How do we know what others know? Prior work has focused on our early-emerging ability to infer the knowledge of single agents. Yet we often infer others’ knowledge by observing interactions between agents. In particular, the ability to reason about what communicators know can help children identify knowledgeable teachers. The present study investigates whether preschool-aged children infer what communicators know from how their communication influences listeners. Children observed two scenarios where a listener failed to activate a toy before succeeding. In the Effective-Communicator scenario, a speaker spoke nonsense language to a listener after they failed but before they succeeded. In the Ineffective- Communicator scenario, a speaker spoke to a listener before they initially failed. By around age 5, children preferred the one in the Effective- Communicator scenario when asked which speaker knows how the toy works. These results suggest young children can infer communicators’ knowledge solely from the presence of communication and its influence on others.

Humans have an intuitive sense of what others know and how they learned it. These expectations are often latent, but violating them can elicit surprise and curiosity (e.g., a stranger knowing a lot about you). Here we investigate the development of epistemic expectations by measuring young children's sensitivity to such violations. First, parents reported that children typically respond to violations of epistemic expectations by age 4 (Exp.1). In naturalistic dialogue experiments with 4- and 5-year-olds, children were more likely to display surprised expressions and report being surprised when the experimenter’s parent knew personal information about them than when their own parent did (Exp.2). However, children showed an opposite pattern when these people knew information about the experimenter’s sibling (Exp.3). Together, these results suggest preschool-aged children are sensitive to others' access to information and readily detect violations of their epistemic expectations in casual conversation.

Prior work demonstrates an early-emerging understanding of how speakers can alter listeners’ minds and actions. Yet, an abstract understanding of communication entails more than forward inferences about its influence on the listener; it also supports inverse inferences about the speaker based on its causal influence over the listener. Can children reason about the minds of speakers based on their causal influence over listeners? Across three studies, children viewed two communicative exchanges where a listener attempted to activate a toy; we manipulated when speakers communicated (Exp.1), how listeners’ subsequent actions changed (Exp.2), and whether speakers spoke or sneezed (Exp.3). By 5 years of age, children inferred the speaker who appeared to cause the listener to succeed was more knowledgeable, but only when they produced speech. These results suggest children can reason causally about the sources of communication, identifying knowledgeable speakers based on their influence over a listener’s actions and their outcomes.

Information from the news undoubtedly shapes what we believe is true, but we argue the language it employs also influences whether we think an assertion has a ground truth at all. Six studies examined how epistemic language in particular influences adults’ inferences of objectivity and truth. When headlines about novel topics (Studies 1a-b) or climate change (Studies 3a-b) presented information as belief (e.g., “Tortoise breeders believe tortoises are becoming more popular pets”), adults rated that information as less objective and less likely to be true compared to information presented as knowledge (e.g., “Tortoise breeders know [...]”). Epistemic language even influenced participants’ objectivity judgments when it had no influence on their truth judgments (Studies 2a-b). Overall, these results show the way epistemic language frames information affects what we perceive as true and, more so, whether we believe an objective truth exists in the first place.

Abstract: When inferring the extent of others’ knowledgefrom samples of what they know, certain kinds of samplesimply richer content. One candidate kind is knowledge ofcausal mechanism. In the current study, we investigatewhether children and adults think that knowledge aboutmechanism generalizes more broadly than non-mechanisticfactual knowledge. We find an early-emerging assumptionthat mechanistic knowledge about a basic level categoryimplies greater knowledge about a superordinate category,compared to factual knowledge about the same basic levelcategory. Even young children have a sophisticated sense ofhow causal mechanisms generalize across categories, despitepossessing little mechanistic knowledge themselves. Theseintuitions likely support the epistemic inferences we makefrom early childhood onward.

Prior work suggests children understand how speech conveys information and influences others’ minds. Although these studies have focused on communication under ideal conditions, auditory noise plagues the real world, often corrupting the transmission of information. The current study examines how children reason about the impact of auditory noise on communication. Children (N=72, Age:3;0-5;11) watched scenarios where a teacher tells a learner about two toys, but loud auditory noise masks one of the explanations. When asked which toy the learner wants to hear about again, children were more likely to select the noise-masked toy when the learner knew about neither toy (No Knowledge) than when he already knew about the masked toy (Partial Knowledge). However, their preference for the masked toy also increased with age in both conditions. Overall, these results demonstrate children's developing understanding of when and how communication affects listeners' knowledge and information-seeking behaviors.

Mechanistic information can be characterized as theinteracting causal components underlying a phenomenon - inshort, how something works. Children and adults arenotoriously poor at learning, remembering, and applyingmechanistic information, so it comes as no surprise that thewisdom of teaching mechanism has come under increasingscrutiny in science education. However, while a rich memoryfor mechanistic details may be out of the average student’sgrasp, we argue that exposure to mechanism does not leavestudents empty-handed. Instead, it refines their intuitionsabout science and the world in significant ways. For thecurrent study, we focused on one kind of intuition inparticular: beliefs about causal complexity. Children ages 6-11 rated the complexity of a heart and a lock and were thengiven either mechanistic or non-mechanistic informationabout them. Afterwards, they were asked if their intuitionsabout complexity had changed and if so by how much. Threeweeks later, children were asked again about their intuitionsabout complexity. Crucially, children who were givenmechanistic information demonstrated a significantly greatershift in their assessments of complexity for both the heart anddoor lock compared to their counterparts who were givennon-mechanistic information. This contradicts the notion thatmechanism provides learners with few benefits while alsodemonstrating how mechanism can be a powerful force inshaping children’s intuitions.

Adults routinely tailor their communication to others' auditory access, such as substituting gestures for speech in noisy environments. Yet, assessing the effectiveness of different communicative acts given others' perceptual access—especially when it differs from one's own—requires mental-state reasoning, which undergoes significant developmental change. Can young children tailor their communication to others' auditory access? In Study 1, parental report (n=98) indicated that most children, by age 4, adjust their communicative behaviors in noisy settings. Study 2 elicited these behaviors experimentally with 4- to 5-year-olds (n=68). Children taught how a novel toy works to a learner who wore headphones playing either loud music or nothing. Children were more likely to use physical demonstrations, and less likely to use verbal explanations, when the learner's auditory access was obstructed. These findings illustrate how mental-state reasoning might support children's ability to communicate successfully across perceptually-compromised contexts and individuals.