Children's moral judgments of commission and omission based on their understanding of second-order mental states

Children's moral judgments about acts of commission and omission with negative outcomes were studied based on their understanding of mental states. Children (N = 142) in the first, third, and fifth grades made judgments about four tasks composed of two levels of mental states (first-order or second-order) and two types of acts (commission or omission). The results showed that the 7-year-olds responded considering only first-order mental states, but the 9- and 11-year-olds also used second-order mental states in their judgments. Whether the acts were commission or omission did not make a difference. These results indicate that children can make moral judgments regarding acts of commission and omission based on an understanding of second-order mental states by approximately the age of 9 years.