Degree of heterogeneity in the contexts of language users mediates the cognitive-communicative trade-off in semantic categorization

It has been argued that patterns of cross-linguistic variation in the semantic categories labelled by individual words are a result of a trade-off between cognitive pressures (so as to be simple to learn and use) and communicative pressures (so as to be efficient in communication). However, the question of what exact mechanisms control this trade-off has been left largely unanswered. We argue that one factor could be the extent to which referential contexts at the level of local interactions are similar or different across users of a category system. To test this hypothesis we propose a hierarchical Bayesian model for communication in a multidimensional meaning space, in which agents actively consider spatial similarity relations during interaction. Our models predict that less variability in contexts across interactions induces categories with lower communicative cost, while more variable contexts across partners are more strongly associated with category systems with lower cognitive cost.