revious studies investigated infants’ ability to recognize turn-taking exchanges of signals that can serve communicative information transfer and draw pragmatic inferences from them. Here we investigate 13-month-olds’ expectations about the distal effects of communicative versus non-communicative actions and explore their understanding of the epistemic causal mechanisms through which communicative signals modify their addressees’ consequent intentional actions. In four looking time experiments (Ntotal = 80), we found that infants understand that communicative signals cannot bring about non-intentional state changes in other entities and expect their distal effects to be limited to inducing intentional behavioral reactions in recipient agents. These results indicate that human infants possess cognitive mechanisms to understand the unique causal affordances of ostensive communicative actions. Coupled with their evolved pragmatic inferential capacities and communicative mindreading skills, these abilities form a specialized cognitive system for interpreting ostensive communicative information exchange between communicating social partners.