Proceedings of the Annual Meeting of the Cognitive Science Society

Across languages, adjectives are subject to ordering restric-tions. Recent research shows that these are predicted by ad-jective subjectivity, but the question remains open why this isthe case. We first conduct a corpus study and not only replicatethe subjectivity effect, but also find a previously undocumentedeffect of mutual information between adjectives and nouns.We then describe a rational model of adjective use in whichlisteners explicitly reason about judgments made by differentspeakers, formalizing the notion of subjectivity as agreementbetween speakers. We show that, once incremental process-ing is combined with memory limitations, our model predictseffects both of subjectivity and mutual information. We con-firm the adequacy of our model by evaluating it on corpus data,finding that it correctly predicts ordering in unseen data withan accuracy of 96.2 %. This suggests that adjective orderingcan be explained by general principles of human communica-tion and language processing.