The earliest recorded fertility transition: lessons for future progress

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The earliest recorded fertility transition: lessons for future progress

Guillaume Blanc
Assistant Professor of Economics at The University of Manchester and the co-founder and deputy director of The Arthur Lewis Lab for Comparative Development. His research explores the role of cultural factors in the transition from stagnation to growth and the institutional origins of common language and national identity in diverse societies.”

The world is currently witnessing a major, global demographic shift, with the prospects of depopulation looming. From the staggering collapse of South Korea’s birth rate and forecasts of China’s population halving by the end of the century, to broader concerns about aging societies, fertility decline is sparking concerns about future human progress and societal stability. But are these concerns well-founded? Does a decrease in fertility inevitably lead to economic decline and societal collapse?

To answer this question, it is important to understand history and the forces and mechanisms that have set the human journey into motion. Since the emergence of modern humans about three hundred thousand years ago in East Africa, and until the nineteenth century, human existence was a harsh and unforgiving ordeal, ‘nasty, brutish, and short’, marked by starvation, poverty, wars, and pandemics. While sporadic innovations occasionally emerged, these advances primarily resulted in larger populations rather than substantial improvements in the quality of life. Whenever innovations took place, temporarily raising income, fertility increased and standards of living bounced back to subsistence levels. This grim outlook led Thomas Malthus in 1798 to dismally conclude that humanity was destined to endure perpetual stagnation.

Malthus was proved wrong. The burgeoning population, instead of serving as a barrier to progress, became a catalyst for innovations. This set in motion a positive feedback loop, intricately intertwining technology, population growth, and education. Oded Galor argues, in The Journey of Humanity (2022), that these forces operated silently but persistently throughout human history, gradually gaining momentum. During the Industrial Revolution, technological advancements reached a tipping point where basic education became imperative for individuals to adapt to the evolving technological landscape. The demand for human capital triggered a quantity-quality trade-off and ultimately the decline in fertility during the demographic transition, an essential condition for development marking the escape from millenia of malthusian stagnation. Population growth no longer offset gains in living standards, paving the way for long-term prosperity.

My research uses the earliest fertility transition in history as an experiment to understand the role of cultural factors in the transition from stagnation to growth, and ultimately understand if population decline will necessarily lead to declining growth. The demographic transition began in France in the eighteenth century, before the French Revolution and more than a century earlier than in any other country. Why and when this happened remain some of the ‘big questions of history’ according to Harvard historian Robert Darnton.

Because it happened so early, this event has posed challenges to traditional explanations that view development as the best contraceptive and argue that fertility declines when the returns to human capital rise. As societies become more technologically advanced, the value of human capital increases, and individuals invest more in education and skill development rather than in having large families. However, France was a stagnant economy in the eighteenth century, while Britain was the cradle of the Industrial Revolution. Additionally, the lack of comprehensive data before contemporary censuses became available has hindered a more profound understanding of its characteristics and the factors driving it.

Cronología del descenso de la fecundidad

Fig 1. Cronología del descenso de la fecundidad (utilizando los datos censales disponibles después de 1830)

To estimate the timing of the transition, I leverage publicly available crowdsourced genealogies from The data stems from users who construct family trees using scanned handwritten birth, marriage, and death records of their ancestors. I meticulously cross-reference these genealogies with the best available representative data on urbanization, fertility, and mortality and find that the genealogical data is highly representative of the broader eighteenth and nineteenth-century population and contain ordinary individuals of that era.

Using this data, I estimate that the fertility decline began in the 1760’s in France, a decade earlier than was previously thought and a century ahead of other countries. In the middle of the eighteenth century, France was the China of Europe, with 25 million inhabitants and one of the highest population densities in the world. In contrast, England had a mere 5 million inhabitants. If France’s population had increased at the same rate as England’s after 1750, the country would now be home to over 250 million people.

What could have happened? I advance the hypothesis that the waning influence of the Catholic Church played a pivotal role in the early fertility decline, and ultimately in the diffusion of the transition across countries. Drawing on a wide range of data and sources, including wills that people left before they died, I document an important process of secularization that took place in France in the eighteenth century. Towards the end of the seventeenth century, wills frequently invoked God, Paradise, and saints, but on the eve of the French Revolution, a shift occurred. More secular language, for example describing death as the ‘indispensable tribute we owe to Nature,’ became prevalent. Additionally, various religious practices, including requests for requiem masses, charitable bequests, offerings to the church, invocations of the Virgin Mary, and even the average weight of funeral candles, markedly declined, indicative of a broader societal shift towards secular values.

Utilización de datos genealógicos para documentar la transición histórica de la fecundidad

Fig 2. Utilización de datos genealógicos para documentar la transición histórica de la fecundidad

For centuries, various contraceptive methods, including coitus interruptus, were widely known. However, their use was limited, especially after the Counter-Reformation held sway in Europe, with the Catholic Church emphasizing procreation in marriage. As the influence of the Church waned, the clergy could not oppose fertility controls. Using census data available almost a century after the onset of the transition, my analysis reveals a robust link between secularization and the fertility decline. Secular regions witnessed a significantly earlier decrease in fertility compared to their non-secular counterparts. The contrast between Provence, with a strong embrace of secular values, and Brittany, a bastion of Catholicism, is nearly as pronounced as the contrast between France and England.

Using the genealogical data, I also find results suggesting that the relaxation of social and moral constraints played a significant role at the individual level. By looking at the effect over time and tracing migrations, I also find that regions that had lower fertility after secularization took hold did not have higher fertility before, and that individuals born in places with higher fertility but moved later transmitted their cultural norms to their children, even though they were born and raised in a different environment. For example, interestingly, most of the migration from France to Quebec took place before secularization took hold and from the regions of France that later became secular. Because secularization had not taken place at the moment migrants left, they brought norms of high fertility to Canada. In Quebec, norms of high fertility persisted until the Quiet Revolution led to secularization and rapid fertility decline in the 1960’s.

The spread of secular values and beliefs, whether it was disenchantment or a more profound backlash against the clergy or the values of the Church, affected the whole of society in France, and later most of the Western World, and played a major role in the transition to sustained economic growth. Although it happened during an age of progress in which a view of the world where man could command and understand nature emerged among some elites, this process was distinct from the Age of Enlightenment, which only affected a handful of philosophers, aristocratic elites, or a limited portion of the bourgeoisie.

Last but not least, my research delves into the driving factors behind secularization and uncovers evidence of a backlash against entrenched elites, particularly religious authorities who held a monopoly on faith and maintained close ties with an absolutist, divine-right monarchy. This alliance effectively granted a monopoly to the Counter Reformation, centuries before the sweeping changes witnessed in eighteenth-century France. I document this using data on the presence of the Holy League, an organization whose aim was to eradicate Protestants from France and fought a civil war against the future King of France, Henry IV, eventually forcing him to convert to Catholicism to access the throne, and data on the extractiveness of the gabelle, a system of forced taxation of salt, with a tax rate that varied widely across space. I find that, in areas where the influence of the Holy League was robust in the sixteenth century, and where institutions promoted inclusivity rather than extraction, such as Brittany, there continues to be a notable presence of religious devotion today. In contrast, regions characterized by both extractive institutions and a significant Counter Reformation influence, such as Paris and Provence, have evolved towards secularism in the eighteenth century.

El crecimiento económico tras la transición

Fig 3. El crecimiento económico tras la transición

The demographic transition served as a catalyst for France’s leap forward, positioning the nation to catch up with Britain, the birthplace of the Industrial Revolution. I show that, after the fertility transition, France was able to grow real per capita income as fast as England did. This resonates with the challenges of today: low fertility need not herald economic decline, provided it translates into investments in education and human capital, facilitating a shift from quantity to quality and a transition towards modernity.