The language children hear presents them with a multitude of co-occurrences between words and things in the world, and they must repeatedly determine which among these manifold co-occurrences is relevant. Social factors--such as cues regarding the speaker's referential intent--might serve as one guide to whether word-object covariation should be registered. In 2 studies, infants (15-20 months and 18-20 months in Studies 1 and 2, respectively) heard novel labels at a time when they were investigating a single novel object; in one case the label was uttered by a speaker seated within the infant's view and displaying concurrent attention to the novel toy (coupled condition), whereas in the other case the label emanated from a speaker seated out of the infant's view (decoupled condition). In both studies, subsequent comprehension questions indicated that infants of 18-20 months registered a stable link between label and object in the coupled conditions, but not in the decoupled condition, despite the fact that covariation between label and object was equivalent in the 2 conditions. Thus, by 18-20 months children are inclined to establish a mapping between word and object only when a speaker displays signs of referring to that object.