My most exciting discovery during my first year back in school was part of my research for a paper. I had planned on incorporating meme theory into an approach to explaining how beliefs become tradition. Fortunately, my professor pointed me to an article about cultural evolution, which turned me off from memes and turned me onto co-evolution. With excitement, I read about this emerging branch of evolutionary theory (for an introduction, please see the SEP entry). I abandoned that research during the semester when it became clear that my paper idea was way too ambitious. Now that the semester is done (and the paper on belief packages complete), I can return to the theory that underlies co-evolutionary thinking: Developmental systems theory. I’ve already mentioned it briefly but want to share a little more here.

Developmental systems theory (DST) is an approach that does not answer the nature/nurture dichotomy. It overcomes it by suggesting that not only are both important as causal factors but that there is interaction between nature and nurture that make it impossible to look at each factor separately. Only a systems approach that integrates can truly explain the various influences. Note that this approach is no longer linear, as the approaches of EP are, for example, which give most weight to nature/genes with a dash of nurture. DST captures interaction: Genes impact the environment which impacts genes which impact the environment and so on. For an article that sketches how this might work, please check out Anne Fausto-Sterling’s “Bare Bones” articles (a PDF to Part I is here). She only gives a very broad overview of DST itself but the article is really DST in action, which might be a very good way of being introduced to a theoretical approach that requires a paradigm shift in our thinking.

The best introduction to DST is a book edited by Susan Oyama (who, I believe, is the researcher who introduced DST to biology), Paul Griffiths, and Russell Gray: Cycles of Contingency. Here are the major themes of DST as presented in Table 1.1 of that book:

1. Joint determination by multiple causes – every trait is produced by the interaction of many developmental resources. The gene/environment dichotomy is only one of many ways to divide up these interactants.
2. Context sensitivity and contingency – the significance of any one cause is contingent upon the state of the rest of the system.
3. Extended inheritance – an organism inherits a wide range of resources that interact to construct that organism’s life cycle.
4. Development as construction – neither traits nor representations of traits are transmitted to offspring. Instead, traits are made – reconstructed – in development.
5. Distributed control – no one type of interactant controls development.
6. Evolution as construction – evolution is not a matter of organisms or populations being molded by their environments, but of organism-environment systems changing over time.

Sounds complicated? Well, it is more complicated than the “genes (with a dash of nurture) are behind {insert your favorite trait}” approach. But so are organisms.