Anticipating disagreement enhances source memory in English- and Turkish-speaking preschool children

Metacognitive abilities like source memory are useful for justifying our beliefs to others. Do they arise because of this need? Here, we test whether circumstances that require source reporting enhance source memory. We test this in circumstances in which children anticipate a disagreement, and when children speak a language with obligatory linguistic evidential marking of source (Turkish). We asked 160 English- and Turkish-speaking 3- and 4-year-olds to recall how they knew something and what they knew when communicating with an agreeing or disagreeing interlocutor. Four-year-old English speakers and 3- and 4-year-old Turkish speakers correctly recalled first-hand sources (seeing the object themselves) better than second-hand sources (hearing about it from the experimenter) when they expected their interlocutor to disagree. Disagreement did not affect memory for perceptual features, suggesting its influence is specific to source memory. Together, these results highlight the importance of social and linguistic influences on metacognition, though with some important qualifications about the types of sources relevant for justifying one’s beliefs.