Changes in post-marital residence precede changes In descent systems in Austronesian societies

Descent systems express how a society organises kinship relationships. Inheritance of
resources as well as rights and obligations can be traced patrilineally, matrilineally, a
combination of both, or in a cognatic/bilateral fashion. Post-marital residence rules describing the kin group with whom a couple lives after marriage are often, but not always, correlated with the descent system. Murdock (1949) hypothesised that changes in the residence system would cause changes in descent, not the other way around. Here we present a Bayesian phylogenetic analysis of 67 Austronesian societies from the Pacific. These comparative methods take into account uncertainty about the phylogeny as well as uncertainty about the evolution of the cultural traits. Ancestral state reconstruction shows that unilineal residence and non-unilineal descent are the ancestral states for this group of societies. Descent changes lag behind residence changes over a 1000-year time period. Environmental or cultural change (both frequent in Austronesian prehistory) may be facultatively adjusted to via the residence system in the short term, and thus this trait may change more often.