Busts of Greek philosophers (Wikicommons, Matt Neale). Did the Ancient Greeks have the highest mean IQ of any human population then and since?
Francis Galton argued that average intelligence had been much higher in ancient Greece than in modern England. He came to this conclusion after comparing the proportion of eminent men in Athens of the fifth century BC with the proportion of eminent men in the England of his day:
It follows from all this, that the average ability of the Athenian race is, on the lowest possible estimate, very nearly two grades higher than our own-that is, about as much as our race is above that of the African negro.(Galton 1869, p. 342)
This high ability was then presumably lost:
We know, and may guess something more, of the reason why this marvellously-gifted race declined. Social morality grew exceedingly lax; marriage became unfashionable, and was avoided; many of the more ambitious and accomplished women were avowed courtesans, and consequently infertile, and the mothers of the incoming population were of a heterogeneous class. (Galton 1869, pp. 342-343)
If we accept Galton's reasoning, Ancient Greeks had the highest mean IQ of any human population, something like 120 or 125. By comparison, Ashkenazi Jews have an estimated mean IQ of 110. But was Galton right? His calculations were criticized at the time, specifically for underestimating the number of Athenian citizens. He consequently revised his calculation downward to 1.5 grades higher, i.e., a mean IQ of 115 to 119 (Challis 2013, p. 56).
That's still impressive. But higher IQ doesn't necessarily imply higher innate intelligence. Conditions in ancient Greece may have simply been better for intellectual discussion, such activity being respected as an activity in its own right. By comparison, intellectual discussion was much more circumscribed in the ancient Middle East, where it was confined to specific people who performed specific duties, most often writing and copying texts at the request of others.
Admittedly, this explanation does not exclude a genetic one. If the cultural environment favors intellectual development, it will tend to reward the most promising people with reproductive success. A scribe is thus praised in a Jewish wisdom book from the second century BC: "Many will praise his understanding; it will never be blotted out. His memory will not disappear, and his name will live through all generations. Nations will speak of his wisdom, and the congregation will proclaim his praise. If he lives long, he will leave a name greater than a thousand." Book of Sirach [39.1-11].
In the ancient world, 'leaving a great name' did not mean being written about by historians but rather having many illustrious children to carry on the family name long after death. Intellectual ability thus co-evolved with a supportive cultural base. Indeed, we humans have co-evolved much more with our cultural environment than with our natural environment (Hawks et al. 2007).
A new yardstick
Galton's conjecture can now be tested with two new research tools:
1. Ancient DNA. Large quantities of genetic data have been collected from ancient human remains and are now being made available to researchers. This year, the Reich lab at the Harvard Medical School released over 2,000 ancient genomes, including 30 from ancient Greece.
2. Polygenic cognitive score. Some gene loci are associated with differences in educational attainment. By examining the variants at these loci and by adding up the ones associated with higher educational attainment, we can calculate a polygenic score that correlates with mean IQ (r = 0.98).
By examining 102 ancient genomes, a research team led by Michael Woodley of Menie was able to chart the evolution of cognitive ability in Europe and Central Asia. His team found that genetic variants for higher educational attainment gradually increased in frequency from 4,560 to 1,210 years ago (Woodley of Menie et al. 2017). Now, with newly released data from the Reich lab, he is leading a research effort to look specifically at ancient Greeks. The results are still preliminary, but they indicate a progressive increase in the polygenic score from Neolithic to Mycenaean times, followed by a decrease. When? We don't know because we lack post-Mycenaean data (Woodley of Menie et al. 2019).
More to come ...
This is a promising avenue for research. In particular, we need:
- A larger sample of modern Greek genomes. This should not be difficult.
- Samples from post-Mycenaean times to the end of Ottoman rule. Was Galton right in placing this cognitive decline during the ensuing Hellenistic and Roman periods? Or did it happen over a longer span of time?
The final published paper should explain at greater length the research team's use of a restricted polygenic score, i.e., a polygenic score based only on those genetic variants that seem causally related to high educational attainment, and not simply associated with high educational attainment. This approach is acceptable if a third party had identified these variants; otherwise, there is a risk of focusing on those variants that support Galton's hypothesis.
Another point: in the presentation of his new project, Woodley of Menie spoke repeatedly about population replacement at various times in the history of ancient Greece (Woodley of Menie et al. 2019). Yet the current thinking is that immigration was historically unimportant in Greece. Present-day Greeks are largely descended from the Mycenaeans, with some later introgression by Slavic tribes and other peoples (Gibbons 2017; Stamatoyannopoulos et al. 2017).
This research is especially exciting because the Reich lab released ancient DNA data not only from ancient Greece but also from elsewhere. History may end up being seen in a new light. For instance:
- Rome probably went through a similar increase in mean intelligence, followed by decline. When did the decline begin? During the collapse of the fifth century? I suspect earlier, perhaps in the third century. The barbarian invasions were both a cause and effect in the collapse of Roman civilization.
- The Enlightenment was due only in part to things like the invention of the printing press, the voyages of discovery, and the founding of universities. These were subsidiary causes that resulted from and supported a more fundamental change: a steady increase in the smart fraction of European societies—the proportion of people who enjoy reading, writing and, above all, thinking.
References
Angel, J.L. (1950). Population size and microevolution in Greece. Cold Spring Harbor Symposia on Quantitative Biology 15: 343-351. doi:10.1101/SQB.1950.015.01.031
Challis, D. (2013). The Archaeology of Race. The Eugenic Ideas of Francis Galton and Flinders Petrie. London: Bloomsbury.
https://www.academia.edu/1520119/Archaeology_of_Race._The_Eugenic_Ideas_of_Francis_Galton_and_Flinders_Petrie_Bloomsbury_2013_
Galton, F. (1869). Hereditary Genius: An Inquiry into Its Laws and Consequences. London: MacMillan.
http://galton.org/books/hereditary-genius/
Gibbons, A. (2017). The Greeks really do have near-mythical origins, ancient DNA reveals. Science August 2
https://www.sciencemag.org/news/2017/08/greeks-really-do-have-near-mythical-origins-ancient-dna-reveals
Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending, and R.K. Moyzis. (2007). Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Sciences (USA) 104: 20753-20758.
https://www.researchgate.net/profile/Henry_Harpending/publication/5761823_Recent_Acceleration_of_Human_Adaptive_Evolution/links/0c9605240c4bb57b55000000.pdf
Stamatoyannopoulos, G., A. Bose, A. Teodosiadis, F. Tsetsos, A. Plantinga, N. Psatha, N. Zogas, E. Yannaki, P. Zalloua, K.K. Kidd, B.L. Browning, J. Stamatoyannopoulos, P. Paschou, P. Drineas et al. (2017). Genetics of the peloponnesean populations and the theory of extinction of the medieval peloponnesean Greeks. European Journal of Human Genetics 25: 637-645.
https://www.nature.com/articles/ejhg201718
Woodley of Menie, M.A., S. Younuskunju, B. Balan, and D. Piffer. (2017). Holocene selection for variants associated with general cognitive ability: Comparing ancient and modern genomes. Twin Research and Human Genetics 20: 271-280
https://www.cambridge.org/core/journals/twin-research-and-human-genetics/article/holocene-selection-for-variants-associated-with-general-cognitive-ability-comparing-ancient-and-modern-genomes/BF2A35F0D4F565757875287E59A1F534
Woodley of Menie, M.A., J. Delhez, M. Peñaherrera-Aguirre, and E.O.W. Kirkegaard. (2019). Cognitive archeogenetics of ancient and modern Greeks. London Conference on Intelligence
https://www.youtube.com/watch?v=UES_tpDxz9A
