Grandparental Investment

2021 ◽  
pp. 410-435
Author(s):  
Paula Sheppard
Keyword(s):  
Life History ◽  
Breeding System ◽  
Social Factors ◽  
Cooperative Breeding ◽  
Inclusive Fitness ◽  
Human Life ◽  
Adaptive Strategy ◽  
Ecological Framework ◽  
Grandparental Investment

This chapter assesses the alloparental role that grandparents play in the human cooperative breeding system. Grandparenthood is an intriguing phenomenon and a fascinating chapter in the extraordinary human life-history story. Grandparental investment is well-defined as an adaptive strategy that enhances inclusive fitness. Although there is great diversity in grandparenting practices across human cultures, the evidence clearly demonstrates that grandparents help, and that that help is beneficial to the whole fitness unit. By applying an evolutionary ecological framework to understanding how differential grandparental solicitude emerges, and by understanding that these differences depend on genetic, ecological, and social factors, predictable patterns of investment can be derived.

scholarly journals Inclusive fitness and differential productivity across the life course determine intergenerational transfers in a small-scale human society

2015 ◽  
Vol 282 (1803) ◽  
pp. 20142808 ◽  
Author(s):  
Paul L. Hooper ◽  
Michael Gurven ◽  
Jeffrey Winking ◽  
Hillard S. Kaplan
Keyword(s):  
Life History ◽  
Inclusive Fitness ◽  
Human Life ◽  
Intergenerational Transfers ◽  
Essential Element ◽  
Life History Evolution ◽  
Small Scale ◽  
Human Society ◽  
Extended Lifespan ◽  
The Life Course

Transfers of resources between generations are an essential element in current models of human life-history evolution accounting for prolonged development, extended lifespan and menopause. Integrating these models with Hamilton's theory of inclusive fitness, we predict that the interaction of biological kinship with the age-schedule of resource production should be a key driver of intergenerational transfers. In the empirical case of Tsimane’ forager–horticulturalists in Bolivian Amazonia, we provide a detailed characterization of net transfers of food according to age, sex, kinship and the net need of donors and recipients. We show that parents, grandparents and siblings provide significant net downward transfers of food across generations. We demonstrate that the extent of provisioning responds facultatively to variation in the productivity and demographic composition of families, as predicted by the theory. We hypothesize that the motivation to provide these critical transfers is a fundamental force that binds together human nuclear and extended families. The ubiquity of three-generational families in human societies may thus be a direct reflection of fundamental evolutionary constraints on an organism's life-history and social organization.

scholarly journals Inclusive-fitness logic of cooperative breeding with benefits of natal philopatry

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130361 ◽  
Author(s):  
Geoff Wild ◽  
Cody Koykka
Keyword(s):  
Computer Simulation ◽  
Life History ◽  
Cooperative Breeding ◽  
Inclusive Fitness ◽  
Social Groups ◽  
Reproductive Skew ◽  
Natal Philopatry ◽  
Evolutionary Transition ◽  
Model Predictions ◽  
Cooperatively Breeding

In cooperatively breeding species, individuals help to raise offspring that are not their own. We use two inclusive-fitness models to study the advantage of this kind of helpful behaviour in social groups with high reproductive skew. Our first model does not allow for competition among relatives to occur but our second model does. Specifically, our second model assumes a competitive hierarchy among nest-mates, with non-breeding helpers ranked higher than their newborn siblings. For each model, we obtain an expression for the change in inclusive fitness experienced by a helpful individual in a selfish population. The prediction suggested by each expression is confirmed with computer simulation. When model predictions are compared to one another, we find that helping emerges under a broader range of conditions in the second model. Although competition among kin occurs in our second model, we conclude that the life-history features associated with this competition also act to promote the evolutionary transition from solitary to cooperative breeding.

scholarly journals The Life History of Learning Subsistence Skills among Hadza and BaYaka Foragers from Tanzania and the Republic of Congo

Human Nature ◽  
2021 ◽  
Author(s):  
Sheina Lew-Levy ◽  
Erik J. Ringen ◽  
Alyssa N. Crittenden ◽  
Ibrahim A. Mabulla ◽  
Tanya Broesch ◽  
...  
Keyword(s):  
Life History ◽  
Task Difficulty ◽  
Human Life ◽  
Age Of Acquisition ◽  
Cross Cultural ◽  
Cultural Variation ◽  
Republic Of Congo ◽  
Cross Cultural Differences ◽  
History Of ◽  
The Republic

AbstractAspects of human life history and cognition, such as our long childhoods and extensive use of teaching, theoretically evolved to facilitate the acquisition of complex tasks. The present paper empirically examines the relationship between subsistence task difficulty and age of acquisition, rates of teaching, and rates of oblique transmission among Hadza and BaYaka foragers from Tanzania and the Republic of Congo. We further examine cross-cultural variation in how and from whom learning occurred. Learning patterns and community perceptions of task difficulty were assessed through interviews. We found no relationship between task difficulty, age of acquisition, and oblique transmission, and a weak but positive relationship between task difficulty and rates of teaching. While same-sex transmission was normative in both societies, tasks ranked as more difficult were more likely to be transmitted by men among the BaYaka, but not among the Hadza, potentially reflecting cross-cultural differences in the sexual division of subsistence and teaching labor. Further, the BaYaka were more likely to report learning via teaching, and less likely to report learning via observation, than the Hadza, possibly owing to differences in socialization practices.

Language and life history: A new perspective on the development and evolution of human language

2006 ◽  
Vol 29 (3) ◽  
pp. 259-280 ◽  
Author(s):  
John L. Locke ◽  
Barry Bogin
Keyword(s):  
Life History ◽  
Adult Development ◽  
Homo Sapiens ◽  
Human Life ◽  
Modern Human ◽  
Linguistic Knowledge ◽  
Human Language ◽  
Juvenile Period ◽  
Development Of Language ◽  
New Perspective

It has long been claimed that Homo sapiens is the only species that has language, but only recently has it been recognized that humans also have an unusual pattern of growth and development. Social mammals have two stages of pre-adult development: infancy and juvenility. Humans have two additional prolonged and pronounced life history stages: childhood, an interval of four years extending between infancy and the juvenile period that follows, and adolescence, a stage of about eight years that stretches from juvenility to adulthood. We begin by reviewing the primary biological and linguistic changes occurring in each of the four pre-adult ontogenetic stages in human life history. Then we attempt to trace the evolution of childhood and juvenility in our hominin ancestors. We propose that several different forms of selection applied in infancy and childhood; and that, in adolescence, elaborated vocal behaviors played a role in courtship and intrasexual competition, enhancing fitness and ultimately integrating performative and pragmatic skills with linguistic knowledge in a broad faculty of language. A theoretical consequence of our proposal is that fossil evidence of the uniquely human stages may be used, with other findings, to date the emergence of language. If important aspects of language cannot appear until sexual maturity, as we propose, then a second consequence is that the development of language requires the whole of modern human ontogeny. Our life history model thus offers new ways of investigating, and thinking about, the evolution, development, and ultimately the nature of human language.

scholarly journals Accurate age estimation in small-scale societies

2017 ◽  
Vol 114 (31) ◽  
pp. 8205-8210 ◽  
Author(s):  
Yoan Diekmann ◽  
Daniel Smith ◽  
Pascale Gerbault ◽  
Mark Dyble ◽  
Abigail E. Page ◽  
...  
Keyword(s):  
Life History ◽  
Bayesian Approach ◽  
Age Estimation ◽  
Human Life ◽  
The Philippines ◽  
Monte Carlo Algorithm ◽  
Small Scale ◽  
Hunter Gatherers ◽  
Cultural Life ◽  
Ranking Order

Precise estimation of age is essential in evolutionary anthropology, especially to infer population age structures and understand the evolution of human life history diversity. However, in small-scale societies, such as hunter-gatherer populations, time is often not referred to in calendar years, and accurate age estimation remains a challenge. We address this issue by proposing a Bayesian approach that accounts for age uncertainty inherent to fieldwork data. We developed a Gibbs sampling Markov chain Monte Carlo algorithm that produces posterior distributions of ages for each individual, based on a ranking order of individuals from youngest to oldest and age ranges for each individual. We first validate our method on 65 Agta foragers from the Philippines with known ages, and show that our method generates age estimations that are superior to previously published regression-based approaches. We then use data on 587 Agta collected during recent fieldwork to demonstrate how multiple partial age ranks coming from multiple camps of hunter-gatherers can be integrated. Finally, we exemplify how the distributions generated by our method can be used to estimate important demographic parameters in small-scale societies: here, age-specific fertility patterns. Our flexible Bayesian approach will be especially useful to improve cross-cultural life history datasets for small-scale societies for which reliable age records are difficult to acquire.

The Evolution of Human Infancy: Why It Helps to Be Helpless

2021 ◽  
Vol 50 (1) ◽  
Author(s):  
Karen R. Rosenberg
Keyword(s):  
Life History ◽  
Material Culture ◽  
Cultural Adaptation ◽  
Human Life ◽  
Developmental State ◽  
Annual Review ◽  
Publication Date ◽  
Cultural Adaptations ◽  
Social And Emotional ◽  
Emotional Relationships

Humans have a prolonged childhood, which begins with an immature developmental state at birth. We take care of these helpless infants through a variety of cultural adaptations, including material culture, provisioning of food, and shared child care. Our species has long been characterized as having secondary altriciality, but an examination of human life history shows that we are fundamentally precocial, despite seeming helpless at birth. Human babies are also relatively large and overall require substantial attention and energy from caregivers. Previous work has focused on how culture permits us to give birth to helpless young and how our cultural adaptation solves problems stemming from encephalization. The birth of these dependent, costly creatures poses challenges but also creates opportunities by enhancing the development of social and emotional relationships with caregivers as well as language acquisition and enculturation. Expected final online publication date for the Annual Review of Anthropology, Volume 50 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Evolution of Human Life History

2020 ◽  
pp. 753-767
Author(s):  
B. Bogin ◽  
C. Varea
Keyword(s):  
Life History ◽  
Human Life

scholarly journals Age-Appropriate Wisdom? Ethnobiological Knowledge Ontogeny in Pastoralist Mexican Choyeros

2021 ◽  
Author(s):  
Eric Schniter ◽  
Shane Macfarlan ◽  
Juan J. Garcia ◽  
Gorgonio Ruiz‑Campos ◽  
Diego Guevara Beltran ◽  
...  
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Assessment Tool ◽  
Human Life ◽  
Early Adulthood ◽  
Knowledge Assessment ◽  
Baja California Sur ◽  
Age Appropriate ◽  
Age And Sex ◽  
Embodied Capital

We investigate whether age profiles of ethnobiological knowledge developmentare consistent with predictions derived from life history theory about the timing ofproductivity and reproduction. Life history models predict complementary knowledgeprofiles developing across the lifespan for women and men as they experiencechanges in embodied capital and the needs of dependent offspring. We evaluatethese predictions using an ethnobiological knowledge assessment tool developedfor an off-grid pastoralist population known as Choyeros, from Baja California Sur,Mexico. Our results indicate that while individuals acquire knowledge of most dangerousitems and edible resources by early adulthood, knowledge of plants and animalsrelevant to the age and sex divided labor domains and ecologies (e.g., women’shouse gardens, men’s herding activities in the wilderness) continues to develop intomiddle adulthood but to different degrees and at different rates for men and women.As the demands of offspring on parents accumulate with age, reproductive-agedadults continue to develop their knowledge to meet their children’s needs. After controllingfor vision, our analysis indicates that many post-reproductive adults showthe greatest ethnobiological knowledge. These findings extend our understanding ofthe evolved human life history by illustrating how changes in embodied capital andthe needs of dependent offspring predict the development of men’s and women’sethnobiological knowledge across the lifespan.

scholarly journals Mujeres y hombres. Desigualdades de género en el contexto mexicanoWomen and men. Gender inequalities in the Mexican context

2014 ◽  
Vol 22 (44) ◽  
Author(s):  
Francisco José Zamudio Sánchez ◽  
María Del Rosario Ayala Carrillo ◽  
Roxana Ivette Arana Ovalle
Keyword(s):  
Policy Change ◽  
Social Factors ◽  
Human Life ◽  
National Level ◽  
Living Conditions ◽  
Harmonic Mean ◽  
Gender Inequalities ◽  
Men And Women ◽  
Las Mujeres ◽  
Cultural Constructions

Las construcciones socioculturales sobre género permean todas las esferas de la vida humana generando diversas inequidades. Es necesario medirlas y proponer alternativas de solución o modificación de políticas que las atiendan. Usando una media harmónica sobre las condiciones en las que viven mujeres y hombres, se midieron atributos de once factores sociales disponibles a escala nacional. Los atributos fueron jerarquizados para cuantificar el diferencial en el cual estos factores se encuentran. No únicamente las mujeres están en condiciones de inequidad, aunque son más frecuentes y graves. Políticas públicas en seis factores deben atender, prioritariamente, a las mujeres y en cinco a los hombres. En cada factor identificamos los atributos más inequitativos para hacer posible la instrumentación de acciones pertinentes. Así, el diseño de las políticas, desde la planeación, cuenta con posibilidades de actuar en congruencia con las necesidades. Abstract Cultural constructions of gender permeate all areas of human life, generating diverse inequities. This requires knowledge of the situations in which men and women are in a particular one and, accordingly, propose solutions or policy change that pay attention to such inequities. Using a harmonic mean on the living conditions in which women and men are, attributes of eleven social factors were measured, available at national level. Such attributes were analytically nested to quantify the differential in which these factors are. Not only women are in inequity conditions, although they are more frequent and severe. Public policies in six factors should attend, mainly, to women and in five to men. We identified, inside each factor, the attributes with more inequity to make possible the implementation of appropriate actions. The corresponding design of policies has, from planning, possibilities of acting in line with the needs.

scholarly journals The welsh Welsh - Y Cymry cymreig: A study of cultural exclusion among ruraldwelling older people using a critical human ecological framework

2018 ◽  
Vol 12 (2) ◽  
pp. 119-151 ◽  
Author(s):  
Bethan Winter ◽  
Vanessa Burholt
Keyword(s):  
Life History ◽  
Older People ◽  
Rural Areas ◽  
Population Change ◽  
Ecological Framework ◽  
Comparison Theory ◽  
Family Structures ◽  
Documentary Sources ◽  
Period Effects ◽  
South Wales

Research on cultural exclusion has not kept apace with transformations to rural populations, economy, family structures and community relationships. Cultural exclusion refers to the extent to which people are able or willing to conform to cultural norms and values. We theorise cultural exclusion using the critical human ecological framework and social comparison theory, taking into account period effects, area effects and cohort and/or lifecourse effects. Qualitative case studies in three rural areas of South Wales (United Kingdom) synthesise data from life-history interviews, life-history calendars, documentary sources and focus groups (n = 56). Our findings suggest that cultural exclusion is an issue for rural-dwelling older people, which they describe by temporal self-comparison and group comparisons. The critical human ecological framework provides new insight into the drivers (industrial decline, policy and population change, a shift from collectivism to individualism), and outcomes (sense of belonging, community cohesion) of cultural exclusion experienced by rural-dwelling older people.

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