Does Ancient DNA Track Archaeological Change?

Europe did not enter the Iron Age all at once. Different societies adopted farming, metalworking and other technologies at different times. Two communities living in the same century could therefore belong to different archaeological periods.

That unevenness was central to Does Ancient DNA Track Human Progress, or Just Time?. The question was whether genetic scores linked to education were associated with how far a society had moved through the archaeological sequence. Different societies reached farming, metalworking and later technologies at different times. Around 650 BCE, for example, one burial in Latvia is classified as Late Bronze Age while another in Italy is classified as Iron Age. Did genetic scores differ between societies that had reached different stages at roughly the same time? That is a more demanding test than simply comparing older populations with more recent ones.

There is a human question behind the statistical one. Farming requires people to plan around delayed returns. Metalworking depends on skills that must be learned, remembered and transmitted. More elaborate societies bring new demands on coordination and accumulated knowledge. It is reasonable to ask whether traits associated with reasoning, learning and future orientation played a part in those changes. Ancient DNA gives us a way to investigate that question, although genetic scores measured in modern populations remain an indirect guide to people who lived thousands of years ago.

The evidence has now improved in a fairly literal way. I went back to the papers and their supplementary files, looking for the archaeological descriptions behind the genetic records. That expanded the source-supported European sample well beyond the initial 1,730 records. It also exposed a problem with counting skeletons: a cemetery with a hundred sequenced burials may still supply only one archaeological phase.

I grouped individuals by site and by the archaeological phase identified in the original study, then treat each group as one observation.. I also used newer genetic scores for fluid intelligence, alongside educational attainment and delay discounting. That makes the comparison more interesting, because education, reasoning ability and willingness to wait are related ideas without being interchangeable measurements.

The intelligence result remains worth pursuing. But the latest checks change the explanation of why some models looked stronger than others. The new results suggest that intelligence-linked genetic scores capture something beyond the passage of time. How much survives closer scrutiny?

One burial is classified as Late Bronze Age, another as Iron Age. Both have a recorded date estimate of 650 BCE (Figure 1). Can ancient DNA tell us anything about that difference once the calendar is held constant?

Figure 1. Two individuals at the same recorded date in different archaeological periods

Upgrade to explore the larger source-study dataset, compare intelligence, education and patience in the new effect plots, and follow what happens when I average within archaeological phases and allow the relationship between date and archaeological period to follow a smooth curve.