Steve Sailer has just posted Michael Woodley of Menie’s lecture (hosted on Edward Dutton’s YouTube) on the cognitive archeogenetics of ancient and modern Greeks at this year’s Psychology Conference.

Explaining the cultural/intellectual decline of Classical Greece is one of the major puzzles of history. One HBD-realistic approach is to approach it from the point of view of historical IQ, which is what Woodley et al. do in this paper.

They acquired polygenic scores for general cognitive ability (POLY COG ) for a sample of 29 Greek genomes spanning the Neolithic, Minoan, Mycenaean, and modern periods. You can see the resultant graph at 25:07. The general trend is an increase in POLY COG from 8,000 years ago to some 3,000 years ago, followed by a prepitious collapse through to the modern day.

This initial research suggests that genotypic Greek IQ was substantially higher during the flowing of Greek civilization during the Classical era, and would seem to lend credence to Francis Galton’s suggestion that the Athenians had an IQ of perhaps 120 relative to a Victorian British mean of 100. For the record, this is a thesis that I have myself expressed some skepticism towards, arguing that Classical Greece’s unprecedented levels of literacy – around 10% of the population (“craftsman literacy”), up from the maximum 1-2% (“priestly literacy”) that had been observed in previous civilizations – was by itself sufficient to explain Greek dominance in world intellectual output from 500BC to the era of Christ. These literacy rates were enabled by Greece’s early adoption of the alphabet, and Greek intellectual potential was further turbocharged by its IQ advantage over the civilization in Mesopotamia and Sumer that exists, and can be observed, to this day (e.g. Celts and Germans may have been brighter even then, but they weren’t going to do anything interesting as small illiterate forest tribes). Basically, Classical Greece was the first civilization to obtain an unprecedented number of literate, relatively (not absolutely) high IQ, and non-conformist people. This allowed them to wrack up a vast number of intellectual accomplishments in record time.

Does my explanation then fall by the wayside? Was Greek success – and consequent decline – the result of an anomalously high IQ 2,500 years ago, and subsequent dysgenic decline?

Possibly. But it’s worth noting that this study is hardly the last word on the matter.

1. n=25 for a period spanning the first 7,000 years is very low. The n=4 (!) for the modern era, I daresay, is almost useless. This needs to be repeated with much larger samples.

2. What were the causal mechanisms?

One explanation that Woodley favors is the theory of population replacement, in which higher IQ groups conquered lower IQ ones. AFAIK this is generally not supported by the archaeological record, at least so far as the transition from Classical Greece to the Byzantine Empire is concerned. Sure, there was some Slavic introgression, especially in Thrace and Greek Macedonia, but it’s unclear how that would have caused IQ decline.

Another explanation is that the Greeks and Romans experienced dysgenic reproduction patterns, with very low birth rates amongst the elites (e.g. what began happening in the French aristocracy from the 18th century). But why did this happen there – and not in, say, England, which did experience a “farewell to alms” eugenic effect? And would this elite fertility collapse have affected higher IQ successful merchants? It didn’t affect the Christian Copts – strongly overrepresented in commerce – in Islamic Egypt, who actually had higher fertility rates than their Muslim neighbors during most of history.