How do children decide when to believe a claim? Here we show that children fact-check claims more and are better able to catch misinformation when they have been exposed to detectable inaccuracies. In two experiments (N = 122), 4–7-year-old children exposed to falsity (as opposed to all true information) sampled more evidence before verifying a test claim in a novel domain. Children’s evidentiary standards were graded: fact-checking increased with higher proportions of false statements heard during exposure. A simulation suggests that children’s behaviour is adaptive, because increased fact-checking in more dubious environments supports the discovery of potential misinformation. Importantly, children were least diligent at fact-checking a new claim when all prior information was true, suggesting that sanitizing children’s informational environments may inadvertently dampen their natural scepticism. Instead, these findings support the counterintuitive possibility that exposing children to some nonsense may scaffold vigilance towards more subtle misinformation in the future.

孩子们如何决定何时相信一个说法？在这里，我们表明，当儿童接触到可检测的不准确信息时，他们会更多地对声明进行事实核查，并且能够更好地捕捉错误信息。在两个实验 （N = 122） 中，暴露于虚假信息（而不是所有真实信息）的 4-7 岁儿童在验证新领域的测试声明之前抽样了更多证据。对儿童证据标准进行分级：事实核查增加，在暴露期间听到的虚假陈述比例更高。模拟表明儿童的行为是适应性的，因为在更可疑的环境中增加事实核查有助于发现潜在的错误信息。重要的是，当所有先前的信息都是真实的时，孩子们最不勤于对新的说法进行事实核查，这表明净化儿童的信息环境可能会无意中抑制他们天生的怀疑。相反，这些发现支持了一种违反直觉的可能性，即让孩子接触一些无稽之谈可能会使他们对未来更微妙的错误信息保持警惕。