World Mythology Does Not Support The Out of Africa Migration

Two more for the annals of lies, damned lies, and statistics

A provocative new paper claims our ancestors’ long walk out of Africa pruned not just their genes but their imaginations. The data, however, tell a different story.

In “Roots of Cultural Diversity,” Galor et al. argue that the out-of-Africa migration reduced genetic diversity outside Africa, which in turn diminished the ability of non-African societies to innovate culturally. It’s a strangely bio-essentialist hypothesis, and even stranger is their choice to support it through global patterns of folklore—a domain where Africa is famously simple and homogeneous. Indeed, Harvard philologist Michael Witzel uses precisely this simplicity to argue that Africa is the root of global mythologies. Yet, Galor and his economist colleagues manage to produce charts implying the opposite:

What’s going on here? As usual, the devil is in the details—or, in this case, the residuals. Let’s dig in.

The hypothesis

Galor et al. start from a well-known observation: the further populations moved from Africa, the more genetic diversity decreased. They boldly extend this idea:

“Drawing on the observed patterns of human migration and their biological repercussions, we hypothesize that this process profoundly influenced cultural evolution, setting the stage for the development of narrower spectra of cultural traits in societies farther from the cradle of humanity in Africa. The diminished range of biological traits along the migratory routes limited societal capacity to adapt to environmental and social challenges, constrained the potential for cultural innovation and expression, and ultimately reduced cultural diversity”

So, their model is: Founder effect → Less genetic/phenotypic diversity → Less cultural innovation → Less cultural diversity¹. Every link raises questions. Is there less phenotypic diversity outside Africa? Traits such as hair and eye color, skin pigmentation, earwax types, and specialized adaptations (e.g., high-altitude living) actually exhibit greater diversity outside Africa. Further, how does biological diversity produce a more innovative culture? Or, if the theory holds, should we interpret South America’s comparative economic challenges as rooted in inferior genetics—lacking the quality of the African gene pool? There are wild implications to their hypothesis!

But scientists can have odd ideas; the virtue of science is that it tests bold claims with hard facts. Cultural innovation can be captured by various measurable proxies: tallest structures built, domesticated animal diversity, number of language families, extent of historical empires, or today’s scientific publication count. All these metrics are readily available—and all clearly contradict Galor et al.’s prediction. Africa lags.

The raw data

Instead, the authors test their model with the nebulous proxy of “folkloric diversity.” This also goes against their prediction:

Notice that within 2,500 kilometers of humanity’s cradle, precisely where the authors expect a cornucopia of genes to yield the richest cultural harvest, folkloric diversity is the lowest globally. For context, that radius covers:

Folkloric diversity peaks only when that circle expands to encompass the Mediterranean’s high cultures (Egypt, Greece, Phoenicia). But they don’t report the raw folklore data in the paper. Not even in the supplementary material. I found the raw data in a draft of their paper. The published paper instead presents a heavily processed measure of folkloric diversity obtained by:

1. throwing out the data from Africa

2. controlling for continent, absolute latitude, caloric suitability, ecological diversity, and whether the culture is from an island.

Now, what does folkloric diversity mean after controlling for all of that? It’s really hard to say. But one could produce just as strong a correlation by measuring distance from the Near East (from which many innovations diffused in the Neolithic) or the Caucus Mountains (where Prometheus was chained for the sin of giving humans technology). There is no reason to connect the folklore residuals to the Out of Africa migration, mediated by some mysterious genetic mechanism.

Indeed, the original data show that distance from Africa explains almost nothing about folklore diversity, with an R² value of just 0.018. But by discarding Africa and controlling for everything but the kitchen sink, the authors inflate this 13-fold to an R² of 0.24 (which is still only a modest effect).

I find the whole exercise extremely dishonest, especially the choice to leave off the raw data in the finished product. It’s frankly surprising how little evidence is required to publish a paper saying South Americans are kind of retarded as long as one plays the Out of Africa trump card.

Case study #2

Recently, an interdisciplinary group (biologists, anthropologists, geneticists, and mythologists, including Yuri Berezkin, creator of the folklore database) published a preprint titled “Worldwide patterns in mythology echo the human expansion out of Africa.” Without diving deeply into their methods, they detect diffusion of Eurasian myths from before the Last Glacial Maximum (around 20,000 years ago). However, they seek to project that signal back to 60 kya on essentially no evidence:

“Since the analysed pre-LGM landscape originated at least 38 kya, and in the absence of extensive contacts between Eurasia and Sub-Saharan Africa in palaeolithic times, we conclude that the demic signal we detect could be as old as 60 kya, the time when the expansion Out of Africa of the ancestors of all present-day non-African populations took place. We further provide a shortlist of such myths, which may provide a core set of mythemes that were already known to humankind 60 kya.”²

See how they jump from 20 kya, to 38 kya to 60 kya. No reason is given to support 60 kya other than the lack of contact between Eurasia and Sub-Saharan Africa. Okay, I’ll bite, how did the domesticated dog get to South Africa? There absolutely was contact! And yet the authors choose a title that links mythology to the Out of Africa migration. The siren song of the Urheimat pierces the heart of the modern academic, and journals continue to launder their wishful thinking.

1. Notice that the model has cultural diversity mediated by innovation. Why not measure cultural innovation directly instead of diversity?

2. One of these is the Rainbow Serpent, which I have written about at length, including a take-down of d’Huy’s argument that the Rainbow Serpent is a pre-OoA god.