The Evolutionary Dynamics of Negative Existentials in Indo-European

Where in earlier work diachronic change is used to explain away exceptions to typologies, linguistic typologists have started to make use of explicit diachronic models as explanations for typological distributions. A topic that lends itself for this approach especially well is that of negation. In this article, we assess the explanatory value of a specific hypothesis, the Negative Existential Cycle (NEC), on the distribution of negative existential strategies (“types”) in 106 Indo-European languages. We use Bayesian phylogenetic comparative methods to infer posterior distributions of transition rates and parameters, thus applying rational methods to construct and evaluate a set of different models under which the attested typological distribution could have evolved. We find that the frequency of diachronic processes that affect negative existentials outside of the NEC cannot be ignored—the unidirectional NEC alone cannot explain the evolution of negative existential strategies in our sample. We show that non-unidirectional evolutionary models, especially those that allow for different and multiple transitions between strategies, provide better fit. In addition, the phylogenetic modeling is impacted by the expected skewed distribution of negative existential strategies in our sample, pointing out the need for densely sampled and family-based typological research.

Evolutionary dynamics of Indo-European alignment patterns

This paper employs phylogenetic modeling to reconstruct the alignment system of Indo-European. We use a data set of categorical morphosyntactic features, which take states such as ‘nominative-accusative’, ‘active-stative’, or ‘ergative’. We analyze these characters with a standard Bayesian comparative phylogenetic method, inferring transition rates between character states on the basis of a phylogenetic representation of the languages in the data. Using these rates, we then reconstruct the probability of presence of traits at the root and nodes of Indo-European. We find that the most probable alignment system for Proto-Indo-European is a nominative-accusative system, with low probabilities of neutral marking and ergativity in the categories lower in grammatical hierarchies (nouns, past). Using a test of phylogenetic signal, we find that characters pertaining to categories higher in hierarchies show greater phylogenetic stability than categories lower in hierarchies. We examine our results in relation to theories of Proto-Indo-European alignment as well as to general typology.

Cultural macroevolution matters

Evolutionary thinking can be applied to both cultural microevolution and macroevolution. However, much of the current literature focuses on cultural microevolution. In this article, we argue that the growing availability of large cross-cultural datasets facilitates the use of computational methods derived from evolutionary biology to answer broad-scale questions about the major transitions in human social organization. Biological methods can be extended to human cultural evolution. We illustrate this argument with examples drawn from our recent work on the roles of Big Gods and ritual human sacrifice in the evolution of large, stratified societies. These analyses show that, although the presence of Big Gods is correlated with the evolution of political complexity, in Austronesian cultures at least, they do not play a causal role in ratcheting up political complexity. In contrast, ritual human sacrifice does play a causal role in promoting and sustaining the evolution of stratified societies by maintaining and legitimizing the power of elites. We briefly discuss some common objections to the application of phylogenetic modeling to cultural evolution and argue that the use of these methods does not require a commitment to either gene-like cultural inheritance or to the view that cultures are like vertebrate species. We conclude that the careful application of these methods can substantially enhance the prospects of an evolutionary science of human history.