Research Brief

Historical Case for Immigrants Sending Home More Than Money

France’s lower fertility rates spread to regions that sent the most emigrants to live there

The study of the impact of immigration on economic, social and cultural norms typically focuses on the immigrants, and the country they move to. When the impact on the country those immigrants leave is studied, it’s often centered on money immigrants send back to family members who remain in the origin country. 

While such financial remittances are massive — an estimated 200 million immigrants globally in 2022 sent more than $647 billion back to family members — there’s another form of remittance that gets less attention: the extent to which immigrants continue to impact their mother country by transmitting back the social and cultural norms of their new home country.

A working paper explores the potential cultural remittance of a highly consequential norm: fertility rates. 

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Taking advantage of a trove of 19th and early 20th century data that has been recently digitized, Paris School of Business’ Mickael Melki, Paris School of Economics’ Hillel Rapoport, Tufts University’s Enrico Spolaore and UCLA Anderson’s Romain Wacziarg gauge whether the fertility patterns throughout hundreds of regions in Europe during that period were influenced by their natives who immigrated to France.

In prior research, Spolaore and Wacziarg noted that France was decades ahead of the rest of Europe in shifting to lower fertility rates. France at this historical juncture was also unique in that it was a magnet for immigrants, and it was less likely the French themselves were the transmission engine for lower fertility rates, as emigration from France was not common. 

In short, France is an intriguing window into the potential transmission of its outlier cultural norm (lower fertility rates) by its migrant population back into their native home regions.

The researchers serve up empirical evidence that suggests France’s lower fertility rate became an export good of sorts, transported into regions of Europe via the connections maintained by migrants into France with their home base. 

“Migrants to France were important vectors of diffusion of a specific cultural trait that was central to the broader process of modernization: the spread of preferences and norms favoring lower fertility,” the authors write.

Detailed Naturalization Records Newly Digitized

Data on immigrants into France has long been available to researchers, via the country’s census records, which date back to the mid-1850s. But that data only includes an immigrant’s country of origin, not the specific region they were from, which would afford a far more granular look at the potential correlation of exposure to France’s pace-setting transition to lower fertility rates and subsequent fertility rates back in their home region.

That’s where the digitization crew at the French National Archives comes into the story. France’s records of naturalizations from the mid-1850s through the 1930s has recently come online, and naturalization records include not just the country of origin but the actual birthplace of immigrants who applied for citizenship.

The research team was able to scrape that data and assign immigrants to France into one of more than 400 regions of origin.

They then leveraged a fertility rate metric established in the landmark Princeton European Fertility Project published nearly 40 years ago. That research computed fertility rates across more than 750 European regions in the 19th and early 20th centuries. 

The PEFP fertility rate index metric divided the actual number of children born to married women at a given point in time by the maximal number of children who could have been born from the child-bearing population. (That divisor was estimated based on the fertility rates among Hutterites, a religious sect that practices no form of contraception.)

Exporting Fertility Norms from France 

Melding those two metrics, Melki, Rapoport, Spolaore and Wacziarg were able to model the interaction between a region’s exposure to migrants to France (their independent variable) to the fertility rate back home (the dependent variable).

In a cross-regional analysis they find that in regions of France where there was a large inflow of migrants, the fertility rate in those migrants’ home regions significantly declined about 20 years later. This transmission of France’s fertility norms back into their home regions was strongest from 1871-1890, following the first big wave of immigration. It was still significant from 1881-1890, but from 1901-1920, as modernization trends became more the norm across Europe, the effect became smaller.

The apparent transmission of France’s fertility norms back to the home region is more pronounced in regions with the highest outflow of natives to France. The researchers broke the regions into quartiles based on emigrants who left for France. They then computed the change in fertility rates for two 20-year periods. In the quartile with the most exposure to French fertility norms, the decline in fertility rates between 1861-1880 and 1881-1900 was on average nearly four times that of the quartile with the least exposure to former residents who had moved to France.

The researchers also had regional fertility data within France to work with. They found that the relative level of fertility in a French region a foreigner moved into also impacted fertility rates back home. Migrants into French regions with a lower fertility rate triggered a bigger fertility rate decline in their home country, compared with migrants who landed in French regions with higher fertility rates. 

Additional analysis layered in other factors to their baseline comparison of a region’s exposure to emigrants who landed in France and ensuing fertility rates back home. They found that relationship was impacted by physical and linguistic distance from France to a migrant’s home country. The closer a region was to France along these metrics, the more it felt the impact of lower fertility rates transmitted by its emigrants, compared with regions farther from France. 

Home Ties

The researchers make a case that there was likely plenty of sustained communication between migrants and their home country to facilitate this cultural transmission. They note the early prevalence of seasonal or temporary migration into France, where workers eventually returned to their home region, as well as migrants who came with longer-term intentions but also returned to their home country in large numbers. 

Moreover, prior research established migrants in France typically married after they arrived. They cite research that found from 1888-1991, 60% of male foreigners married a French woman. This suggests a plausible link between those husbands adopting the fertility norms of their French wives, news of which would often make it back to the home country via return visits or correspondence.

Indeed, prior research has centered letter writing as a significant part of the immigrant experience. Melki, Rapoport, Spolaore and Wacziarg include an interesting related nugget: They dug into data of telegrams sent from France in 1876 to other countries. Regions in France with more migrants generated more international telegrams, suggesting that there was indeed ongoing communication between France’s migrants back to their home regions.

The researchers also extended research by Spolaore and Wacziarg published in 2022 that found a correlation between a region’s level of linguistic similarity to French and its adoption of lower fertility rates in the 19th and 20th centuries. Here too, migrants whose native tongue was closest to French — suggesting easier assimilation into French culture — saw a much sharper decline in their home region’s fertility rate than European regions whose languages were the most “distant” to French.

While this research is centered on the cultural remittance of fertility rates across Europe more than a century ago, it serves as a current day reminder of how countries with net in-migration may be transmitting their societal norms back into the countries their migrant population left.

Featured Faculty

  • Romain Wacziarg

    Professor of Economics; Hans Hufschmid Chair in Management

About the Research

Melki, M., Rapoport, H., Spolaore, E., Wacziarg, R. (2023). Cultural Remittances and Modern Fertility. 

Spolaore, E., & Wacziarg, R. (2022). Fertility and modernity. The Economic Journal, 132(642), 796-833.

Coale, A. J. and Watkins, S. C. (1986). The Decline of Fertility in Europe: The Revised Proceedings of a Conference on the Princeton European Fertility Project. Princeton, NJ: Princeton University Press.

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