Hopefully a long hiatus is behind me, and I’ll be posting more regularly about research topics and scientific issues. I spent much of the last academic year on conference papers, a dissertation proposal, and getting myself positioned for general exams this year. With that accomplished, and my dissertation research solidified and underway, I feel better able to post on my research in more detail.
In general, my topic concerns the “renormalization” of cultural transmission models. This terminology will probably be unfamiliar to anthropologists and social scientists, so I’m not going to emphasize the term or formal renormalization theory in upcoming publications or my dissertation, but it is absolutely what I’m studying. I thought a blog post would be a good place to describe this concept, and its relationship to concepts more familiar to anthropologists.
Those who study long-term records of behavior or evolution face the problem that evolutionary models are individual-based or “microevolutionary,” and describe the detailed change in adoption of traits or flow of genetic information within a population, while our empirical data describe highly aggregated, temporally averaged counts or frequencies. This mismatch in temporal scales is extreme enough that the “evolutionary synthesis” of the 1940′s tended to separate consideration of “microevolution” and “macroevolution” into different sets of processes (largely as a result of George Gaylord Simpson’s pioneering work). The study of the fossil record of life on earth has rightly focused mainly on the phylogenetic history of species and higher taxa, in their paleoecological contexts. When studying the archaeological record of human behavior over shorter (albeit still substantial) time scales, it seems less clear that microevolutionary models cannot inform our explanations.
At the same time, our usage of microevolutionary models of cultural transmission, to date, has almost universally ignored the vast difference in time scales between our evidence and the behavioral events and “system states” we model. The sole exception to this rule, actually, seems to be Fraser Neiman’s 1990 dissertation, which has a sophisticated discussion of the effects of time-averaging on neutral models and cultural trait frequencies. So, an important question would be: what do cultural transmission models look like, when we view their behavior through the lens of a much longer-term data source?
This is precisely the kind of question that renormalization theory answers, as formulated in physics. Below the jump, I describe renormalization in more detail.