Turning believers into skeptics: 3-year-olds’ sensitivity to cues to speaker credibility. Journal of Cognition and Development, 8, 263-283. doi: 10.1080/15248370701446392

Under most circumstances, children (and adults) can safely assume that the testi-mony they hear is true. In two studies, we investigated whether 3-year-olds (N = 100) would continue to hold this assumption even if the person who provided the testi-mony behaved in an uncertain, ignorant, and/or distracted manner. In Study 1, chil-dren were less likely to trust that, for example, a key-like object was a spoon if the speaker indicated uncertainty about her testimony (e.g., “I think this is a spoon”) than if she simply labeled the object ostensively (e.g., “This is a spoon”). In Study 2, 3-year-olds were also more skeptical about a speaker’s testimony when she had ear-lier made an obvious naming error and seemed distracted, but not when she either made an error or seemed distracted. These results indicate that 3-year-olds can re-spond differently to the same testimony, depending on the speaker’s behavior. Successful communication is built on trust. If you tell me that you had eggs for breakfast this morning, I trust that you actually believe that you had eggs. Your be-lief may be wrong because, for example, you misremembered or you ate an artifi-cial food that looked and tasted like eggs. Nevertheless, I expect that you believe what you say, and your saying it will likely cause me to believe it as well. As Grice (1975) pointed out, listeners expect that speakers will attempt to be truthful. In fact, a number of thinkers have suggested that children and adults may, by default, assume that testimony is true (e.g., Coady, 1992; Gilbert, 1991; Reid, 1764/1997; Spinoza, 1677/1982). Because most testimony is true, such a default assumption would be adaptive because it would mean listeners did not have to laboriously eval-uate the veracity of everything they heard