The challenge of tree-thinking and network-thinking: conceptual issues across biological and cultural domains

This talk gives a reflexive outlook on the employment of tree and network thinking to conceptualize and model vertical descent and horizontal transmission of cultural traits. In biology, evolutionary trees are more than tools for researchers across disciplines: they are the main framework within which evidence for evolution is evaluated (Baum et al. 2005). However, several biologists have recognized "tree thinking" as a challenge for students (Gregory 2008, Meisel 2010), lay people (Baum, cit.), and scientists alike (O'Hara 1992), going against our spontaneous cognitive tendencies, e.g., reading along the tips, locating evolution only at nodes, projecting living species backwards to internal nodes. Moreover, common descent, represented by trees, is not the only way in which biological traits are shared: the ubiquity of phenomena like lateral gene transfer is increasing the need for network-based analyses, introducing the conceptual challenge of "network thinking" (Proulx et al. 2005), and the further complexity of conceiving trees and networks together. I focus on which strategies, used and developed in biology, can be implemented in anthropology to address cultural relatedness and common ancestry relationships. Baum DA et al. (2005). The tree-thinking challenge. Science 310(5750):979-980. Gregory TR (2008). Understanding evolutionary trees. Evolution: Education and Outreach 1(2):121-137. Meisel RP (2010). Teaching tree-thinking to undergraduate biology students. Evolution: Education and Outreach 3(4):621-628. O'Hara RJ (1992). Telling the tree: Narrative representation and the study of evolutionary history. Biology and Philosophy 7(2):p.135–160. Proulx SR et al. (2005). Network thinking in ecology and evolution. Trends in Ecology and Evolution 20(6):345-53.