Friday, September 07, 2007

In the days of yore the wealthy were healthy and prolific   posted by Razib @ 9/07/2007 09:05:00 AM
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Virpi Lummaa has a paper up at PLOS One, Natural Selection on Female Life-History Traits in Relation to Socio-Economic Class in Pre-Industrial Human Populations:
...We found the highest opportunity for total selection and the strongest selection on earlier age at first reproduction in women of the poorest wealth class, whereas selection favoured older age at reproductive cessation in mothers of the wealthier classes. We also found clear differences in female life-history traits across wealth classes: the poorest women had the lowest age-specific survival throughout their lives, they started reproduction later, delivered fewer offspring during their lifetime, ceased reproduction younger, had poorer offspring survival to adulthood and, hence, had lower fitness compared to the wealthier women. Our results show that the amount of wealth affected the selection pressure on female life-history in a pre-industrial human population.


Lummaa's data is from the 18th and 19th century in Finland, but in many ways it is generalizable. In post-demographic transition societies we are faced with the fact that the lower social classes tend to be more fecund, but for most of human history this was not an operative dynamic. I believe some of the resistance to Greg Clark's contention that the wealthy gentry were the predominant ancestors of the modern British population is simply due to its relative counter-intuitiveness to the modern middle class, who simply can't believe that anyone responsible would breed to their maximal reproductive capacity.

Before Chris Surridge starts riding me, please be aware you can leave comments over at PLOS One!

Pettay JE, Helle S, Jokela J, Lummaa V (2007) Natural Selection on Female Life-History Traits in Relation to Socio-Economic Class in Pre-Industrial Human Populations. PLoS ONE 2(7): e606. doi:10.1371/journal.pone.0000606

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