Omission bias in children's and adults' moral judgments of lies.

This study examined whether omission bias occurs in moral judgments of lies. Omission bias is the tendency to judge acts of commission as morally worse than equivalent acts of omission. Children aged 8 and 9 years (third graders) and 11 and 12 years (sixth graders), as well as adults, made moral judgments about lies of commission and omission to conceal transgressions. Descriptions of four scenarios varied in terms of whether the protagonists lied to benefit themselves or others and whether the transgression was deliberate or accidental. The results showed that both age groups of children, as well as adults, judged that lies of commission were morally worse than lies of omission in all four scenarios, indicating that omission bias clearly occurs in moral judgments of lies. However, there were age differences in the magnitude of omission bias. Third and sixth graders generally showed omission bias of the same magnitude for all scenarios, whereas omission bias in adults was stronger for the scenarios that benefited self rather than others and for scenarios in which deliberate transgressions, rather than accidental ones, were concealed. These results reveal differences in moral judgments of lies between middle childhood and adulthood.