Young children's understanding of justifications for breaking a promise

There are sometimes legitimate reasons for breaking a promise when circumstances change. We investigated 3- and 5-year-old German children's understanding of promise breaking in prosocial (helping someone else) and selfish (playing with someone else) conditions. In Study 1 (n = 80, 50% girls), preschoolers initially kept their own promise in all conditions. When they eventually broke their promise, 3-year-olds’ justifications mostly referenced salient events, whereas 5-year-olds also referenced social norms. In Study 2 (n = 65, 49% girls), 5-year-olds preferred others’ promise-breaking more in prosocial than selfish conditions; 3-year-olds showed the reverse pattern. Three-year-olds’ justifications focused on desires, whereas 5-year-olds focused on relevant events. Overall, 3-year-olds were able to offer justifications, but 5-year-olds started to distinguish what counted in the eyes of others as “good” and “bad” reasons for promise breaking.