Children's understanding of physical possibility constrains their belief in Santa Claus

What role does children's understanding of physical possibility play in their acceptance of adults’ testimony about Santa? This question was addressed by comparing children's ability to differentiate events that do and do not violate physical laws to their skepticism toward Santa. Children aged 3–9 (n = 47) were asked (a) to generate information-seeking questions for Santa in a letter-writing task, (b) to explain how Santa accomplishes some of the feats he is purported to accomplish, and (c) to assess the possibility of various physically extraordinary events (unrelated to Santa), some possible and some impossible. Children who were better at differentiating possible events from impossible events had also begun to engage with the mythology surrounding Santa at a conceptual level, questioning the feasibility of Santa's extraordinary activities while also positing provisional explanations for those activities in the absence of a known answer. These findings suggest that children's acceptance of testimony about Santa – and possibly other forms of counterintuitive testimony – depends not only on the testimony they receive but also on the child's own understanding of physical possibility.