Reasoning about knowledge: Children's evaluations of generality and verifiability.

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.

Can't stop believing: inhibitory control and resistance to misleading testimony.

Why are some young children consistently willing to believe what they are told even when it conflicts with first-hand experience? In this study, we investigated the possibility that this deference reflects an inability to inhibit a prepotent response. Over the course of several trials, 2.5- to 3.5-year-olds (N = 58) heard an adult contradict their report of a simple event they had both witnessed, and children were asked to resolve this discrepancy. Those who repeatedly deferred to the adult's misleading testimony had more difficulty on an inhibitory control task involving spatial conflict than those who responded more skeptically. These results suggest that responding skeptically to testimony that conflicts with first-hand experience may be challenging for some young children because it requires inhibiting a normally appropriate bias to believe testimony.

Young children have a specific, highly robust bias to trust testimony.

Why are young children so willing to believe what they are told? In two studies, we investigated whether it is because of a general, undifferentiated trust in other people or a more specific bias to trust testimony. In Study 1, 3-year-olds either heard an experimenter claim that a sticker was in one location when it was actually in another or saw her place an arrow on the empty location. All children searched in the wrong location initially, but those who heard the deceptive testimony continued to be misled, whereas those who saw her mark the incorrect location with an arrow quickly learned to search in the opposite location. In Study 2, children who could both see and hear a deceptive speaker were more likely to be misled than those who could only hear her. Three-year-olds have a specific, highly robust bias to trust what people--particularly visible speakers--say.