Young children use conversational timing as a cue for prosocial commitment.

Turn-taking in conversation entails periods of silence between talkers. Adults use the duration of these inter-turn intervals (ITIs) to draw inferences about the speaker. This study explores the emergence of these abilities in young children (104 Chinese children, 41-77 months, 44 female, 2025). Children watched cartoon vignettes in which a cartoon character requested help from two friends whose respective responses followed either a short (600 ms) or long (4,000 ms) delay. Children then judged the responders' willingness to help and stated which character they preferred. As age increased, children were more likely to judge slow responders as less willing and less preferable, (OR = 1.86-1.99), reaching above-chance levels around 51 months for willingness to help (OR = 2.12) and 53 months for friend preference (OR = 1.92). Interestingly, all children could distinguish fast from slow responses on an independent ITI discrimination task (OR = 11.14), suggesting younger children readily perceived timing differences but were unable to incorporate them into social inferences. Further, ITI-based inferences were unrelated to rhythmic ability but were predicted by Theory of Mind performance. These findings benchmark children's sensitivities to conversational timing in early social cognitive development, highlighting the role of emerging Theory of Mind abilities.