The Mighty Potato

 

According to the most conservative estimates in this QJE, the introduction of the potato accounts for approximately one-quarter of the growth in Old World population and urbanization between 1700 and 1900.

There is a link to the paper at the tweet by Kweu-Opuku Agyemang, PhD. 

Just one more reminder that we complain a lot about Twitter, but researchers are making great use of it to share knowledge. 

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And from the sidebar there I was intrigued by this:

Economic Consequences of Kinship: Evidence From U.S. Bans on Cousin Marriage

Abstract

Close-kin marriage, by sustaining tightly knit family structures, may impede development. We find support for this hypothesis using U.S. state bans on cousin marriage. Our measure of cousin marriage comes from the excess frequency of same-surname marriages, a method borrowed from population genetics that we apply to millions of marriage records from the eighteenth to the twentieth century. Using census data, we first show that married cousins are more rural and have lower-paying occupations. We then turn to an event study analysis to understand how cousin marriage bans affected outcomes for treated birth cohorts. We find that these bans led individuals from families with high rates of cousin marriage to migrate off farms and into urban areas. They also gradually shift to higher-paying occupations. We also observe increased dispersion, with individuals from these families living in a wider range of locations and adopting more diverse occupations. Our findings suggest that these changes were driven by the social and cultural effects of dispersed family ties rather than genetics. Notably, the bans also caused more people to live in institutional settings for the elderly, infirm, or destitute, suggesting weaker support from kin.

Regular readers will be aware that I am suspicious that they think it is more likely that this is social and  cultural rather than genetic, but I give full credit that they at least considered the genetic possibility, and am willing to change my mind on the subject.  I would like to see evidence from British cities on this, and certainly on Middle Eastern countries before being much persuaded, though. I can only find one instance of first cousin marriage, among the Spinneys in 1800s Nova Scotia, in my family tree, plus a couple of second cousin marriages over the last four centuries.  We seemed to have survived the damage.