Scientific Blackpill: Difference between revisions

* 4,000 to 8,000 years ago, women's effective population size grew substantially to around 17 times the size of men's.

* A conceivable explanation is increasingly polygynous mating practices enabled by the power concentration and wealth of farmers. Hereditary systems of political and religious succession, e.g. chiefdoms, hereditary priesthood, early monarchies, also likely contributed to increasing wealth inequality and hence variance of reproductive success among families of different economic standing.

Note: This study was ''misquoted'' by Pacific Standard (psmag.com) and others to imply that ''17 women reproduced for every one man'' (see Cochran, 2015). In truth, only the ''effective population size'' of women was 17 times as large as men's. The effective population size does not clearly distinguish parents and their descendants due to the similarity of their genes. A man with 40 children, each of which has 20 children in turn, would not contribute with 1 + 40 × 20 = 801 individuals to the effective population size, but considerably less than that. Assuming a child inherits half of the fathers genes, the effect on genetic diversity is as if the man produced close to 1 + 40 × 0.5 × 20 = 401 children (instead of 40) and even more when including all his descendants. Since women's fertility is much more limited, this increases the F:M ratio.

The result still points to substantial sex differences in variance of reproductive success. Reputed social psychology professor Roy Baumeister, estimated the sex ratio of historical reproductive success to be 2:1. Half the branches on a tree of ancestors represent males, but half of the males are repeats. Possibly 80% of women, but only 40% of men (i.e. half as many) have reproduced. The observation that males (humans and in the animal kingdom in general) exhibit a greater variance in reproductive success as compared to females is known as [[Bateman's Principle]].

*Karmin M, Saag L, Vicente M, Sayres MAW, Järve M, Talas UG, et al. 2015. ''A recent bottleneck of Y chromosome diversity coincides with a global change in culture.'' Genome Research.  25: 459-466. [[https://genome.cshlp.org/content/25/4/459.abstract Abstract]] [[https://genome.cshlp.org/content/25/4/459.full.pdf+html FullText]]