FERTILITY TRANSITION, SOCIOECONOMIC DETERMINANTS OF

To understand the amazing decline in fertility–the average number of births per woman–in modern times, it is necessary to begin with an examination of high fertility in traditional societies. Fundamentally, fertility was high, typically around five to seven births per woman, because of high death rates. Without high fertility, most societies would have experienced population decline and eventual disappearance. The necessity of high fertility for the survival of the community does not imply that most persons had a conscious awareness of the relationship. Rather, the desire for high levels of childbearing was woven into the cultural fabric and the social institutions of traditional societies.

In addition to strong cultural inducements for marriage and childbearing, the well-being of the family in traditional societies was dependent on having several children who survived to adulthood. Families were the primary economic units as well as reproductive unions. Children were a valued source of household labor and were also the preferred means to guarantee the old-age security of parents. In societies without formal schools, mass media, and modern transportation, family relationships and interactions were the center of social and cultural life. Larger extended families provided more companionship, a wider circle of trust, more protection in times of trouble, and a higher status for patriarchs and matriarchs than did smaller families.

The population problem in traditional societies was maintaining some sort of rough balance between births and deaths. If population decline could threaten community survival, a long period of increasing population numbers would likely outpace the expansion of food and other resources. Although population growth averaged close to zero over long stretches of human history, there were periods during which population size increased across generations. In many cases, out-migration to frontier regions reduced population pressure, but all too frequently it was crisis mortality that brought population numbers back in line with subsistence levels.

These episodes of famine, plague, and war were labeled by the English economist T. R. Malthus (1766–1834) as positive checks, which he thought were inevitable, given the tendency for populations to grow faster than the means of subsistence. The only way to avoid these dismal cycles of demographic growth and implosion, Malthus argued, was through preventive checks, of which the only acceptable variants were moral restraint that encouraged celibacy and the postponement of marriage. Malthus was pessimistic, however, that moral restraint would be sufficient to avert positive checks because of the underlying "passion between the sexes." Malthus was partially right. His pessimistic scenario of expansion and decline did characterize the population dynamics of many premodern societies, although periods of growth could be accommodated for decades or even centuries, depending on the technology of production, the possibilities for long-distance trade, and the size of the frontier. Moreover, plagues, famines, and wars often followed their own dynamics, independent of population size and growth.

The major failing of Malthus's argument, however, was to not notice that even high fertility of five to seven births per woman was well below the maximum number of births (some 15 or 16) that might occur if there were no restraints on childbearing. In all societies, fertility (or infant survival) is held in check in varying combinations by delayed age at marriage, by some proportion of the population never marrying, by long periods of breast-feeding (which suppresses ovulation), and by cultural proscriptions that affect the frequency and timing of sexual intercourse. Folk methods of birth control together with abortion and infanticide would often have also played a role. Such practices, especially delayed age at marriage, reduced fertility in many traditional western European societies by the eighteenth and nineteenth centuries to levels of only four to five births per woman–in circumstances in which the probability of survival to adulthood may have averaged only around 50 percent. The variations in "high fertility" across societies and over time suggest that fertility was regulated in response to socioeconomic conditions and ecological constraints, although most couples may not have been consciously controlling family size.

The major turning point in world demographic history, and the conclusive break from Malthus's predicted cycle, was the sustained declines in fertility that began in France and North America early in the nineteenth century and elsewhere in western European countries around 1880 and that led to small families that averaged about two births per couple by the third decade of the twentieth century. Demographers label a fertility rate of about two births per woman as replacement-level fertility because two children, in the contemporary context of low mortality, are sufficient to replace their parents in the next generation. The transition from high to low fertility was not only an unprecedented demographic revolution but also a cultural revolution with profound implications for the definition of the family and the adult roles of women and men. Modern societies are still in the process of adapting old (and creating new) institutions and gender roles in the wake of the relatively recent transition to low fertility.

About a hundred years after the beginnings of fertility declines in western Europe–declines that with varying delays soon also spread to the rest of that continent–a similar process began in the developing countries of Asia, Latin America, and Africa. This second wave of fertility transitions began soon after the end of World War II in Japan and in the late 1960s and early 1970s in a few other East Asian countries and small island societies. By the 1990s, fertility declines had begun in almost every part of the globe, including areas of persistently high fertility in South Asia and sub-Saharan Africa. Although most of these fertility transitions were still in process and some had far to go by the early twenty-first century, a generalized low-fertility world was in sight. Replacement-level fertility was achieved in some East and Southeast Asian countries in the 1980s and 1990s, and the United Nations assumed (in its medium variant projection series) that almost all developing countries would have below-replacement-level fertility or below replacement fertility by the middle of the twenty-first century.

Demographic Transition Theory

The theoretical task of explaining modern fertility transitions as a consequence (or a delayed consequence) of declines in mortality and of the socioeconomic changes that have transformed rural agrarian societies into modern industrial societies has been the central question of the scientific field of demography. Although some of the basic ideas can be traced back to the first half of the twentieth century and the works of Warren Thompson (1887–1973), Adolphe Landry (1874–1956), and Kingsley Davis (1908–1997), Frank W. Notestein (1902–1983) wrote the classic statement of demographic transition theory in 1953. The central thesis of the theory was generally presented as a three-stage model: the first stage consisting of pretransition societies characterized by high fertility and mortality; a second transitional stage, consisting of societies with declining mortality and, after a lag, declining fertility; and a third and final stage, consisting of posttransitional societies, which lave low mortality and fertility. Although sometimes framed as more of a descriptive account of what has happened, demographic transition theory, as presented by Notestein, was a sophisticated interpretation of how fertility declined in response to declining mortality, the reduced role of the family in economic organization, the growing independence of women from traditional roles, and the shift from customary behavior to calculative rationality spurred by popular education.

Until the 1970s, the theory of the demographic transition was almost universally accepted by demographers and was widely disseminated in introductory textbooks through stylized graphs and an interpretation of declining fertility in response to the modern forces of industrialization, urbanization, and literacy. These processes had occurred in many Western countries during the nineteenth and twentieth centuries and were presumed to be on the near-term horizon of many developing countries. Relative to other theories in the social sciences, demographic transition theory represented one of the most ambitious and convincing interpretations of the momentous social changes of modern times.

The general formulation of demographic transition theory, sometimes summarized as a list of independent variables associated with urbanization, industrialization, and modernity, was often an inadequate guide to cumulative empirical research. Because the many indicators representing the key causal forces were considered interchangeable (and because the unit of analysis was at best vaguely defined), many of the specific hypotheses of the theory, such as the changing cost of children in rural and urban environments, were rarely differentiated from the broader story about industrialization and urbanization. The net result was that in spite of a proliferation of empirical studies, often with contradictory results, relatively few refinements were made to demographic transition theory.

There were, however, two major essays, published by Davis in 1963 and by Ansley Coale (1917–2002) in 1974, that marked major advances from the standard formulation of demographic transition theory. Davis's "theory of change and response in modern demographic history" aimed to broaden the scope of the theory to include, in addition to declines in marital fertility (the standard empirical focus), the variety of ways that populations respond to population pressure (because of declining mortality) in a context of possibilities for socioeconomic mobility. Although declines in mortality and progress toward modernization typically reduce marital fertility (through increasing use of contraception and higher rates of abortion), Davis noted that postponement of marriage, increasing rates of celibacy, and out-migration were also part of the demographic repertoire of adaptation to population pressure. Davis suggested that the timing of the onset and the pace of fertility declines vary across societies (and regions in a society) depending on the relative weights of these responses. Although there have been a few empirical tests of Davis's hypotheses, his "systems approach" to demographic theory is more admired than empirically addressed.

Based on his observations of the varied patterns of fertility decline in late-nineteenth-and early-twentieth-century Europe, Coale suggested that fertility declines were affected not only by socioeconomic change but also by the cultural context of the society. In an influential formulation he specified three preconditions for fertility decline (summarized by others as "ready, willing, and able"): (1) "fertility must be within the calculus of conscious choice," (2) "reduced fertility must be advantageous," and (3) "effective techniques of fertility reduction must be available" (Coale 1973, p. 65). Demographic transition theory had primarily focused on the second pre-condition, namely that there must be a perceived socioeconomic gain to motivate couples (women) to want fewer children. Presumably, changes in reproductive motivations would follow from industrialization, urbanization, and other changes in social institutions that lower the economic advantages (or increase the costs) of children.

The first and third preconditions noted by Coale point to factors that had been largely taken for granted by demographers–factors that are irrelevant if the second condition is not satisfied and readily forthcoming if it is. By fertility being within the calculus of conscious choice, Coale meant there must be social legitimation for the idea of fertility regulation before most couples will act in ways that challenge traditional values of having a large family. This assumption is supported by the 1986 finding of Ron Lesthaeghe and Chris Wilson that secularization (measured by voting for nonreligious political parties) was a very important determinant of the timing of fertility decline, net of economic factors, across provinces in Europe. In deeply traditional societies with few external influences beyond the family and religious authorities, couples may not think there are any choices to be made. The third precondition is that couples know how to regulate fertility. The presence of knowledge of fertility limitation in a society does not mean that all (or even most) couples actually knew how to practice fertility control. With the massive diffusion of information about birth control and the contraceptive supplies and services distributed through family planning organizations and private channels in most contemporary societies, Coale's first and third preconditions are probably less consequential for the modern wave of fertility transitions than they were for the earlier transitions.

Alternative Theories of Fertility Decline

In the 1970s and 1980s, two streams of demographic research directly challenged the hegemony of demographic transition theory. The first was the surprising findings from the Princeton European Fertility Project, initially noted in a 1979 article by John Knodel and Etienne van de Walle and later discussed in detail in the project's 1986 summary volume by Coale and Susan Cotts Watkins. Although the European Fertility Project was envisaged as an empirical test of transition theory on its original home ground, the results showed that the pace of fertility decline across provinces and regions of Europe was only modestly correlated with the socioeconomic variables that figured so prominently in the standard theory. Instead, the patterns and pace of fertility decline appeared to be more associated with regions that shared common languages and culture than with regions sharing common socioeconomic features.

The second challenge to demographic transition theory came from the results of comparative analyses of data from the World Fertility Survey (WFS) project. The WFS project consisted of cross-sectional studies of individual-level correlates of fertility behaviors, attitudes, and contraceptive practice in dozens of developing countries around the globe. Although these studies showed that, in general, fertility was correlated in the expected direction with female education, urban residence, and other socioeconomic variables, the relationships were often modest and many exceptions could be found. Following on these findings and the research of Lesthaeghe, John Cleland and Chris Wilson wrote a bold essay, published in 1987, that questioned the empirical validity of demographic transition theory and suggested that an alternative model of culture and fertility, labeled ideational theory, would be a more appropriate theoretical framework. Ideational theory holds that cultural values are the primary influence on fertility. In some cases, cultural values supporting high fertility may be only slowly (and partially) eroded by socioeconomic changes. In other situations, cultural values that shape fertility behavior can change rapidly with the diffusion of ideas independently of socioeconomic change.

There has also been a proliferation of other new theories and accounts of modern fertility transitions. One of these is John C. Caldwell's theory of inter-generational wealth flows. Caldwell posits that mass education and Westernization (values communicated through the mass media and cinema) have popularized the idea of "child-centered" families that reduce the flow of wealth, services, and other valued resources up the generational ladder. Because these changes have made children less valuable, there are fewer incentives to have large families. Another, very influential, theoretical direction was suggested by the application of microeconomic theory to household decision-making regarding choices to have children. And Richard Easterlin has attempted to integrate the economic and sociological approaches to fertility change in a model that takes account of the demand for children, the "supply" of children, and the cost of fertility regulation.

Although there are many insightful ideas and considerable intellectual excitement in the new theoretical literature on fertility transitions, it is sometimes hard to tell what is fundamentally new and what is merely the repackaging of earlier ideas. Karen Oppenheim Mason cogently argued in 1997 that much of the debate on the causes of fertility transitions is in fact concerned with variations in the proximate conditions that influence the timing of fertility declines, and that there is broad agreement over the long-term historical factors, especially mortality decline, that have led to fertility transitions. The portrayal of demographic transition theory as a universal model of modernization and fertility decline is probably too general and vague, but there is a considerable body of evidence that socioeconomic development has been more influential in shaping historical and contemporary fertility declines than many critics have acknowledged.

There are, of course, considerable variations in the timing of the onset and the pace of fertility declines across populations, and across groups and regions within populations, and these variations are often associated with cultural and linguistic factors. The influences of socioeconomic and ideational factors need not, however, be considered as opposing hypotheses, but rather as complementary elements of an integrated theory of fertility change. Fertility, and population growth more generally, clearly respond to societal pressures that threaten the survival and well-being of human communities. Although there is much evidence that socioeconomic development is associated with fertility change in many (but perhaps not all) societies, there is ample room to consider additional hypotheses for other social and cultural factors that influence demographic change in varied circumstances. Observing the rapid spread of fertility transition to almost every region and country, at highly varied levels of socioeconomic development, Cleland concluded in 2001 that declines in mortality are the most likely common cause.

The impact of public intervention, particularly family planning programs, on fertility trends continues to be debated. The conventional wisdom, initially proposed in the classic 1976 study by Ronald Freedman and Bernard Berelson, is that the combination of vigorous family planning efforts and a favorable socioeconomic setting produce conditions most likely to lead to lowered fertility. Nevertheless, the task of sorting out the independent and joint effects of setting and policy has been remarkably elusive. The initiation of family planning programs tends to be an inherent part of the process of development itself, and it is difficult to obtain independent empirical assessments of each. Successful governments tend to have effective public programs, including well-managed family planning programs. Within countries, family planning clinics are not distributed randomly but are typically placed in areas of high fertility. Thus, the bivariate (two-variable) association between proximity to family planning services and level of fertility is usually positive. The results of more complex multivariable models are heavily dependent on initial assumptions and the analytical formulations: Several studies show only modest effects of family planning programs; others have reported more positive assessments.

The end of fertility transition was never defined beyond the general expectation that low fertility would approach the replacement level (around two children per couple) within some modest range of fluctuation. This has generally been the case in the United States: The total fertility rate (births per woman) dropped slightly below two births per woman in the mid-1970s, and then rose slightly to around two in the 1990s. In Europe, however, fertility continued its downward descent and by the late 1990s was well below the replacement level and showing no sign of rising. In some eastern and southern European countries in the early twenty-first century, average fertility, as measured by the period total fertility rate (the number of children a woman would eventually bear if current fertility rates persisted) appeared to be approaching one child per couple. One school of thought holds that this is a temporary phenomenon, driven primarily by poor economic conditions and a temporary rise in the average age of childbearing. If fertility is merely being postponed and most couples will eventually have two births, then in the early twenty-first century period measures of fertility are not an accurate prediction of the future. Indeed, survey data on fertility expectations show that most women in industrial societies still want to have two children. But other observers believe that the costs of childbearing (socially and economically) are so high in modern industrial societies that below-replacement fertility is likely to continue indefinitely, with the prospect of declining population size.

Conclusions

The first fertility transitions began in the nineteenth century, and average fertility levels reached about two births per woman in a few western European countries in the early decades of the twentieth century. At the dawn of the twenty-first century, the dominant trend is of a global fertility transition throughout the developing world and a sudden drop to below-replacement-level fertility in many European countries. At first glance, these trends suggest the conclusion that modern fertility transitions are among the most dramatic social changes in human history, yielding a new demographic metabolism that is remolding the character of the family and gender roles.

On the other hand, it is possible to interpret modern fertility transitions as corrective adjustments that are returning the human population to a stationary state where, over the long term, the number of births is approximately equal to the number of deaths. Even with high fertility, most families in premodern societies were of modest size because of high mortality. According to this perspective, the dominant demographic change of the last century is not the decline of fertility, but the rapid increase in population during the transition from the general stability of high morality and fertility to the emerging balance of low mortality and fertility. After several centuries of rapid social change and accelerating demographic growth, the world population reached approximately 1.6 billion in 1900. During the fateful twentieth century, the population of the world grew fourfold to the once barely plausible number of 6 billion in the year 2000. Even with continued slowing, the momentum of population growth is likely to add an additional 2 or 3 billion to the global total by the middle of the twenty-first century. The implications of this era of growth on the human condition and Earth's resources are only slowly being understood.

Both of these apparently different perspectives are valid, and together they suggest why it is so difficult to explain modern fertility transitions. There is no single path that has been common to all the societies that have experienced (or are currently experiencing) declines in fertility. Although population pressure from declining mortality may be the most common factor across societies, there are wide societal variations in the pace of socioeconomic development, the relative role of government and private markets, cultural traditions and gender stratification, and the strength of family planning programs. As Freedman suggested in 1979, there is likely to be a variety of conditions that are "sufficient" to lead to lowered fertility. With further study of these variant conditions and their fertility outcomes, past and future, there is the prospect of creating a simpler, but more comprehensive theory of fertility transition as the central element in understanding world demographic history.

See also: Coale, Ansley Johnson; Culture and Population; Davis, Kingsley; Demographic Transition; Development, Population and; Freedman, Ronald; Homeostasis; Landry, Adolphe; Mortality-Fertility of Relationships; Notestein, Frank W.; Thompson, Warren S.

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Charles Hirschman