Innovation in the Paleolithic: Or, Why Dead Cavemen Don’t Use Hammers

One of the more interesting questions in innovation studies has to with tool homogeneity and stasis in ancient societies.  It’s not that change didn’t happen, because it did — but it happened less frequently than expected. There was simply less variety, both through geography and time, than expected.

Why? A new paper summarizes some views on the subject:

A range of cognitively based explanations has been offered for the relative lack of novelty and change in Lower and Middle Paleolithic technologies. Innovation is considered to be a key source of change in human behavior and culture [11], [12] and some researchers argue that the apparent stability of Lower and Middle Paleolithic material culture is rooted ultimately in the inability to innovate on the part of the hominins that produced the artifacts [13]–[15]. An opposing position holds that these individuals actually resisted change. From this perspective, highly persistent cultural traditions reflect what is in essence an extreme form of biased cultural transmission (e.g., [16], [17], but see [18]).

Source: Premo LS, Kuhn SL. Modeling Effects of Local Extinctions on Culture Change and Diversity in the Paleolithic. Shennan S, ed. PLoS ONE. 2010;5(12):e15582.

Neither of those explanations are particularly satisfactory, as Premo & Kuhn point out. For starters, they rely on the unobservable, on people’s cognitive traits, but the explanations also dismiss the innovative capacity of Lower and Middle Paleolithic hominins, which flies in the face of evidence that innovation capacity was there, just not in these tools.

So, time for a new explanation. There is an emerging school of thought in innovation that ties together population size, growth and communication linkages, a school that is getting much more attention lately in light of research around the rise and fall of cities. We know that proximity matters, that flux matters, and that density matters with respect a society’s innovative prowess. With this in mind, the authors tested a model of micro drop-offs — local extinctions of failed hominin bands — in a larger and more stable meta-population to see if a reason for the conformity and limited innovativeness in Paleolithic society could have been population based. Was it because bands that might have shared best practices in tool innovation too often died out before they made shared widely?

We investigate whether the appearance of stability in early Paleolithic technologies could result from frequent extinctions of local subpopulations within a persistent metapopulation. A spatially explicit agent-based model was constructed to test the influence of local extinction rate on three general cultural patterns that archaeologists might observe in the material record: total diversity, differentiation among spatially defined groups, and the rate of cumulative change. The model shows that diversity, differentiation, and the rate of cumulative cultural change would be strongly affected by local extinction rates, in some cases mimicking the results of conformist cultural transmission.

Fascinating stuff. [-]