Competing motivations and emergence: explaining implicational hierarchies

It is the basic tenet of the functional approach to typology that at least some linguistic universals may be explained by appealing to features of language use. But the mechanics of the mapping between function and distribution are seldom made explicit. In this paper, a theory of linguistic adaptation is set out in which universals are treated as phenomena of the third kind in Keller’s (1994) terms, i.e. objects which are the result of human actions but not the goal of their intentions. In this view universals emerge at a global level from the interactions of individuals whose actions locally can be described in terms of functional motivations. Computational models of this process (an invisible hand process) can be set up to see what universals emerge with different functional pressures in place. Using this model, Keenan and Comrie’s accessibility hierarchy is shown to emerge when competing functional pressures relating to structural complexity and morphological complexity are taken into account. This is contrasted with claims that structural complexity asymmetries alone can explain implicational universals. The value of this approach is further demonstrated by testing the predicted skewing in the distribution of ‘case-coding’ strategies down the hierarchy.