10.1007/s10144-018-0626-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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28
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Abstract
Fitness is always relative to the fitness of others in the group or breeding population. Even in very low-fertility societies, individual fitness as measured by the share of genes in subsequent generations may still be maximized. Further, sexual selection theory from evolutionary biology suggests that the relationship between status and fertility will differ for males and females. For this reason it is important to examine the relationship between status and fertility separately for males and females-something few demographic studies of fertility do. When male fertility is measured separately, high-status men (as measured by their wealth and personal income) have higher fertility than low-status men, even in very low-fertility societies, so individual males appear to be maximizing their fitness within the constraints posed by a modern society. Thus male fertility cannot be considered maladaptive. When female fertility is measured separately, in both very high- and very low-fertility societies, there is not much variance across women of different statuses in completed fertility. Only in societies currently changing rapidly (with falling fertility rates) is somewhat high variance across women of different statuses in completed fertility found. What is seen across all phases of the demographic transition appears to be a continuation of two somewhat different evolved human reproductive strategies-one male, one female-in changing social and material contexts. Whether contemporary female fertility is maladaptive remains an open question.
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Demographic studies enhance the understanding of evolutionarily (mal)adaptive behaviors and phenomena in humans: a review on fertility decline and an integrated model. POPUL ECOL 2017. [DOI: 10.1007/s10144-017-0597-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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30
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Stulp G, Barrett L. Wealth, fertility and adaptive behaviour in industrial populations. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150153. [PMID: 27022080 DOI: 10.1098/rstb.2015.0153] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2015] [Indexed: 11/12/2022] Open
Abstract
The lack of association between wealth and fertility in contemporary industrialized populations has often been used to question the value of an evolutionary perspective on human behaviour. Here, we first present the history of this debate, and the evolutionary explanations for why wealth and fertility (the number of children) are decoupled in modern industrial settings. We suggest that the nature of the relationship between wealth and fertility remains an open question because of the multi-faceted nature of wealth, and because existing cross-sectional studies are ambiguous with respect to how material wealth and fertility are linked. A literature review of longitudinal studies on wealth and fertility shows that the majority of these report positive effects of wealth, although levels of fertility seem to fall below those that would maximize fitness. We emphasize that reproductive decision-making reflects a complex interplay between individual and societal factors that resists simple evolutionary interpretation, and highlight the role of economic insecurity in fertility decisions. We conclude by discussing whether the wealth-fertility relationship can inform us about the adaptiveness of modern fertility behaviour, and argue against simplistic claims regarding maladaptive behaviour in humans.
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Affiliation(s)
- Gert Stulp
- Department of Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Louise Barrett
- Department of Psychology, University of Lethbridge, Lethbridge, Alberta, Canada T1 K 3M4
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31
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Lawson DW, Borgerhoff Mulder M. The offspring quantity-quality trade-off and human fertility variation. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150145. [PMID: 27022072 PMCID: PMC4822425 DOI: 10.1098/rstb.2015.0145] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2016] [Indexed: 11/12/2022] Open
Abstract
The idea that trade-offs between offspring quantity and quality shape reproductive behaviour has long been central to economic perspectives on fertility. It also has a parallel and richer theoretical foundation in evolutionary ecology. We review the application of the quantity–quality trade-off concept to human reproduction, emphasizing distinctions between clutch size and lifetime fertility, and the wider set of forces contributing to fertility variation in iteroparous and sexually reproducing species like our own. We then argue that in settings approximating human evolutionary history, several factors limit costly sibling competition. Consequently, while the optimization of quantity–quality trade-offs undoubtedly shaped the evolution of human physiology setting the upper limits of reproduction, we argue it plays a modest role in accounting for socio-ecological and individual variation in fertility. Only upon entering the demographic transition can fertility limitation be clearly interpreted as strategically orientated to advancing offspring quality via increased parental investment per child, with low fertility increasing descendant socio-economic success, although not reproductive success. We conclude that existing economic and evolutionary literature has often overemphasized the centrality of quantity–quality trade-offs to human fertility variation and advocate for the development of more holistic frameworks encompassing alternative life-history trade-offs and the evolved mechanisms guiding their resolution.
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Affiliation(s)
- David W Lawson
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, UK
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32
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von Rueden CR, Jaeggi AV. Men's status and reproductive success in 33 nonindustrial societies: Effects of subsistence, marriage system, and reproductive strategy. Proc Natl Acad Sci U S A 2016; 113:10824-9. [PMID: 27601650 PMCID: PMC5047206 DOI: 10.1073/pnas.1606800113] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Social status motivates much of human behavior. However, status may have been a relatively weak target of selection for much of human evolution if ancestral foragers tended to be more egalitarian. We test the "egalitarianism hypothesis" that status has a significantly smaller effect on reproductive success (RS) in foragers compared with nonforagers. We also test between alternative male reproductive strategies, in particular whether reproductive benefits of status are due to lower offspring mortality (parental investment) or increased fertility (mating effort). We performed a phylogenetic multilevel metaanalysis of 288 statistical associations between measures of male status (physical formidability, hunting ability, material wealth, political influence) and RS (mating success, wife quality, fertility, offspring mortality, and number of surviving offspring) from 46 studies in 33 nonindustrial societies. We found a significant overall effect of status on RS (r = 0.19), though this effect was significantly lower than for nonhuman primates (r = 0.80). There was substantial variation due to marriage system and measure of RS, in particular status associated with offspring mortality only in polygynous societies (r = -0.08), and with wife quality only in monogamous societies (r = 0.15). However, the effects of status on RS did not differ significantly by status measure or subsistence type: foraging, horticulture, pastoralism, and agriculture. These results suggest that traits that facilitate status acquisition were not subject to substantially greater selection with domestication of plants and animals, and are part of reproductive strategies that enhance fertility more than offspring well-being.
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Affiliation(s)
| | - Adrian V Jaeggi
- Department of Anthropology, Emory University, Atlanta, GA 30316
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Abstract
Cultural evolutionists have long been interested in the problem of why fertility declines as populations develop. By outlining plausible mechanistic links between individual decision-making, information flow in populations and competition between groups, models of cultural evolution offer a novel and powerful approach for integrating multiple levels of explanation of fertility transitions. However, only a modest number of models have been published. Their assumptions often differ from those in other evolutionary approaches to social behaviour, but their empirical predictions are often similar. Here I offer the first overview of cultural evolutionary research on demographic transition, critically compare it with approaches taken by other evolutionary researchers, identify gaps and overlaps, and highlight parallel debates in demography. I suggest that researchers divide their labour between three distinct phases of fertility decline--the origin, spread and maintenance of low fertility--each of which may be driven by different causal processes, at different scales, requiring different theoretical and empirical tools. A comparative, multi-level and mechanistic framework is essential for elucidating both the evolved aspects of our psychology that govern reproductive decision-making, and the social, ecological and cultural contingencies that precipitate and sustain fertility decline.
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Affiliation(s)
- Heidi Colleran
- Institute for Advanced Study in Toulouse, 21 allee de Brienne, Toulouse 30151, France
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35
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Snopkowski K, Towner MC, Shenk MK, Colleran H. Pathways from education to fertility decline: a multi-site comparative study. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150156. [PMID: 27022083 PMCID: PMC4822436 DOI: 10.1098/rstb.2015.0156] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2016] [Indexed: 11/12/2022] Open
Abstract
Women's education has emerged as a central predictor of fertility decline, but the many ways that education affects fertility have not been subject to detailed comparative investigation. Taking an evolutionary biosocial approach, we use structural equation modelling to examine potential pathways between education and fertility including: infant/child mortality, women's participation in the labour market, husband's education, social network influences, and contraceptive use or knowledge across three very different contexts: Matlab, Bangladesh; San Borja, Bolivia; and rural Poland. Using a comparable set of variables, we show that the pathways by which education affects fertility differ in important ways, yet also show key similarities. For example, we find that across all three contexts, education is associated with delayed age at first birth via increasing women's labour-force participation, but this pathway only influences fertility in rural Poland. In Matlab and San Borja, education is associated with lower local childhood mortality, which influences fertility, but this pathway is not important in rural Poland. Similarities across sites suggest that there are common elements in how education drives demographic transitions cross-culturally, but the differences suggest that local socioecologies also play an important role in the relationship between education and fertility decline.
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Affiliation(s)
- Kristin Snopkowski
- Department of Anthropology, Boise State University, 1910 University Drive, Boise, ID 83725, USA
| | - Mary C Towner
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Mary K Shenk
- Department of Anthropology, University of Missouri, Columbia, MO 65211, USA
| | - Heidi Colleran
- Institute for Advanced Study in Toulouse, Toulouse School of Economics, Toulouse 31015, France
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36
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Sear R, Lawson DW, Kaplan H, Shenk MK. Understanding variation in human fertility: what can we learn from evolutionary demography? Philos Trans R Soc Lond B Biol Sci 2016; 371:20150144. [PMID: 27022071 PMCID: PMC4822424 DOI: 10.1098/rstb.2015.0144] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2016] [Indexed: 01/09/2023] Open
Abstract
Decades of research on human fertility has presented a clear picture of how fertility varies, including its dramatic decline over the last two centuries in most parts of the world. Why fertility varies, both between and within populations, is not nearly so well understood. Fertility is a complex phenomenon, partly physiologically and partly behaviourally determined, thus an interdisciplinary approach is required to understand it. Evolutionary demographers have focused on human fertility since the 1980s. The first wave of evolutionary demographic research made major theoretical and empirical advances, investigating variation in fertility primarily in terms of fitness maximization. Research focused particularly on variation within high-fertility populations and small-scale subsistence societies and also yielded a number of hypotheses for why fitness maximization seems to break down as fertility declines during the demographic transition. A second wave of evolutionary demography research on fertility is now underway, paying much more attention to the cultural and psychological mechanisms underpinning fertility. It is also engaging with the complex, multi-causal nature of fertility variation, and with understanding fertility in complex modern and transitioning societies. Here, we summarize the history of evolutionary demographic work on human fertility, describe the current state of the field, and suggest future directions.
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Affiliation(s)
- Rebecca Sear
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - David W Lawson
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Hillard Kaplan
- Department of Anthropology, University of New Mexico, Albuquerque, NM, USA
| | - Mary K Shenk
- Department of Anthropology and Life Sciences & Society Program, University of Missouri, Columbia, MO, USA
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