Patricia Draper

Father Absence and Reproductive Strategy: An Evolutionary Perspective

Explanations offered by social scientists for the effects of father absence on children are reviewed; certain aspects of these interpretations are found wanting. Another explanation using theory from evolutionary biology is suggested: children show evolved, sensitive-period learning in early childhood which is linked to mothers pair-bond status or to mothers attitude toward males. As a result of childrens perceptions a developmental track is established, which influences expression of reproductive strategy in adulthood. Male children born into matrifocal households exhibit at adolescence a complex of aggression, competition, low male parental investment, and derogation of females and feminity, while females show early expression of sexual interest and assumption of sexual activity, negative attitudes toward males, and poor ability to establish long-term relationships with one male. Male children reared in father-present or nuclear households show less interest in competitive dominance with other males and more interest in manipulation of nonhuman aspects of the environment, while females show delayed sexual interest and activity and a mating strategy directed at locating a male who will invest in her and her offspring.

A Sociobiological Perspective on the Development of Human Reproductive Strategies

A current view in the human sciences emphasizes an understanding of the individual as a representative of a past history of selection for survivorship and reproduction. All of us are descendants of individuals who lived long enough to produce reproductive offspring. Our current generation represents the variable mating success of our ascendants. Some of our grandparents and great grandparents had many offspring, others had only one or two. At each generation there are new opportunities to expand and to contract the genetic contribution of particular individuals to future generations. Since evolution favors those (1) who survive and (2) who are most successful at reproduction, we expect Darwinian theory to be most immediately helpful for comprehending our survivorship, mating, and parenting, while it may be less immediately applicable to domains like religion that are less intimately tied to fitness. In the case of humans, for whom learning plays a central role in differentiating reproductive success from failure, the social circumstances and social lessons we experience play a substantial role in influencing our reproductive behavior, the number of offspring we have, and the manner in which we rear those offspring. Learning also contributes to the social niche we occupy during the lifespan. Attention therefore is increasingly focused by sociobiologists on the evolution of human learning.

African marriage systems: Perspectives from evolutionary ecology

T here are many characteristics of contemporary African societies that puzzle demographers and others concerned with economic and social modernization. One of the most prominent is that the birth rate remains in both urban and rural areas of sub-Saharan Africa in spite of the presence of several factors that supposedly promote lowering of fertility (McNicoll 1980). Some of these factors are increased survivorship of children into adulthood, increased availability of education and levels of educational attainment (for both sexes), increased urbanization, and increased monetarization of the economy via migratory wage labor and cash cropping. Each of these is normally thought to promote the freeing of young people from the control of elders and to foster the development of economically independent nuclear families, close conjugal relations between spouses, and parenting practices with more intense investment in smaller numbers of higher quality children (Caldwell 1977a, 1977b, 1982; Caldwell and Okonjo 1968; Anker et al., eds. 1982; Sudarkasa 1977; Page and Lesthaeghe 1981; see Barkow and Burley [ 19801 and Vining [1986] for further biosocial consideration of demographic transition.) Instead, in much of Africa, not only among country people but among urban populations as well, there persists high fertility and a pattern of parental investment in which both mothers and fathers invest, by Western standards, relatively little in each offspring and pursue a pattern of delegated parental responsibility (Draper and Harpending 1988). Coupled with low investment parenting is a mating patern that permits early sexual activity,

Crowding among Hunter-Gatherers: The !Kung Bushmen

Highly crowded living conditions exist among the !Kung Bushmen, hunter-gatherers who live on the edges of the Kalahari Desert in Botswana and South-West Africa. The !Kung appear to be crowded by choice, and biological indicators of stress are absent. Data indicate that residential crowding alone does not produce symptoms of pathological stress.

Foraging Returns of !Kung Adults and Children: Why Didn't !Kung Children Forage?

Children of the hunting and gathering !Kung San seldom foraged, especially during the long dry season. In contrast, children of Hadza foragers in Tanzania often forage, in both wet and dry seasons. Because we have argued that the economic dependence of !Kung children has important consequences, we must try to understand why they did not forage. Experimental data on foraging by !Kung adults and children show that children would have had to walk far from dry season camps to acquire much food. Interviews suggest that !Kung children risk getting lost if they wander unsupervised into the bush. Thus, foraging without adult company was a poor option for !Kung children. Foraging with adults might have been a better strategy. We calculate the benefits to a !Kung mother if her oldest child accompanied her to the nut groves. Because of the high processing costs, a childs work time was most profitably spent at home cracking nuts.

Birth order, sibling investment, and fertility among Ju/’Hoansi (!Kung)

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.

Women's work, child care, and helpers-at-the-nest in a hunter-gatherer society.

Considerable research on helpers-at-the-nest demonstrates the positive effects of firstborn daughters on a mother’s reproductive success and the survival of her children compared with women who have firstborn sons. This research is largely restricted to agricultural settings. In the present study we ask: “Does ‘daughter first’ improve mothers’ reproductive success in a hunting and gathering context?” Through an analysis of 84 postreproductive women in this population we find that the sex of the first- or second-born child has no effect on a mother’s fertility or the survival of her offspring. We conclude that specific environmental and economic factors underlay the helpers-at-the-nest phenomenon.

Cultural correlates of self perceived health status among Chinese elderly

This study examines self-perceived physical and mental health among 213Chinese elderly who visited the Geriatric Outpatient Clinic of BeijingHospital, the People‘s Republic of China. The study hypothesizes thatcultural factors, specified by family relations, along with demographicfactors, number of diseases, economic well-being, and living conditionshave a significant impact on subjects self-perceived health status.Pearson correlation, linear and logistic regression analyses areperformed. Results indicate that age, number of diseases, perceived familyrespect, neighborhood relations, and percentage of income spent on rentare significant predictors of self-perceived physical health. These samefactors plus preference to live with a son and personal monthly income aresignificant predictors of self-perceived mental health. Socio-culturalimplications of these findings are examined.

Antisocial Behavior and the Other Side of Cultural Evolution

In this chapter we try to formulate a model of the evolution of antisocial behavior in our species, to assess the extent to which out model accounts for current knowledge, and to derive new hypotheses amenable to test. We will paint with a broad brush but we will try to make clear, in what follows, which is theory unsupported or unsupportable by observation, which is observation unexplained by theory, and which is some of both.

Coming in from the bush: Settled life by the !Kung and their accommodation to Bantu neighbors

Fieldwork done in the late 1980s shows that !Kung San are living in settled villages with subsistence based on stock keeping, gardening, government distribution of surplus foods, foraging, and in some cases, employment by neighboring cattle-keeping groups. The !Kung villages differ in the degree of dependence on Bantu neighbors. Four village types are distinguished. The least and most dependent villages contrast on several measures including size of the ethnic !Kung population, adult sex ratio, percent of individuals of mixed parentage, and the availability of primary kin.