Reasoning about knowledge: Children’s evaluations of generality and verifiability

•Verifiability and generality serve distinct epistemic functions across development.•The youngest children credited knowledge to verifiable speakers.•Older children and adults credited knowledge to generic speakers.•Value placed on each function relates to a learners' knowledge in that domain.

In a series of experiments, we examined 3- to 8-year-old children’s (N = 223) and adults’ (N = 32) use of two properties of testimony to estimate a speaker’s knowledge: generality and verifiability. Participants were presented with a “Generic speaker” who made a series of 4 general claims about “pangolins” (a novel animal kind), and a “Specific speaker” who made a series of 4 specific claims about “this pangolin” as an individual. To investigate the role of verifiability, we systematically varied whether the claim referred to a perceptually-obvious feature visible in a picture (e.g., “has a pointy nose”) or a non-evident feature that was not visible (e.g., “sleeps in a hollow tree”). Three main findings emerged: (1) young children showed a pronounced reliance on verifiability that decreased with age. Three-year-old children were especially prone to credit knowledge to speakers who made verifiable claims, whereas 7- to 8-year-olds and adults credited knowledge to generic speakers regardless of whether the claims were verifiable; (2) children’s attributions of knowledge to generic speakers was not detectable until age 5, and only when those claims were also verifiable; (3) children often generalized speakers’ knowledge outside of the pangolin domain, indicating a belief that a person’s knowledge about pangolins likely extends to new facts. Findings indicate that young children may be inclined to doubt speakers who make claims they cannot verify themselves, as well as a developmentally increasing appreciation for speakers who make general claims.