Sexual Division of Labor in Agriculture

Female agricultural contributions decline with agricultural intensification. We formulate and test a theory of the processes of agricultural intensification that explains a high proportion of the variance in female contributions to agriculture. Five variables show replicable effects across two or more regions of the world. These are number of dry months, importance of domesticated animals to subsistence, use of the plow, crop type, and population density. Of these, the first two are the most powerful predictors of female agricultural contributions, while population density has only very weak effects.
MICHAEL L. BURTON is Professor of Anthropology. School of Social Sciences. University of California. Irvine. CA 92717.
DOUGLAS R. WHITE is Professor of Anthropology. School of Social Sciences. University of California. Irvine.     

A Bioeconomic Approach to Marriage and the Sexual Division of Labor

Children may be viewed as public goods whereby both parents receive equal genetic benefits yet one parent often invests more heavily than the other. We introduce a microeconomic framework for understanding household investment decisions to address questions concerning conflicts of interest over types and amount of work effort among married men and women. Although gains and costs of marriage may not be spread equally among marriage partners, marriage is still a favorable, efficient outcome under a wide range of conditions. This bioeconomic framework subsumes both cooperative and conflictive views on the sexual division of labor. We test hypotheses concerning marriage markets, assortative mating, and men’s labor motivations among Tsimane forager-horticulturalists of Bolivia and find that: (1) men and women both value work effort in marital partners, (2) marital labor contributions are complementary, (3) work effort is correlated between spouses, (4) total production is correlated with total reproduction, and (5) better hunters have higher fitness gains within marital unions.     

Fishing and the Sexual Division of Labor among the Meriam

Do men and women forage differently because they are cooperatively responding to children's requirements for care or because they are differentially sensitive to variance? In this article, I examine how care trade-offs and variance contribute to gender differences in fishing strategies among Torres Strait Islanders (Meriam). Women's fishing had lower failure rates, coefficients of variation, and frequencies of sharing than men's fishing. Men and women responded to trade-offs between mean and variance differently: Women spent less time on high mean–high variance activities, men less time on high mean–low variance activities. Although child-care trade-offs affected time allocation to different fishing activities among women, they did not affect differences in time allocation between the sexes. These results support previous work implicating variance and sharing frequency as important resource currencies shaping gender differences in subsistence decisions, and they offer challenges to a general model of the division of labor predicated on economic notions of specialization as increasing production efficiency.     

The Identity Division of Labor in Native Alaska

ABSTRACT  There is often an implicit assumption that womens' technologies and associated tasks in subsistence-based groups are expedient and simple. For instance, in Native Alaska, the butchering of fish has been illustrated as arduous but uncomplicated work. On the contrary, closer examinations, as well as discussions with the people who are still learning and practicing subsistence tasks, indicate that this perspective is inaccurate. Instead, these taken-for-granted technologies and techniques require a lifetime of training and practice, and not all people achieve master status. Drawing from data from contemporary herring processing and the related tools of the trade, I explore the division of labor in the context of expertise and apprenticeship. [Keywords: apprenticeship, expertise, gender, age, Alaska]     

Religion and Social Structure in The Division of Labor

The article offers a thoroughgoing reinterpretation of The Division of Labor, focusing on the six-stage theory of sociocultural change that lies in the background of Durkheim's well-known contrast between the ideal types of mechanical and organic solidarity. Durkheim's characterization of each stage is described in terms of its structural-functional differentiation and religious unity. The Division's evolutionary theory, which underlies much of Durkheim's mature work, is criticized for its dated ethnographic evidence, and contrasted with alternative evolutionary proposals, including that of sociobiology.     

Sexual dimorphism in the pelves of African lorises

The present study is the first describing sexual dimorphism in the pelves of prosimian primates. Various measurements and indices indicate that there is no significant sexual dimorphism in the pelves of African lorises (Perodicticus potto and Arctocebus calabarensis). The lack of even a moderate degree of sexual dimorphism can be interpreted as the result of a lack of marked sexual differences in body size and of absence of selective pressure for expansion of the birth canal, the latter due to the small size of the fetus at term in relation to the dimensions of the female pelvic inlet.     

A Test of Spatial Autocorrelation Analysis Using an Isolation-by-Distance Model

Using the isolation-by-distance model as an example, we have examined several assumptions of spatial autocorrelation analysis applied to gene frequency surfaces. Gene frequency surfaces generated by a simulation of Wright's isolation-by-distance model were shown to exhibit spatial autocorrelation, except in the panmictic case. Identical stochastic generating processes result in surfaces with characteristics that are functions of the process parameters, such as parental vagility and neighborhood size. Differences in these parameters are detectable as differences in spatial autocorrelations after only a few generations of the simulations. Separate realizations of processes with identical parameters yield similar spatial correlograms. We have examined the inferences about population structure that could have been made from these observations if they had been real, rather than simulated, populations. From such inferences, we could have drawn conclusions about the presence of selection, migration and drift in given natural systems.     

Sexual differences in the anterior dentition in African primates

A study was made of ranges of variation of the anterior dentition of various African nonhuman primates. Comparisons of the dentitions were made between different species and sex differences within each species were determined. Among the nonhuman primate groups studied were: Gorilla gorilla gorilla, Pan troglodytes, Pan paniscus, Cercopithecus nictitans, Cercocebus albigena and Colobus badius. In monkeys the canine teeth of the males are considerably larger than those of the females. There are also considerable differences in size in the rest of the anterior dentition. In apes, and specifically only gorillas, distinct sex differences are only found in the maxillary canines. In the chimpanzees, sex differences in the dentition are much smaller and there is considerable overlap in the ranges of variation. There are no fundamental differences in the size of the rest of the anterior dentition in the apes. The present study shows that differences due to sex in the anterior dentition, excluding the canine, are not as great as has been considered. If we consider the fossil record of man, whose morphological complex includes a much reduced canine, the probability will be that sex differences in the rest of the dentition will be negligible. Given the fragmentary nature of the fossil record, it is, therefore, highly unlikely that the determination of the sex of any fossil hominid specimen can be accurately made based solely on the evidence of its dentition.     

Gender Issues in African Agriculture and Sustainable Development

Women Wielding the Hoe: Lessons from Rural Africa for Feminist Theory and Development Practice. Deborah Fahy Bryceson     

Spatial Autocorrelation Analysis of Migration and Selection

We test various assumptions necessary for the interpretation of spatial autocorrelation analysis of gene frequency surfaces, using simulations of Wright's isolation-by-distance model with migration or selection superimposed. Increasing neighborhood size enhances spatial autocorrelation, which is reduced again for the largest neighborhood sizes. Spatial correlograms are independent of the mean gene frequency of the surface. Migration affects surfaces and correlograms when immigrant gene frequency differentials are substantial. Multiple directions of migration are reflected in the correlograms. Selection gradients yield clinal correlograms; other selection patterns are less clearly reflected in their correlograms. Sequential migration from different directions and at different gene frequencies can be disaggregated into component migration vectors by means of principal components analysis. This encourages analysis by such methods of gene frequency surfaces in nature. The empirical results of these findings lend support to the inference structure developed earlier for spatial autocorrelation analysis.     

Analysis of DNA Diversity by Spatial Autocorrelation

Two statistics are proposed for summarizing spatial patterns of DNA diversity. These autocorrelation indices for DNA analysis, or AIDAs, can be applied to RFLP and sequence data; the resulting set of autocorrelation coefficients, or correlogram, measures whether, and to what extent, individual DNA sequences or haplotypes resemble the haplotypes sampled at arbitrarily chosen spatial distances. Analyses of computer-generated sets of data, and of RFLP data from two natural populations, show that AIDAs allow one to objectively and simply identify basic patterns in the spatial distribution of haplotypes. These statistics, therefore, seem to be a useful tool both to explore the genetic structure of a population and to suggest hypotheses on the evolutionary processes that shaped the observed patterns.     

Social Network Analysis Predicts Health Behaviours and Self-Reported Health in African Villages

The provision of healthcare in rural African communities is a highly complex and largely unsolved problem. Two main difficulties are the identification of individuals that are most likely affected by disease and the prediction of responses to health interventions. Social networks have been shown to capture health outcomes in a variety of contexts. Yet, it is an open question as to what extent social network analysis can identify and distinguish among households that are most likely to report poor health and those most likely to respond to positive behavioural influences. We use data from seven highly remote, post-conflict villages in Liberia and compare two prominent network measures: in-degree and betweenness. We define in-degree as the frequency in which members from one household are named by another household as a friends. Betweenness is defined as the proportion of shortest friendship paths between any two households in a network that traverses a particular household. We find that in-degree explains the number of ill family members, whereas betweenness explains engagement in preventative health. In-degree and betweenness independently explained self-reported health and behaviour, respectively. Further, we find that betweenness predicts susceptibility to, instead of influence over, good health behaviours. The results suggest that targeting households based on network measures rather than health status may be effective for promoting the uptake of health interventions in rural poor villages.