Infants differentiate between successful and failed communication in a false-belief context

Communication is based on social interaction, that is, interlocutors sharing attention to the intentions that they communicate about. In this study, we asked whether infants are aware of the fact that for information to be transferred, both interlocutors need to be present and share attention. Using a violation-of-expectation paradigm created to test infants' understanding of others' false beliefs, we asked whether 18-month-olds (n = 84) understood that correcting an agent's false belief via communication requires that the agent discerns the verbal statement. Participants saw how an agent put a toy into a box and left. An assistant then moved the toy into a cup. The intervention phase varied between three conditions: The agent and the assistant communicated about the actual location of the toy (full-communication), the agent was absent during the assistant's statement (incomplete-communication) or no communication took place (no-communication). At test, the agent reached into either the box or the cup. When no communication took place, infants expected the agent to search the toy at the original location. Full communication resulted in infants' expectations that the recipient's actions were altered, that is, the infants expected her to search the toy at the actual location. In contrast, incomplete communication did not yield clear expectations. Eighteen-month-olds thus seem to understand that for information to be transferred, it is a precondition that the recipient of the communicative act must be present and share attention during the communicator's statement. Only then communication can change a recipient's mental state.