Matthews, L. J., Tehrani, J. J., Jordan, F., Collard, M., & Nunn, C. (2011). Testing for divergent transmission histories among cultural characters: A study using Bayesian phylogenetic methods and Iranian tribal textile data. Plos One,6(4), e14810. doi:10.1371/journal.pone.0014810.
Background: Archaeologists and anthropologists have long recognized that different cultural complexes may have distinct
descent histories, but they have lacked analytical techniques capable of easily identifying such incongruence. Here, we
show how Bayesian phylogenetic analysis can be used to identify incongruent cultural histories. We employ the approach to
investigate Iranian tribal textile traditions.
Methods: We used Bayes factor comparisons in a phylogenetic framework to test two models of cultural evolution: the
hierarchically integrated system hypothesis and the multiple coherent units hypothesis. In the hierarchically integrated
system hypothesis, a core tradition of characters evolves through descent with modification and characters peripheral to
the core are exchanged among contemporaneous populations. In the multiple coherent units hypothesis, a core tradition
does not exist. Rather, there are several cultural units consisting of sets of characters that have different histories of descent.
Results: For the Iranian textiles, the Bayesian phylogenetic analyses supported the multiple coherent units hypothesis over
the hierarchically integrated system hypothesis. Our analyses suggest that pile-weave designs represent a distinct cultural
unit that has a different phylogenetic history compared to other textile characters.
Conclusions: The results from the Iranian textiles are consistent with the available ethnographic evidence, which suggests
that the commercial rug market has influenced pile-rug designs but not the techniques or designs incorporated in the other
textiles produced by the tribes. We anticipate that Bayesian phylogenetic tests for inferring cultural units will be of great
value for researchers interested in studying the evolution of cultural traits including language, behavior, and material