The Limits to Low Fertility: A Biosocial Approach
Caroline Foster holds degrees in the social and biological sciences and is a doctoral student in demography at Nuffield College, University of Oxford In light of 30 years of below-replacement fertility in many industrialized societies, demographers are asking whether fertility could drop even further, or whether there is a "floor" below which it will not fall. A key unanswered question is whether there may be a variable biological component to fertility motivation which ensures that we continue to reproduce. Drawing on evidence from evolutionary biology, ethology, quantitative genetics, developmental psychobiology, and psychology, the article argues that our evolved biological predisposition is toward nurturing behaviors, rather than having children per se. Humans have the unique ability to be aware of such biological predispositions and translate them into conscious, but nevertheless biologically based, fertility motivation. It is likely that we have already reached the limits to low fertility since this "need to nurture," in conjunction with normative pressures, ensures that the majority of women will want to bear at least one child. A sketch for a biosocial model of fertility motivation is outlined. [26, no. 2 (Jun 00 ) 209–234]
Diane J. Macunovich, visiting Professor of Economics, Department of Economics, Barnard College, Columbia University, New York Using United Nations estimates of age structure and vital rates for 184 countries at five-year intervals from 1950 through 1995, this article demonstrates how changes in relative cohort size appear to have affected patterns of fertility across countries since 1950—not just in developed countries, but perhaps even more importantly in developing countries as they pass through the demographic transition. The increase in relative cohort size (defined as the proportion of males aged 15–24 relative to males aged 25–59), which occurs as a result of declining mortality rates among infants, children, and young adults during the demographic transition, appears to act as the mechanism that determines when the fertility portion of the transition begins. As hypothesized by Richard Easterlin, the increasing proportion of young adults generates a downward pressure on young men’s relative wages (or on the size of landholdings passed on from parent to child), which in turn causes young adults to accept a tradeoff between family size and material well-being, setting in motion a "cascade" or "snowball" effect in which total fertility rates tumble as social norms regarding acceptable family sizes begin to change. [26, no. 2 (Jun 00 ) 235–261]
Zhongwei Zhao, Fellow, Demography Program, Research School of Social Sciences, Australian National University, Canberra The controversy regarding China’s historical residential patterns is related to the lack of investigation into demographic influences on past kinship structures and household formation. This study uses computer micro-simulation to examine demographic feasibility of people living in large multi-generation households under the demographic conditions close to those recorded in Chinese history. It investigates both the composition of households in which individuals live at a particular point in their life course and the transition in their household structure and the length of time they spend in households of different types. The simulation exercise suggests that demographic regimes and household formation systems similar to those operating in China in the past produce diverse residential patterns, in which individuals could experience different household forms at different stages of the life cycle.[26, no. 2 (Jun 00 ) 263–293]
Kate Fisher, Junior Research Fellow, Wolfson College, University of Oxford, and Wellcome Research Fellow, Cambridge Group for the History of Population and Social Structure Evidence from oral history interviews is used to suggest the need to reevaluate our understanding of the dynamics of fertility decisions and behavior in the first half of the twentieth century. Those interviewed stressed their vague and haphazard approach to contraceptive use, in sharp contrast to the dominant depiction in studies of fertility decline that emphasize the degree to which individuals made deliberate and calculated choices about family size based on an assessment of the costs and benefits of childrearing. Details of individual contraceptive strategies elucidate the complexities of birth control behavior: couples, lacking explicit aims for family limitation, adopted diverse methods of birth control, using them for different reasons, at different times, with varying degrees of determination and confidence and frequently with very little direct discussion or planning. Explicit articulation of aims was not a necessary prerequisite of the spread of birth control; accepted gender roles meant that responsibilities and obligations emerged gradually and tacitly. As a result, nevertheless, low fertility was effectively achieved.[26, no. 2 (Jun 00 ) 295–317]
Notes and Commentary D. Gale Johnson, Eliakim Hastings Moore Distinguished Service Professor of Economics Emeritus, University of Chicago Because of the low income elasticity of demand for farm products and the ability of farmers to increase labor productivity, economic growth requires that farm employment decline if farmers are to share in the benefits of such growth. In 1952 approximately 84 percent of China’s workers were engaged in agriculture; in 1997 the figure had declined to 41 percent. By 2030 farm employment may account for only 10 percent of the total. The productivity of farm labor must increase at a rapid pace if the 63 percent decline in farm employment does not adversely affect the rate of growth of farm output.[26, no. 2 (Jun 00 ) 319–334]
Data and Perspectives Jean Drèze, Honorary Professor, Department of Economics, Delhi School of Economics
Reetika Khera, affiliated with the Institute of Development Studies, University of Sussex This study presents an analysis of inter-district variations in murder rates in India in 1981. Three significant patterns emerge. First, murder rates in India bear no significant relation with urbanization or poverty. Second, there is a negative association between literacy and criminal violence. Third, murder rates in India are highly correlated with the female–male ratio in the population: districts with higher female–male ratios have lower murder rates. Alternative hypotheses about the causal relationships underlying this connection between sex ratios and murder rates are scrutinized. One plausible explanation is that low female–male ratios and high murder rates are joint symptoms of a patriarchal environment. This study also suggests that gender relations, in general, have a crucial bearing on criminal violence.[26, no. 2 (Jun 00 ) 335–352]
- Leta S. Hollingworth on Coercive Pronatalism
- The Predicament of Population Aging: A Review Essay on Peter G. Peterson, Gray Dawn: How the Coming Age Will Transform America—and the World, reviewed by F. Landis MacKellar
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by the New Old, reviewed by Peter Laslett
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Abortion, and the Federal Government in Modern America, reviewed by Charles F. Westoff
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- Jean Drèze (ed.), The Economics of Famine
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- The UN Population Division on Replacement Migration
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