Ancient DNA is shedding new light on the archaeology of the mind. By Peter Frost.
We used to think that cultural evolution simply replaced genetic evolution. In reality, the two have pushed each other forward, even into the time of recorded history. Humans create culture, and culture recreates humans — by selecting those who better fit in and cope with its demands on body and mind.
The mind, in particular, has been shaped by this coevolution with culture. To varying degrees, this has meant:
- processing an increasing volume of written texts and numerical data
- keeping track of interactions with more people, most of whom are not close kin or even friends
- imagining how to make tools for an ever-wider range of tasks
- creating mental models with a longer timeline. Simply put, we no longer live mainly in the present. To act in the present, we must move back and forth between an imagined past and multiple imagined futures, thereby increasing the two-way interaction between thought and action. …
New abilities of researchers:
By measuring the degree of decay in linkage disequilibrium at a gene, they could estimate the length of time since a mutation or a selective sweep. …
Hawks et al. (2007) – humans over the past 40,000 years:
Almost 4 million SNPs were analyzed to estimate the rate of change to the human genome over the past 40,000 years.
Findings:
- Genetic evolution accelerated more than a hundredfold some 10,000 years ago, when hunting and gathering gave way to farming and other cultural changes (sedentary living, growth of towns and cities, rise of social complexity, etc.).
- This period of rapid evolution lasted well into the time of recorded history, peaking 8,000 years ago in Africa and 5,250 years ago in Europe. …
- This rapid evolution involved physiological adaptations to new diets or new diseases and, above all, cognitive adaptations to new ways of doing things. …
Kuijpers et al. (2022) – Europeans over the past ~35,000 years:
Evolution of cognitive ability was measured by alleles associated with intelligence, fluid intelligence, and educational attainment (EA).
Findings:
- No change in mean cognitive ability during the long period of hunting and gathering
- With the emergence of farming, a steady rise throughout the Neolithic and into historic times
- Stagnation during the classical era of civilization
- A steady rise over the last few centuries
Piffer et al. (2023) – Central Italians over the past 10,000 years:
Findings:
- A steady rise in mean cognitive ability through prehistory and into the time of the Roman Republic
- A sharp fall during the Imperial Era.
- A steady rise from Late Antiquity to early modern times …
- A fall beginning somewhere after 1800 and continuing to the present
Piffer & Connor (2025a) – An English region from the 11th to 19th centuries:
Findings:
- No clear change until the 1300s, followed by a steady rise in mean cognitive ability until the 19th century.
- On a per capita basis, the highly intelligent became ten times more numerous in England between 1000 and 1850, i.e., the top 1% in 1850 were as smart as the top 0.1% in the year 1000
What next?
We will soon see a study of cognitive evolution in South Asia. Its findings will probably resemble those of East Asia and the Roman world: a steady rise in mean cognitive ability, followed by decline. Cognitive evolution is usually driven by the higher fertility of elite individuals, and such people inevitably reach a level of development where the pursuit of wealth and power becomes severed from reproductive success.
Hopefully, we will see more studies of European cognitive evolution, particularly for the key period of the past millennium. During this period, mean cognitive ability rose steadily, perhaps beginning earlier in England, Holland, and northern Italy. By charting this advance by region and by century, we may learn more about the historical processes leading to the Reformation, the Enlightenment and the Industrial Revolution.
More, and details, at the link.