Various human groups, from food foragers to inner-city urban Americans, have used widespread sharing of resources through kin networks as a means of buffering themselves against fluctuations in resource availability in their environments. This paper addresses the effects of progressive incorporation into a wage-labor economy on the benefits of traditional kin networks for two social classes in urban South India. Predictions regarding the effects of kin network wealth, education, and size on child and spouse characteristics and methods of financing marriages (...) are tested using various regression techniques. Despite the rapid growth of participation in a wage-labor economy, it is found that kin network characteristics still have an important impact on investment behavior among families in Bangalore in both social classes. Network wealth is found to have a positive effect on child and spouse characteristics, and large networks are found to act as significant drains on family resources. However, the results for education are broadly consistent with an interpretation of increasing family autonomy as parents’ education has a far stronger influence on child and spouse characteristics across categories than network education does. Finally, professional-class parents are found to prefer financing marriages using formal mechanisms such as savings and bank loans while working-class parents preferentially finance marriages using credit from relatives and friends. (shrink)

Supporting Hamilton’s inclusive fitness theory, archival analyses of inheritance patterns in wills have revealed that people invest more of their estates in kin of closer genetic relatedness. Recent classroom experiments have shown that this genetic relatedness effect is stronger for relatives of direct lineage (children, grandchildren) than for relatives of collateral lineage (siblings, nieces, nephews). In the present research, multilevel modeling of more than 1,000 British Columbian wills revealed a positive effect of genetic relatedness on proportions of estates allocated to (...) relatives. This effect was qualified by an interaction with lineage, such that it was stronger for direct than for collateral relatives. Exploratory analyses of the moderating role of benefactors’ sex and estate values showed the genetic relatedness effect was stronger among female and wealthier benefactors. The importance of these moderators to understanding kin investment in modern humans is discussed. (shrink)

Paternity certainty and matrilineal family ties have been used to explain the asymmetric caregiving of grandparents and aunts and uncles. The proximate mechanisms underlying biased kin investment, however, remain unclear. A central question of the study presented here was whether the parent-kin relationship is an important link in the caregiving. In a two-generational questionnaire study, we asked subjects to estimate the intensity of their relationships to parents, grandparents, aunts, and uncles (emotional closeness, investment received in childhood). In addition, (...) the subjects’ parents rated their emotional closeness to their parents and siblings. We found that the parent-kin relationship was closely linked to the relatives’ child care and could partly explain asymmetric caregiving. Maternal aunts played a special role as caregivers. Especially the mother’s younger or last-born sister cared intensively for nieces and nephews, regardless of her closeness to the subjects’ mother. (shrink)

Gaulin, McBurney, and Brakeman-Wartell (1997) found that college students reported both matrilateral and sex biases in the investment of aunts and uncles (aunts invested more than uncles). They interpreted the matrilateral bias as a consequence of paternity uncertainty. We replicated that study with Orthodox Jewish college students, selected because they come from a population we presume to have higher paternity certainty than the general population. The Orthodox sample also showed matrilateral and sex biases. Comparing the two data sets, the (...) Orthodox sample reported more investment, and slightly less matrilateral and sex biases, but the differences were not statistically significant. We did find an interaction between sex of relative and group membership, resulting from greater investment by Orthodox uncles. We interpret the results as reflecting the operation of a facultative investment mechanism whose upper limit is tuned to the maximum levels of paternity certainty found in ancestral environments. Lack of a difference in matrilateral bias between groups may result from levels of paternity certainty near to, or above, that maximum in both groups. (shrink)

This study examines child survival and growth in a patrilineal Ethiopian community as a function of father absence and sex. In line with evolutionary predictions for sex-biased parental investment, the absence of a father and associated constraints on household resources is more detrimental for sons’ than daughters’ survival in infancy. Father absence doubles a son’s risk of dying in infancy but has a positive influence on the well-being of female members of the household, improving daughter survival, growth, and maternal (...) nutritional status. Lack of paternal investment may be compensated for by other matrilateral kin through increased reciprocity between mother, daughter, and sister. (shrink)

In a study of the kin investment of aunts and uncles we show that the laterality effect expected as a result of paternity uncertainty is statistically reliable but somewhat smaller than the sex effect. Matrilateral aunts invest significantly more than patrilateral aunts, and the same is true for uncles. Regardless of laterality, however, aunts invest significantly more than uncles. Multivariate controls show that the matrilateral bias is fully independent of any age or distance confounds that might result from sex (...) differences in age at marriage or dispersal. We discuss our results in relation to recent findings on the kin investment of grandparents (Euler and Weitzel 1996). In addition, we propose a simple method for estimating the level of paternity uncertainty from kin investment data; application of this method to our data on aunts and uncles suggests that between 13% and 20% of children are not the offspring of their putative father. Our parallel analyses of Euler and Weitzel’s (1996) data on grandparental investment suggest a similar estimate, that paternity uncertainty lies between 9% and 17%. (shrink)

What motivates grandparents to their altruism? We review answers from evolutionary theory, sociology, and economics. Sometimes in direct conflict with each other, these accounts of grandparental investment exist side-by-side, with little or no theoretical integration. They all account for some of the data, and none account for all of it. We call for a more comprehensive theoretical framework of grandparental investment that addresses its proximate and ultimate causes, and its variability due to lineage, values, norms, institutions (e.g., inheritance (...) laws), and social welfare regimes. This framework needs to take into account that the demographic shift to low fecundity and mortality in economically developed countries has profoundly altered basic parameters of grandparental investment. We then turn to the possible impact of grandparental acts of altruism, and examine whether benefits of grandparental care in industrialized societies may manifest in terms of less tangible dimensions, such as the grandchildren's cognitive and verbal ability, mental health, and well-being. Although grandparents in industrialized societies continue to invest substantial amounts of time and money in their grandchildren, we find a paucity of studies investigating the influence that this investment has on grandchildren in low-risk family contexts. Under circumstances of duress there is converging evidence that grandparents can provide support that helps to safeguard their children and grandchildren against adverse risks. We conclude by discussing the role that grandparents could play in what has been referred to as Europe's demographic suicide. (shrink)

Social support networks play a key role in human livelihood security, especially in vulnerable communities. Here we explore how evolutionary ideas of kin selection and intrahousehold resource competition can explain individual variation in daily support network size and composition in a south-central Ethiopian agricultural community. We consider both domestic and agricultural help across two generations with different wealth-transfer norms that yield different contexts for sibling competition. For farmers who inherited land rights from family, firstborns were more likely to report daily (...) support from parents and to have larger nonparental kin networks. Compared with other farmers, firstborns were also more likely to reciprocate their parents’ support, and to help nonparental kin without reciprocity. For farmers who received land rights from the government, middle-born farmers reported more nonparental kin in their support networks compared with other farmers; nonreciprocal interactions were particularly common in both directions. This suggests a diversification of adult support networks to nonparental kin, possibly in response to a long-term parental investment disadvantage of being middle-born sons. In all instances, regardless of inheritance, lastborn farmers were the most disadvantaged in terms of kin support. Overall, we found that nonreciprocal interactions among farmers followed kin selection predictions. Direct reciprocity explained a substantial part of the support received from kin, suggesting the importance of the combined effects of kin selection and reciprocity for investment from kin. (shrink)

Several studies have suggested a matrilateral bias in allomaternal (non-maternal) infant and child caregiving. The bias has been associated with the allomother’s certainty of genetic relatedness, where allomothers with high certainty of genetic relatedness will invest more in children because of potential fitness benefits. Using quantitative behavioral observations collected on Ngandu 8- to 12-month-old infants from the Central African Republic, I examine who is caring for infants and test whether certainty of genetic relatedness may influence investment by allomothers. Results (...) indicate a matrilateral bias in caregiving by extended kin members, but this does not affect the total level of care infants receive when fathers and siblings are included in the analysis. These results replicate a previous study done among an adjacent foraging population and emphasize the importance of examining children’s complete social environments when addressing caregiving and child development. (shrink)

The effects of grandparental investment in relatives are apparent in human groups, suggesting that a postreproductive period in humans is selective. Although investment of relatives in kin produces obvious benefits for kin groups, selection for a postreproductive period in humans is not supported by evidence from chimpanzees. Instead, grandparental investment is likely a recent phenomenon of longevity, rather than an evolved feature.

The role of olfaction in kin recognition and parental investment is documented in many mammalian/vertebrate species. Research on humans, however, has only focused on whether parents are able to recognize their children by smell, not whether humans use these cues for investment decisions. Here we show that fathers exhibit more affection and attachment and fewer ignoring behaviors toward children whose smell they can identify than toward those whose smell they cannot recognize. Thus, olfaction might serve as a means (...) for males to determine their genetic relatedness to purported offspring. We also demonstrate that mothers’ olfactory recognition and hedonistic ratings are linked with the use of physical punishment. Mothers report using more punishment with children whose odor they cannot recognize and less with children whose odor they rated as more pleasant. These results provide the first preliminary evidence in humans that olfactory cues may guide parents in the allocation of care. (shrink)

In the analysis of intergenerational transfer, several improvements can be made. First, following kin selection theory, grandparents have kin other than grandchildren in which to invest and therefore any investigation into grandparents should take this perspective. Secondly, how transfers actually enhance the survivorship of younger relatives such as grandchildren must be better measured, especially in the ethnographic literature. Finally, the problem of indirect investments or targeting must be considered.

Birth order has been examined over a wide variety of dimensions in the context of modern populations. A consistent message has been that it is better to be born first. The analysis of birth order in this paper is different in several ways from other investigations into birth order effects. First, we examine the effect of birth order in an egalitarian, small-scale, kin-based society, which has not been done before. Second, we use a different outcome measure, fertility, rather than outcome (...) measures of social, psychological, or economic success. We find, third, that being born late in an egalitarian, technologically simple society rather than being born early has a positive outcome on fertility, and fourth, that number of older siblings and sibling set size are even stronger predictors of fertility, especially for males. (shrink)

Previous research indicates that birth order is a strong predictor of familial sentiments, with middleborns less family-oriented than first- or last-borns. In this research, effects of sex and birth order on the actual frequency of contact with maternal and paternal kin were examined in two studies. In Study 1, one hundred and forty undergraduates completed a questionnaire relating to the amount of time they spent in contact with specific relatives, while in Study 2, one hundred and twelve undergraduates completed the (...) same questionnaire with the addition of two questions relating to the subjects’ parents’ birth orders. Subjects were more likely to have frequent contact with maternal, as opposed to paternal, kin and women experienced more frequent contact than men with relatives in general. The birth order of subjects did not appear to have a significant influence on contact but the birth order of the subjects’ parents did, with the offspring of middleborn mothers having relatively little contact with maternal grandparents and the offspring of middleborn fathers having relatively little contact with paternal grandparents. These sex and birth order differences are discussed in relation to possible differences in how women and men use kinship ties and in terms of how birth order may influence parental solicitude. (shrink)

Putting migrant remittances into house construction and rebuilding is generally seen as either conspicuous consumption or productive investment, but in both cases the perspective is economistic. This article argues that only when the cultural dimension of economic action is understood will it be possible to comprehend migrant spending on houses. Specifically, this article seeks to understand why, in the case of the rural Tagalog village in this study, located in upland Batangas Province in the Philippines, overseas labour migrants build (...) houses that they do not even live in, but are given to parents or simply left unoccupied. The explanation is framed in relation to the meanings of houses in a culture of bilateral kinship, which the Philippines shares with most parts of Southeast Asia, but inflected by distinct colonial influences. The article demonstrates the ways in which houses as memorials serve as idioms of ties of relatedness within kin groups and the broader community, ties that are being transformed by global migration and experienced differently yet maintained, renegotiated yet sustained transnationally. (shrink)

In this paper I examine the intracultural variability of parental and alloparental caregiving among the Aka foragers of the Central African Republic. It has been suggested that maternal kin offer higher frequencies of allocare than paternal kin and that maternal investment in infants will decrease when alloparental assistance is provided. Behavioral observations were conducted on 15 eight- to twelve-monthold infants. The practice of brideservice and the flexibility of Aka residence patterns offered a means to test the effect of maternal (...) residence on parental and alloparental investment. There was significant variation in the frequency of investment and who supplied care to infants depending on whether mothers resided with their kin or their husbands’ kin. However, in spite of the variation in allocare, when all categories of caregivers were examined collectively, infants received similar overall levels of care. (shrink)

In this paper I examine the intracultural variability of parental and alloparental caregiving among the Aka foragers of the Central African Republic. It has been suggested that maternal kin offer higher frequencies of allocare than paternal kin and that maternal investment in infants will decrease when alloparental assistance is provided. Behavioral observations were conducted on 15 eight- to twelve-monthold infants. The practice of brideservice and the flexibility of Aka residence patterns offered a means to test the effect of maternal (...) residence on parental and alloparental investment. There was significant variation in the frequency of investment and who supplied care to infants depending on whether mothers resided with their kin or their husbands’ kin. However, in spite of the variation in allocare, when all categories of caregivers were examined collectively, infants received similar overall levels of care. (shrink)

This response outlines more reasons why we need the integrative framework of grandparental investments and intergenerational transfers that we advocated in the target article. We discusses obstacles that stand in the way of such a framework and of a better understanding of the effects of grandparenting in the developed world. We highlight new research directions that have emerged from the commentaries, and we end by discussing some of the things in our target article about which we may have been wrong.

Capturing a scientific change in thinking about personality and individual differences that has been building over the past 15 years, this volume stands at an important moment in the development of psychology as a discipline. Rather than viewing individual differences as merely the raw material upon which selection operates, the contributing authors provide theories and empirical evidence which suggest that personality and individual differences are central to evolved psychological mechanisms and behavioral functioning. The book draws theoretical inspiration from life history (...) theory, evolutionary genetics, molecular genetics, developmental psychology, personality psychology, and evolutionary psychology, while utilizing the theories of the "best and the brightest" international scientists working on this cutting edge paradigm shift. In the first of three sections, the authors analyze personality and the adaptive landscape; here, the authors offer a novel conceptual framework for examining "personality assessment adaptations." Because individuals in a social environment have momentous consequences for creating and solving adaptive problems, humans have evolved "difference-detecting mechanisms" designed to make crucial social decisions such as mate selection, friend selection, kin investment, coalition formation, and hierarchy negotiation. In the second section, the authors examine developmental and life-history theoretical perspectives to explore the origins and development of personality over the lifespan. The third section focuses on the relatively new field of evolutionary genetics and explores which of the major evolutionary forces--such as balancing selection, mutation, co-evolutionary arms races, and drift--are responsible for the origins of personality and individual differences. Existing as a seminal work in the newly emerging evolutionary psychology field, this book is a "must-read" for anyone invested in the development of psychology as a field. (shrink)

The kin selection hypothesis posits that male androphilia (male sexual attraction to adult males) evolved because androphilic males invest more in kin, thereby enhancing inclusive fitness. Increased kin-directed altruism has been repeatedly documented among a population of transgendered androphilic males, but never among androphilic males in other cultures who adopt gender identities as men. Thus, the kin selection hypothesis may be viable if male androphilia was expressed in the transgendered form in the ancestral past. Using the Standard Cross-Cultural Sample (SCCS), (...) we examined 46 societies in which male androphilia was expressed in the transgendered form (transgendered societies) and 146 comparison societies (non-transgendered societies). We analyzed SCCS variables pertaining to ancestral sociocultural conditions, access to kin, and societal reactions to homosexuality. Our results show that ancestral sociocultural conditions and bilateral and double descent systems were more common in transgendered than in non-transgendered societies. Across the entire sample, descent systems and residence patterns that would presumably facilitate increased access to kin were associated with the presence of ancestral sociocultural conditions. Among transgendered societies, negative societal attitudes toward homosexuality were unlikely. We conclude that the ancestral human sociocultural environment was likely conducive to the expression of the transgendered form of male androphilia. Descent systems, residence patterns, and societal reactions to homosexuality likely facilitated investments in kin by transgendered males. Given that contemporary transgendered male androphiles appear to exhibit elevated kin-directed altruism, these findings further indicate the viability of the kin selection hypothesis. (shrink)

We conducted a meta-analysis of 17 studies that tested for an association between grandparental survival and grandchild survival in patrilineal populations. Using two different methodologies, we found that the survival of the maternal grandmother and grandfather, but not the paternal grandmother and grandfather, was associated with decreased grandoffspring mortality. These results are consistent with the findings of psychological studies in developed countries (Coall and Hertwig Behavioral and Brain Sciences 33:1-59, 2010). When tested against the predictions of five hypotheses (confidence of (...) paternity; grandmothering, kin proximity, grandparental senescence, and local resource competition), our meta-analysis results are most in line with the local resource competition hypothesis. In patrilineal and predominantly patrilocal societies, the grandparents who are most likely to live with the grandchildren have a less beneficial association than those who do not. We consider the extent to which these results may be influenced by the methodological limitations of the source studies, including the use of retrospective designs and inadequate controls for confounding variables such as wealth. (shrink)

Cooperative child care among humans, where individuals other than the biological mother (allomothers) provide care, may increase a mother’s fertility and the survivorship of her children. Although the potential benefits to the mother are clear, the motivations for allomothers to provide care are less clear. Here, we evaluate the kin selection allomothering hypothesis using observations on Hadza hunter-gatherers collected in ten camps over 17 months. Our results indicate that related allomothers spend the largest percentage of time holding children. The higher (...) the degree of relatedness among kin, the more time they spend holding, supporting the hypothesis of nepotism as the strongest motivation for providing allomaternal care. Unrelated helpers of all ages also provide a substantial amount of investment, which may be motivated by learning to mother, reciprocity, or coercion. (shrink)

Reproductive senescence in human females takes place long before other body functions senesce. This fact presents an evolutionary dilemma since continued reproduction should generally be favored by natural selection. Two commonly proposed hypotheses to account for human menopause are (a) a recent increase in the human lifespan and (b) a switch to investment in close kin rather than direct reproduction. No support is found for the proposition that human lifespans have only recently increased. Data from Ache hunter-gatherers are used (...) to test the kin selection hypothesis. Ache data do not support the proposition that females can gain greater fitness benefits in old age by helping kin rather than continuing to reproduce. Nevertheless, one crucial parameter in the model, when adjusted to the highest value within the measured 95% confidence interval, would lead to the evolution of reproductive senescence at about 53 years of age. Further investigation is necessary to determine whether the kin selection hypothesis of menopause can account for its current maintenance in most populations. (shrink)

Previous studies (Salmon 1999; Salmon and Daly 1998) have found that sex and birth order are strong predictors of familial sentiments. Middleborns tend to be less family-oriented than firstborns or lastborns, while sex differences seem to focus on the utility of kin in certain domains. If this is a reflection of middleborns receiving a lesser degree of support from kin (particularly in terms of parental investment), are middleborns turning to reciprocal alliances outside the family, becoming friendship specialists? Are there (...) comparable birth order differences with respect to mating strategies? In this study, the impact of birth order on attitudes toward family, friends, and mating were examined. Two hundred and forty-five undergraduates completed a questionnaire relating to their attitudes toward friends and family as well as some aspects of mating behavior. Birth order did have a significant impact in several areas. Middleborns expressed more positive views toward friends and less positive opinions of family in general. They were less inclined to help family in need than firstborns or lastborns. Mating strategies also appeared to be influenced by birth order, most notably in the area of infidelity, with middleborns being the least likely birth order to cheat on a sexual partner. (shrink)

This target article presents an integrated evolutionary model of the development of attachment and human reproductive strategies. It is argued that sex differences in attachment emerge in middle childhood, have adaptive significance in both children and adults, and are part of sex-specific life history strategies. Early psychosocial stress and insecure attachment act as cues of environmental risk, and tend to switch development towards reproductive strategies favoring current reproduction and higher mating effort. However, due to sex differences in life history trade-offs (...) between mating and parenting, insecure males tend to adopt avoidant strategies, whereas insecure females tend to adopt anxious/ambivalent strategies, which maximize investment from kin and mates. Females are expected to shift to avoidant patterns when environmental risk is more severe. Avoidant and ambivalent attachment patterns also have different adaptive values for boys and girls, in the context of same-sex competition in the peer group: in particular, the competitive and aggressive traits related to avoidant attachment can be favored as a status-seeking strategy for males. Finally, adrenarche is proposed as the endocrine mechanism underlying the reorganization of attachment in middle childhood, and the implications for the relationship between attachment and sexual development are explored. Sex differences in the development of attachment can be fruitfully integrated within the broader framework of adaptive plasticity in life history strategies, thus contributing to a coherent evolutionary theory of human development. (shrink)

In most cultures, extramarital sex is highly restricted for women. In most of those cultures, men transfer wealth to their own sons. In some cultures extramarital sex is not highly restricted for women, and in most of those cultures, men transfer wealth to their sisters' sons. Inheritance to sisters' sons ensures a man's biological relatedness to his heirs, and matrilineal inheritance has been posited as a male accommodation to cuckoldry—a paternity strategy—at least since the 15th century. However, longitudinal analysis of (...) the cumulative effect of female extramarital sex indicates that matrilineal inheritance is most advantageous for women and would be more accurately considered a grandmaternity strategy. That is, if the probability that men's putative children are their biological children is less than 1, the probabilistic degree of relatedness between a female and her matrilineal heirs is higher than her corresponding relatedness to her patrilineal heirs. The same holds true for men only if ρ is very low. The upshot is that for moderate levels of female extramarital sex, matrilineal inheritance, relative to patrilineal inheritance, is highly advantageous for women and disadvantageous for men. Consideration of female variance in reproductive success beyond the first generation, and of a man's network of obligation to the inclusive fitness of his relatives, suggests that although the establishment of matrilineal inheritance may require extremely high levels of female extramarital sex, once established, it is likely to be maintained at levels of ρ that reasonably characterize many societies in the ethnographic record. New analysis of previously published data shows a strong association between matrilineal inheritance and moderate to low probability of paternity, and an even stronger relationship between patrilineal inheritance and high probability of paternity. (shrink)

Breastfeeding is one important form of maternal investment that is influenced by support from kin and non-kin. This paper investigates who provides support for breastfeeding mothers and their children, what type of support they provide, and how support impacts breastfeeding duration. The data were derived from a survey of 594 American mothers and were analyzed using quantitative methods, including Cox regression. Analyses indicate that mothers receive significant support, particularly from spouses and maternal grandmothers. More frequent breastfeeding discussions with La (...) Leche League and maternal grandfathers were associated with longer duration, whereas discussions with physicians were associated with shorter breastfeeding duration. Results indicate that consulting others specifically about breastfeeding may influence breastfeeding decisions. The results are consistent with the idea that social support may influence breastfeeding duration and that some types of support are more influential than others. Furthermore, support persons should be educated about breastfeeding to prevent early weaning. (shrink)

It is almost 30 years since the sociobiology controversy burst into full bloom. The modern theory of the evolution of animal behavior was born in the mid 1960’s with Bill Hamilton’s seminal papers on inclusive fitness and George William’s book Adaptation and Natural Selection. The following decade saw an avalanche of important ideas on the evolution of sex ratio, animal conflicts, parental investment, and reciprocity, setting off a revolution our understanding of animal societies, a revolution that is still going (...) on today. By the mid-1970’s, Richard Alexander, E. O. Wilson, Napoleon Chagnon, Bill Irons, and Don Symons among others began applying these ideas to understand human behavior. Humans are evolved creatures, and quite plausibly the same evolutionary forces that shaped the behavior of other animals also molded our behavior. Moreover, the new theory of animal behavior—especially, kin selection, parental investment, and optimal foraging theory—seemed fit the data on human societies fairly well. (shrink)

This target article presents an integrated evolutionary model of the development of attachment and human reproductive strategies. It is argued that sex differences in attachment emerge in middle childhood, have adaptive significance in both children and adults, and are part of sex-specific life history strategies. Early psychosocial stress and insecure attachment act as cues of environmental risk, and tend to switch development towards reproductive strategies favoring current reproduction and higher mating effort. However, due to sex differences in life history trade-offs (...) between mating and parenting, insecure males tend to adopt avoidant strategies, whereas insecure females tend to adopt anxious/ambivalent strategies, which maximize investment from kin and mates. Females are expected to shift to avoidant patterns when environmental risk is more severe. Avoidant and ambivalent attachment patterns also have different adaptive values for boys and girls, in the context of same-sex competition in the peer group: in particular, the competitive and aggressive traits related to avoidant attachment can be favored as a status-seeking strategy for males. Finally, adrenarche is proposed as the endocrine mechanism underlying the reorganization of attachment in middle childhood, and the implications for the relationship between attachment and sexual development are explored. Sex differences in the development of attachment can be fruitfully integrated within the broader framework of adaptive plasticity in life history strategies, thus contributing to a coherent evolutionary theory of human development. (shrink)

The 1000-year-old novel The Tale of Genji, written by Murasaki Shikibu around 1002 CE, shows the operation of general principles of sociobiology. Isolated from western influences and cloaked in Japanese traditions, the common traits associated with reproductive processes are clearly evident. The novel depicts the differential investment of males and females in offspring, male competitive behaviors, and concerns for paternity, kin selection, reciprocal social exchange, species-typical emotional expression, female mate choice, positive assortative mating, and acknowledgment of hereditary transmission of (...) physical and psychological traits. The nature of human behavior in Genji’s time seems little different than now and has all the attributes of species-specific and universal traits. Indeed, it can be argued that the fundamental characteristics of Homo sapiens have never changed, being influenced only in form by culture. The qualitative and quantitative evaluation of ancient texts is a strong methodology for understanding the invariant nature of human behavior. (shrink)

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. (shrink)

MacDonald develops an evolutionary perspective on Judaism. Judaism is conceptualized as a group evolutionary strategy characterized by a high degree of endogamy and resistance to genetic and cultural assimilation. Data are provided to support the author's theory that Judaism is characterized by a high level of within-group altruism and competition with outgroups. Finally, MacDonald argues that Judaism has been characterized by eugenic practices aimed at high intelligence and high investment parenting. After outlining a theory of evolutionary group strategies, MacDonald (...) discusses the evidence from modern studies showing population genetic differences between Jews and Gentiles. He then shows that Jewish religious writing points to a pronounced tendency toward idealizing endogamy and condemning exogamy, and he points to the ways religious ideology and practice have facilitated the genetic and cultural separation of Jews and Gentiles. He then reviews evidence for resource and reproductive competition and the importance of kin-based cooperation and altruism as well as assortative mating for intelligence and resource aquisition ability among Jews. This study is a highly original attempt to develop an evolutionary understanding of one of the world's great religions. As such, it will be of concern to scholars and researchers in the fields of sociobiology and religion as well as the general reading public. (shrink)

Based on historical data pertaining to the Krummhörn population (eighteenth and nineteenth centuries, Germany), we compared reproductive histories of mothers according to whether the maternal grandmother (MGM) or the paternal grandmother (PGM) or neither of them was resident in the parents’ parish at the time of the mother’s first birth. In contrast to effects of PGMs, we discovered conditional differences in the MGM’s effects between landless people and wealthier, commercial farmers. Our data indicate that the presence of the MGM only (...) lowers the woman’s age at marriage (AAM) and her age at the birth of her first child (AFB) in the case of landless families. However, among commercial farmers, who can generally be characterized by a lower AAM and AFB, we found opposite tendencies for the MGM’s effect leading to a relatively small delay in AAM and AFB. Moreover, we also analyzed differences in the completed fertility (i.e., children ever born: CEB). Results indicate that landless families in general do have fewer CEB compared with commercial farmers except for those families in which the MGM has been present. Emphasizing that the adaptiveness of investment decisions should depend on the interaction of genetic, lineage-specific (intrinsic) and ecologically imposed (extrinsic) constraints, we conclude that kin strategies consequently address different fitness components under different conditions. (shrink)

Grandparental presence is known to correlate with the number of grandchildren born, and this effect may vary according to grandparental sex and lineage. However, existing studies of grandparental effects on fertility mostly concern traditional subsistence societies, while evidence from contemporary developed societies is both scarce and mixed. Here, we explore how grandparents affect the transition to second and subsequent children in the contemporary United Kingdom. The longitudinal Millennium Cohort Study (n = 10,295 families) was used to study the association between (...) grandparental investment and parents’ probability of having a new child within 4.5 years. Results show that contact with paternal grandparents is associated with higher probability of parents having a second child. In contrast, contact with maternal grandparents is associated with lower probability of having a third or subsequent child. Kin may have opposite effects on fertility even in contemporary societies, which may explain the lack of consistent effects of grandparental investment on fertility in previous studies. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy and Literature 26.2 (2002) 296-311 [Access article in PDF] Byron As Cad Ian Jobling I AS ONE OF THE MOST IMPORTANT and intriguing poets of the romantic period, Byron has been the subject of much recent critical commentary. However, no matter how excellent some of this scholarship is, the reader who is familiar with evolutionary psychology, the science that has tried to explain the biological underpinnings of human (...) nature, inevitably comes away from it with a feeling of dissatisfaction. In spite of the obvious relevance of biological theories of human behavior to the most basic issues of literary interpretation, only a handful of literary critics, and no Byron critics, have attempted to use these theories to understand the creation and reception of literary texts. All literary criticism relies on assumptions about human nature; because most critics are unfamiliar with evolutionary psychology, these assumptions are almost never clarified and justified. By familiarizing themselves with evolutionary psychology, literary critics can replace their vague, commonsensical, and often empirically unsupported assumptions about human nature with more precise and empirically valid theories.Much recent research on the evolution of sexuality has focused on "cad" and "dad" mating strategies in men. Cads seek to maximize their reproductive success by maximizing the number of their sexual partners and by avoiding parental investment; dads are committed to long-term, monogamous relationships with women and make substantial parental investment in their children. The personality traits of cads—aggressiveness, rebelliousness, criminality, and sexual promiscuity—bear a close resemblance both to Byron's own personality traits and to those of the Byronic hero. Understanding the cad mating strategy [End Page 296] enables us to better understand Byron's personality as well as the conflicts between his personality and the culture of his time that shaped his literary production and reception. II Evolutionary psychology uses the principles of evolutionary biology as a guide to the study of human cognition and behavior. The types of psychological traits that will succeed evolutionarily are those that maximize an organism's ability to transmit its genes to the next generation, or what evolutionary psychologists call its "fitness," by successfully reproducing and by helping kin who share its genes to reproduce. Our psychological design did not evolve in the environment that we now inhabit but on the African savannah of the Pleistocene era; therefore, evolved human psychology is best understood not in relation to the lifestyle of the citizens of modern nation-states, but to that of hunter-gatherers. 1Recent research on human sexuality has suggested that humans have evolved to pursue two different types of mating strategies: short-term and long-term. On the one hand, there is a great deal of evidence to suggest that, unlike most mammals, humans are designed for long-term sexual relationships with substantial male parental investment in children. Human infants require a great deal of parental care, and children reared in father-absent households suffer much higher mortality rates than those who are reared in father-present households, especially in preindustrial societies. 2 The sexual psychology of women also indicates that human sexuality has been shaped by long-term sexual relationships. A number of studies both in the United States and across cultures have shown that women regularly report being attracted to men who are socially respected, financially well-off, ambitious, industrious, dependable, emotionally stable, and romantic, 3 all qualities that indicate the ability and willingness to sustain long-term, parentally investing relationships with women.However, there are also aspects of both men's and women's sexuality that show that we did not evolve exclusively to pursue long-term mating. The evidence for the importance of short-term mating in human evolution is most obvious in men, who consistently show a marked desire for sexual variety. For example, in a survey, male college students said that they would, on average, like to have six partners in the coming year, and men fantasize about having sex with multiple partners (Buss, [End Page 297] ED, pp. 76-83). The fitness advantage of short-term sexual relationships to men is obvious: men can have more offspring the... (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Speculative ReproductionBiotechnologies and Ecologies in Thick TimeAstrida NeimanisEveryone loves me, Frida and the Abortion that fetus So Much Larger Than Life. Everyone loves that one. irrigation channelsthese waters as thick as blood (There is another painting I did, I called it “Roots.”) You the golden beets the potato bugs We are eating our young. Signed,—Frida Kahlo, Posthuman Gardener1 [End Page 108]IntroductionBirth has never been a “natural” matter. In the (...) context of proliferating new reproductive biotechnologies, we might be tempted to reconstitute a past when ushering new lives into this world only ever happened “naturally.” Yet reproduction has always been more than a simple question of fertilization, gestation, and delivery, whereby bodies might enact some natural biological destiny.2 Every reproduction is what we might call, after Donna Haraway, a “naturalcultural” one: that is, an inextricable entanglement of “natural” forces, matters, and processes, with “cultural” systems, values, and institutions (Haraway 2004, 2, 212–18) that together constitute a birthing ecology. Every human reproduction is thus not only a birthing of a human body, but also an event within certain conditions of possibility—a reaffirmation of, challenge to, and/or intervening otherwise in the structures, institutions, cultures, and ecologies of human and more-than-human bodies and technologies. On this view, a failure to birth, a decision not to birth, or a direction of one’s reproductive body or matter toward other kinds of births (not necessarily of one’s “own” child) are also “reproductions” within birthing ecologies. This is not at all to say that the reproductions we facilitate are always deliberate political choices or purposeful acts of compliance/subversion, even if in some cases they might be. Rather, it is to underline that all births are a co-configuration of naturalcultural bodies in context. What is birthed is also the affirmation of certain kinds of births, certain kinds of life, and certain value systems according to which life and reproduction are understood. Within this frame, we might also understand birth as the creation or reproduction of certain social and cultural imaginaries within which our values are oriented. Concomitant with such naturalcultural reproductions, then, might also be a speculation about what other sorts of births and birthing ecologies are possible—ones that might engender values and relations in which the technologies and naturecultures of reproduction can be imagined anew.In this paper, I contrast two very different versions of a reproductive imaginary—both birthed through the matter of our reproductive tissues, and both worth our consideration in the present moment. The first is the birthing of a neoliberal, individualistic reproductive imaginary of commodification and amnesiac bioscientific progress. Using terminology unpacked in more detail below, we might call this an autologous imaginary, where reproduction is disentangled from any obligation to other bodies in a polity of mutual care and concern. This imaginary promotes an erasure of the thick past of bodies and labors that produce reproductive tissues, and is focused primarily on preservation of the self and direct kin. This is what we find in dominant contemporary biobanking trends that divert human reproductive matter (here, [End Page 109] embryos, amniotic fluid, and umbilical cord blood) in the service of speculative “biological venture capital[ism]” (Waldby and Mitchell 2006, 123).In contrast, I consider a different kind of contemporary birthing imaginary, wherein one invests one’s reproductive matter in the service of both human and more-than-human reproductive ecologies. Drawing on two different artworks, I suggest that these creative interventions offer alternative “speculative reproductions.” Like contemporary biobanking regimes, these artworks speculate on what new kinds of bodies the reinvestment of reproductive matter (in this case, amniotic fluid and menstrual blood) might engender. Unlike the neoliberal regimes, however, these artworks confirm rather than repudiate a feminist ethics of corporeal generosity, and in fact, extend this ethics even further, through an imaginary of what I call posthuman gardening. Here, the literal resowing and reseeding of one’s reproductive matter establishes an extended, more-than-human birthing ecology that includes not only human bodies, but ecological bodies of various kinds. In this productive troubling of our commonplace Western and humanist understandings of the spacetimes of birth, we... (shrink)

Humans spend large portions of their time and energy talking to one another, yet it remains unclear whether this activity is primarily selfish or altruistic. Here, it is shown how parent‐of‐origin specific gene expression—or “genomic imprinting”—may provide an answer to this question. First, it is shown why, regarding language, only altruistic or selfish scenarios are expected. Second, it is pointed out that an individual's maternal‐origin and paternal‐origin genes may have different evolutionary interests regarding investment into language, and that this (...) intragenomic conflict may drive genomic imprinting which—as the direction of imprint depends upon whether investment into language is relatively selfish or altruistic—may be used to discriminate between these two possibilities. Third, predictions concerning the impact of various mutations and epimutations at imprinted loci on language pathologies are derived. In doing so, a framework is developed that highlights avenues for using intragenomic conflicts to investigate the evolutionary drivers of language. (shrink)

The seventeenth-century Puritan theologian Jonathan Edwards has become popular again in contemporary theological discussion. Central to Edwards' theology is his concept of beauty. Delattre wrote the standard work on this topic half a century ago. However, Delattre approaches Edwards mainly as a philosopher, and he does not address how Edwards employs the concept of beauty to explain and defend traditional Reformed doctrines. Recent writings by McClymond, Holmes, and others have shown that defending the Reformed tradition is a fundamental concern of (...) Edwards. This work reveals how Edwards, starting with the common notion that beauty means the appropriate proportional relationship, develops a theological aesthetic that contributes to a rational understanding of major doctrines such as the Trinity, Christology, and eschatology. It shows that Edwards is both an innovative speculative theologian and a staunch defender of Reformed orthodoxy. (shrink)

The book is a collection of essays written by Gustavo Esteva over the last 20 years. In this book, Gustavo Esteva, renowned in Mexico as a philosopher on education and on developmentalism, collects four major areas of his writings: on learning, development, autonomy, and interculturality. A memorial to a great thinker, this book stimulates thoughts on developmentalism across the global south.

We study the class of all strongly constructivizable models having \(\omega \) -stable theories in a fixed finite rich signature. It is proved that the Tarski–Lindenbaum algebra of this class considered together with a Gödel numbering of the sentences is a Boolean \(\Sigma ^1_1\) -algebra whose computable ultrafilters form a dense subset in the set of all ultrafilters; moreover, this algebra is universal with respect to the class of all Boolean \(\Sigma ^1_1\) -algebras. This gives a characterization to the Tarski-Lindenbaum (...) algebra of the class of all strongly constructivizable models with \(\omega \) -stable theories. (shrink)

This paper takes Deleuze's idea ‘to green’ as a qualitative predicate which becomes a rhizomatic event where Jesper Hoffmeyer's ‘plant being’ contemplates through waves and rhythms, hence affects and percepts. The article then brings forward an intertwined group of Chinese ideograms which are designed with plant-radicals, making up an ecosystem towards the establishment of a new Chinese ecocriticism under the banner of biosemiotics. Such an effort will, hopefully, widen the scope and dimension of the new field of environmental humanities, with (...) an emphasis on the scenario of affective attuning to the agency of vegetal life. The main purpose is to put Deleuze and Guattari's form-event assemblage within the stratification of regimes of signs in A Thousand Plateaus, in order to establish a ‘natureculture’ continuity not only between science and art, but also between a Western rethinking of language/culture and a Chinese ecosystem/ecocriticism. (shrink)