Do children know when people tell the truth but not the whole truth? Here we show that children accurately evaluate informants who omit information and adjust their exploratory behavior to compensate for under-informative pedagogy. Experiment 1 shows that given identical demonstrations of a toy, children (6-and 7-year-olds) rate an informant lower if the toy also had non-demonstrated functions. Experiment 2 shows that given identical demonstrations, six-yearolds explore a toy more broadly if the informant previously committed a sin of omission. These results suggest that children consider both accuracy and informativeness in evaluating others' credibility and adjust their exploratory behavior to compensate for under-informative testimony when an informant's credibility is in doubt.

Adults and children recruit a specific network of brain regions when engaged in "Theory of Mind" (ToM) reasoning. Recently, fMRI studies of adults have used multivariate analyses to provide a deeper characterization of responses in these regions. These analyses characterize representational distinctions within the social domain, rather than comparing responses across preferred (social) and non-preferred stimuli. Here, we conducted opportunistic multivariate analyses in two previously collected datasets (Experiment 1: n=20 5-11 year old children and n=37 adults; Experiment 2: n=76 neurotypical and n=29 5-12 year old children diagnosed with Autism Spectrum Disorder (ASD)) in order to characterize the structure of representations in the developing social brain, and in order to discover if this structure is disrupted in ASD. Children listened to stories that described characters' mental states (Mental), non-mentalistic social information (Social), and causal events in the environment (Physical), while undergoing fMRI. We measured the extent to which neural responses in ToM brain regions were organized according to two ToM-relevant models: 1) a condition model, which reflected the experimentergenerated condition labels, and 2) a data-driven emotion model, which organized stimuli according to their emotion content. We additionally constructed two control models based on linguistic and narrative features of the stories. In both experiments, the two ToM-relevant models outperformed the control models. The fit of the condition model increased with age in neurotypical children. Moreover, the fit of the condition model to neural response patterns was reduced in the RTPJ in children diagnosed with ASD. These results provide a first glimpse into the conceptual structure of information in ToM brain regions in childhood, and suggest that there are real, stable features that predict responses in these regions in children. Multivariate analyses are a promising approach for sensitively measuring conceptual and neural developmental change and individual differences in ToM.