According to an orthodox view, co-referential expressions like “Hesperus” and “Phosphorus” are associated with different modes of presentation. This explains why a competent and rational speaker who finds the sentence “Hesperus is Hesperus” trivial can find the sentence “Hesperus is Phosphorus” informative. This paper introduces a pragmatist account based on the notion of identification abilities. Instead of explaining differences in cognitive value in semantic terms, I propose to account for them by means of psychological principles that govern identification. I call these principles “constraints,” and show that they differ from traditional modes of presentation in various ways. To this end, I show how perceptual tracking is governed by constraints, and how it is enhanced by the use of the shape of words as a ‘proxy’ of sameness and difference in reference.