Infinite Mixture Chaining: An Efficiency-Based Framework for the Dynamic Construction of Word Meaning.

The lexicon is an evolving symbolic system that expresses an unbounded set of emerging meanings with a limited vocabulary. As a result, words often extend to new meanings. Decades of research have suggested that word meaning extension is non-arbitrary, and recent work formalizes this process as cognitive models of semantic chaining whereby emerging meanings link to existing ones that are semantically close. Existing approaches have typically focused on a dichotomous formulation of chaining, couched in the exemplar or prototype theories of categorization. However, these accounts yield either memory-intensive or simplistic representations of meaning, while evidence for them is mixed. We propose a unified probabilistic framework, infinite mixture chaining, that derives different forms of chaining through the lens of cognitive efficiency. This framework subsumes the existing chaining models as a trade-off between representational accuracy and memory complexity, and it contributes a flexible class of models that supports the dynamic construction of word meaning by automatically forming semantic clusters informed by existing and novel usages. We demonstrate the effectiveness of this framework in reconstructing the historical development of the lexicon across multiple word classes and in different languages, and we also show that it correlates with human judgment of semantic change. Our study offers an efficiency-based view on the cognitive mechanisms of word meaning extension in the evolution of the lexicon.