Human attention is limited in its capacity and duration. In language, this is manifested in many ways, but more conspicuously in the strategies by which information is distributed in utterances, that is, their information structures. We contend that the pragmatic categories of Topic and Presupposition precisely meet the necessity to modulate attentional resources on sentence contents, and they do this by “directing” certain contents to automatic and others to controlled processing mechanisms. We discuss experimental findings suggesting that presupposed or topicalized (...) information correlates with automatic processing, and we suggest that this association grounded for the emergence of topic and presupposition units in human communication. We also put forth the processing automaticity induced by these units as the rationale behind their persuasiveness in some specific contexts of language use. (shrink)