Human Kinship Systems Research Articles

The Roots of Science, Technology, Engineering, and Mathematics: What Are the Evolutionary and Neural Bases of Human Mathematics and Technology?

Introduction: Neural exaptations represent descent via transitions to novel neural functions. A primary transition in human cognitive and neural evolution was from a predominantly socially oriented primate brain to a brain that also instantiates and subserves science, technology, and engineering, all of which depend on mathematics. Upon what neural substrates and upon what evolved cognitive mechanisms did human capacities for science, technology, engineering, and mathematics (STEM), and especially its mathematical underpinnings, emerge? Previous theory focuses on roles for tools, language, and arithmetic in the cognitive origins of STEM, but none of these factors appears sufficient to support the transition. Methods: In this article, I describe and evaluate a novel hypothesis for the neural origins and substrates of STEM-based cognition: that they are based in human kinship systems and human maximizing of inclusive fitness. Results: The main evidence for this hypothesis is threefold. First, as demonstrated by anthropologists, human kinship systems exhibit complex mathematical and geometrical structures that function under sets of explicit rules, and such systems and rules pervade and organize all human cultures. Second, human kinship underlies the core algebraic mechanism of evolution, maximization of inclusive fitness, quantified as personal reproduction plus the sum of all effects on reproduction of others, each multiplied by their coefficient of relatedness to self. This is the only “natural” equation expected to be represented in the human brain. Third, functional imaging studies show that kinship-related cognition activates frontal-parietal regions that are also activated in STEM-related tasks. In turn, the decision-making that integrates kinship levels with costs and benefits from alternative behaviors has recently been shown to recruit the lateral septum, a hub region that combines internal (from the prefrontal cortex, amygdala, and other regions) and external information relevant to social behavior, using a dedicated subsystem of neurons specific to kinship. Conclusions: Taken together, these lines of evidence suggest that kinship systems and kin-associated behaviors may represent exaptations for the origin of human STEM.

The Phylogenetic Roots of Human Kinship Systems

Nonhuman primates don’t have formal kinship systems, but genetic relatedness shapes patterns of residence, behavior, mating preferences, and cognition in the primate order. The goal of this article is to provide insight about the ancestral foundations on which the first human kinship systems were built. In order for evolution to favor nepotistic biases in behavior, individuals need to have opportunities to interact with their relatives and to be able to identify them. Both these requirements impose constraints on the evolution of kinship bonds in primate species. For nonhuman primates and many other mammals, maternal care generates close ties between mothers and offspring and among littermates. For species in which mother–offspring bonds extend beyond weaning, associations with the mother also generate familiarity among siblings of different ages. For species with female philopatry, mother–offspring ties provide the foundation for lifelong relationships between mothers and daughters, and dense matrilineal kin networks. However, several factors constrain the development of kinship bonds in nonhuman primates. First, dispersal strategies, which are designed to reduce inbreeding, bias kinship networks in favor of the philopatric sex. Second, hostile relationships between groups mean that kin ties are usually severed when individuals move from one group to another. Third, in species with polygynandrous mating systems, uncertainty about paternity and restricted periods of male reproductive monopoly limit the scope for development of ties among fathers and offspring, paternal siblings, or extended paternal kin networks. In this article, I explore the impact of these factors on the evolution of ancestral human kinship systems.

Towards an Evolutionary Account of Human Kinship Systems

Kinship plays a foundational role in organizing human social behavior on both local and more global scales. Hence, any adequate account of the evolution of human sociality must include an account of the evolution of human kinship. This article aims to make progress on the latter task by providing a few key pieces of an evolutionary model of kinship systems. The article is especially focused on the connection between primate social cognition and the origins of kinship systems. I argue that early conceptions of kinship in our line were very likely scaffolded by preexisting forms of primate social cognition. It was only later, as linguistic resources increased in our line, and as human social life grew more complex, that these conceptions came to resemble kin categories as we now know them. I conclude by situating “kin cognition” within a broader cognitive science framework for studying capacities that reflect both innate knowledge and human cultural learning.

A worldwide view of matriliny: using cross-cultural analyses to shed light on human kinship systems.

Although matriliny and matrilocality are relatively rare in contemporary human populations, these female-based descent and residence systems are present in different cultural contexts and across the globe. Previous research has generated numerous hypotheses about which cultural traits are associated with the stability or loss of matrilineal descent. In addition, several studies have examined matrilineal descent with phylogenetic analyses; however, the use of language phylogenies has restricted these analyses to comparisons within a single language family, often confined to a single continent. Cross-cultural comparisons are particularly informative when they account for the relationships between widely distributed populations, as opposed to treating each population as an independent sample or focusing on a single region. Here, we study the evolution of descent systems on a worldwide scale. First, we test for significant associations between matriliny and numerous cultural traits that have been theoretically associated with its stability or loss, such as subsistence strategy, animal domestication, mating system, residence pattern, wealth transfer and property succession. In addition, by combining genetic and linguistic information to build a global supertree that includes 16 matrilineal populations, we also perform phylogenetically controlled analyses to assess the patterns of correlated evolution between descent and other traits: for example, does a change in subsistence strategy generally predict a shift in the rules of descent, or do these transitions happen independently? These analyses enable a worldwide perspective on the pattern and process of the evolution of matriliny and matrilocality. This article is part of the theme issue 'The evolution of female-biased kinship in humans and other mammals'.

Intergenerational and Sibling Conflict Under Patrilocality

Here we argue that models developed to examine cooperation and conflict in communal breeders, using a "tug-of-war" model of reproductive skew generated by incomplete control, are an appropriate way to model human kinship systems. We apply such models to understand the patterns of effort put into competition between father and son and between brothers in conflict over family resources in a patrilineal kinship system. Co-resident kin do not necessarily emerge with equal shares of the cake in terms of reproductive output. The models show that, depending on the efficiency with which they can gain more control of the resource, on the marriage system, and on the relatedness of the partners in conflict, individuals can do better to help their relatives breed rather than fight each other for the resources needed to reproduce. The models show that when a son's father is still breeding with his mother, sons should not compete for any share of reproduction. However, under polygyny, increased effort is spent on father/son and brother/brother conflict. Fathers will win the majority of reproduction if dominant to sons (in contrast to the finding that daughters-in-law win in conflict over mothers-in-law in patrilocal kinship systems, which has been suggested as explaining the evolution of menopause). Hence who wins in the sharing of reproduction depends not just on which sex disperses but also on the relative competitive ability of all individuals to exploit family resources. Anthropologists have long argued that cultural norms can reduce conflict. These formal evolutionary models help us to quantify the effects of reproductive conflict in families, throwing light on the evolutionary basis not just of patterns of reproductive scheduling, but also human kinship and marriage systems.

The Foundation of Kinship

Men's hunting has dominated the discourse on energy capture and flow in the past decade or so. We turn to women's roles as critical to household formation, pair-bonding, and intergenerational bonds. Their pivotal contributions in food processing and distribution likely promoted kinship, both genetic and affinal, and appear to be the foundation from which households evolved. With conscious recognition of household social units, variable cultural constructions of human kinship systems that were sensitive to environmental and technological conditions could emerge. Kinship dramatically altered the organization of resource access for our species, creating what we term "kinship ecologies." We present simple mathematical models to show how hunting leads to dependence on women's contributions, bonds men to women, and bonds generations together. Kinship, as it organized transfers of food and labor energy centered on women, also became integrated with the biological evolution of human reproduction and life history.

The algebraic logic of kinship terminology structures

AbstractJones' proposed application of Optimality Theory assumes the primary kinship data are genealogical definitions of kin terms. This, however, ignores the fact that these definitions can be predicted from the computational, algebralike structural logic of kinship terminologies, as has been discussed and demonstrated in numerous publications. The richness of human kinship systems derives from the cultural knowledge embedded in kinship terminologies as symbolic computation systems, not the post hoc constraints devised by Jones.

Early human kinship: from sex to social reproduction

List of Tables. List of Figures. List of Illustrations. Preface. Acknowledgements. Notes on Contributors. INTRODUCTION AND BACKGROUND. Why 'Kinship'? New Questions on an Old Topic ( Wendy James ). A Brief Overview of Human Evolution ( John A. J. Gowlett and Robin Dunbar ). PART I Where and When: The Archaeological Evidence for Early Social Life in Africa. 1 Kinship and Material Culture: Archaeological Implications of the Human Global Diaspora ( Clive Gamble ). 2 Deep Roots of Kin: Developing the Evolutionary Perspective from Prehistory ( John A. J. Gowlett ). PART II Women, Children, Men - and the Puzzles of Comparative Social Structure. 3 Early Human Kinship Was Matrilineal ( Chris Knight ). 4 Alternating Birth Classes: A Note from Eastern Africa ( Wendy James ). 5 Tetradic Theory and the Origin of Human Kinship Systems ( Nicholas J. Allen ). 6 What Can Ethnography Tell Us about Human Social Evolution? ( Robert Layton ). PART III Other Primates and the Biological Approach. 7 Kinship in Biological Perspective ( Robin Dunbar ). 8 The Importance of Kinship in Monkey Society ( Amanda H. Korstjens ). 9 Meaning and Relevance of Kinship in Great Apes ( Julia Lehmann ). 10 Grandmothering and Female Coalitions: A Basis for Matrilineal Priority? ( Kit Opie and Camilla Power ). PART IV Reconstructions: Evidence from Cultural Practice and Language. 11 A Phylogenetic Approach to the History of Cultural Practices ( Laura Fortunato ). 12 Reconstructing Ancient Kinship in Africa ( Christopher Ehret ). 13 The Co-evolution of Language and Kinship ( Alan Barnard ). EPILOGUE. Reaching across the Gaps ( Hilary Callan ). Appendices to Chapter 12. Bibliography. Index.

Structure and Dynamics Vol.1 No.2: Editorial Commentary

Structure and Dynamics Vol.1 No.2: Editorial Commentary

Group Nepotism and Human Kinship

The human aptitude for collective action may have implications for how the theory of kin selection applies to human kinship. Several models show that if two or more individuals act collectively in assisting their mutual kin, their effective coefficient of relatedness can be greater than if each acts individually. Thus human beings may have psychological adaptations not only for individual nepotism but also for group nepotism—adaptations leading them to construct solidary groups enforcing an ethic of unidirectional altruism toward kin. Human kinship systems have a number of features that seem especially consistent with group nepotism: (1) Human kin groups come in many sizes, ranging from families to clans, lineages, and tribes of thousands of people. (2) Human kinship commonly features an “axiom of amity,” a presumption that kin are entitled to aid simply by virtue of being kin. But this kin altruism is often socially imposed, motivated less by affection between donors and recipients than by social pressure. (3) Relatedness as defined by human kinship systems often differs systematically from biological relatedness and varies with social structure—especially with the solidarity of the kin group. The theory of group nepotism may have implications for a number of research areas in the social sciences. I conclude by focusing on two: demand sharing of food among subsistence hunters and the psychology of ethnocentrism.

Why Polyandry Fails: Sources of Instability in Polyandrous Marriages

Polyandry has long been viewed as an anomalous form of marriage that raises fundamental questions about variability in human kinship systems. This paper integrates and evaluates a set of hypotheses derived from sociocultural anthropological and evolutionary biological theories of polyandry against data collected on the Nyinba, a well‐studied ethnically Tibetan population living in northwestern Nepal. In this population, polyandry is fraternal; it is the normative form of marriage and highly valued culturally. Nonetheless, certain polyandrous marriages fail–‐men occasionally leave their natal households and abandon their joint marriages. In exploring the reasons for these marital breakdowns and the characteristics of men who instigate them, this paper offers a new perspective on the presumed contradictions of polyandry and a more fruitful approach to understanding how polyandrous practice comes to be perpetuated from one generation to the next. It also contributes to discussions about how sociocultural and...

Adoption and Fosterage in Human Societies: Adaptations or Enigmas?

The significance of the role of biological kinship in human social interactions lies at the heart of the contemporary debate over the extent to which natural selection has shaped patterns of human behavior and influenced the structure of human social organization. Some cultural anthropologists contend that there is no relationship between biological relatedness and human kinship systems, and therefore expect to find no systematic association between genetic kinship and patterns of social behavior (e.g., Sahlins 1976; Schneider 1968). At the same time, other anthropologists who have been influenced by contemporary theoretical developments in evolutionary biology, expect kinship' to have a profound impact upon the pattern of human social interactions (e.g., Irons 1979b; Durham 1979). This view derives from the theories of kin selection (Hamilton 1964) and reciprocal altruism (Trivers 1971; Axelrod and Hamilton 1981), which predict that altruistic behaviors, defined in this context as acts that increase the genetic fitness of the recipients at some cost to the donors, will be limited to close kin or reciprocating partners.2 In his influential critique of human sociobiology, Sahlins (1976) cites adoption as compelling evidence that biological kinship plays a relatively unimportant role in the patterning of human social relationships. In Oceania, the North American Arctic, and West Africa a substantial fraction of children grow up outside their natal households (Carroll 1970; Brady 1976; Guemple 1979; Goody 1982). In their adoptive or foster3 households they are nurtured, fed, clothed, housed, socialized, and educated. Adoption, which seems to involve unreciprocated altruism on behalf of genetically unrelated children, apparently violates the predictions of contemporary evolutionary theory (Sahlins 1976). However, the existence of institutions like adoption and fosterage does not necessarily negate the importance of biological kinship relationships (Alexander 1979; Silk 1980). In Oceania, for example, adoption occurs primarily among close kin, natural parents retain an active interest in their children's welfare after adoption, and competition occurs among natal and adoptive siblings over the dis-

Incest and exogamy: A sociobiological reconsideration

Incest and exogamy, though often confused in the social science literature, are two distinct phenomena. Incest avoidance, despite the fact that it is often expressed in humans through incest taboos, has an ancient phylogeny which antedates the development of human culture. Exogamy, on the other hand, is a cultural invention which appeared a few thousand years ago, together with unilineal descent and the domestication of plants and animals. It does not necessarily foster outbreeding because it is often combined with a rule of cross-cousin marriage. Anthropological alliance theory and sociobiological kin selection theory are complementary rather than conflicting analyses of human kinship systems. Humans, like other social animals maintain an optimum balance between inbreeding and outbreeding. For many horti-cultural societies, that balance seems to be produced by rules of marriage encouraging kin to mate if r≤ 1 8 , but forbidding marriage when r≥ 1 4 . Through unilineal descent, clan exogamy, and preferential cross-cousin marriage, many horticultural societies maximize the benefits of both kin selection and reciprocity by marrying cousins ( r≤ 1 8 ) and establishing matrimonial alliances between exogamous clans, while reducing the genetic load of inbreeding through incest taboos against close kin ( r≥ 1 4 ). In effect, the kinsmen “lost” through the principle of unilineal descent are regained as spouses and in-laws.