Darwin’s Children

How evolution may cause our species to bifurcate

Image credit: AP x 90 on Unsplash

As best as we can tell from archeological evidence and DNA analysis, for around 96% of human history our choice of mate was largely restricted by geography. Aside from nomadic tribes, nearly all the people who’ve lived and died since we emerged as a distinct species have done so within a five kilometer radius of where they were born.

This means that proximity has played a dominant role in human mate selection and hence in the genes that have been passed down through the ages. There may be “the right one” out there for everyone, but if we’re stuck within the confines of a small hunter-gatherer group or in a rustic hamlet our entire lives the overwhelming probability is that we’ll end up with the nearest least-worst option available.

Since the Industrial Revolution, however, things have changed dramatically. As people congregated in ever-larger cities mate selection options expanded, albeit tightly constrained by class and economics. For all the fairytales about princes marrying paupers, the reality is that nearly everyone married within their socio-economic bracket. Still, even allowing for this, mate selection possibilities increased.

The most dramatic shift has occurred since 1945 in developed nations. As more women entered the workforce and sought higher…