Young children’s understanding of communication as causal influence

A causal, mentalistic understanding of communication—a process by whicha speaker’s mind causes a change in a listener’s mind—can support powerfulinferences that go beyond observable data. For example, if A struggles toactivate a toy but succeeds after B whispers to A, you can infer that B knewhow to activate it even without hearing what was said. Although humans areprecocious communicators, much remains unknown about how we develop anabstract understanding of communication that enables rich inferences aboutother minds. The current work examined young children’s ability to rea-son about speakers’ knowledge based on their causal influence over listeners.Children viewed two scenarios where a listener failed to activate a toy twicebefore finally succeeding, and a speaker spoke to the listener in a nonsenselanguage. When one speaker communicated before a listener’s success whilethe other communicated before a listener’s failure, even 3-year-olds chose theformer speaker as the one who knew how the toy works (Exp.1). However,when communication always preceded success but the scenarios differed inwhat would’ve happened without communication—the listener was eitherpoised to fail again or succeed on their own—a clear preference for the for-mer speaker did not emerge until around age 7 (Exps.2&3). Importantly,across all experiments, children held no preference when speakers producednon-speech vocalizations. These results suggest young children already havean abstract understanding of communication as a causal, mentalistic process,but their inferences are constrained by the causal cues available in context.