UC Berkeley

The moral prohibition against harming others is fundamental to any social unit, including families with young children. Yet, infants appear less averse to harming others than do older children and adults. Infants' harmful actions may in turn elicit strong reactions from others that could contribute to the acquisition of morality.

The present study investigated two main propositions: 1) mothers respond differently to infants' harmful acts against others (moral transgressions) than when intervening on transgressions related to infants' own well-being (prudential transgressions) or the creation of inconvenience, such as spilling (pragmatic transgressions). 2) Most infants harm others even without provocation. Twenty-six infants and their families participated in a 2.5-hour naturalistic home observation when the infant was 14 months old. Most of the families participated in additional visits when the infant was 19 (N = 24) and 24 (N = 22) months of age.

All infants who participated in three visits had at least one instance of purposefully harming others and 82 percent did so without any provocation or sign of distress. The hourly frequency of unprovoked purposeful harm showed a curvilinear relation to age (Visit 1: 0.85, Visit 2: 1.42, Visit 3: 1.27). Compared to their interventions on prudential and pragmatic transgressions, mothers' interventions on moral transgressions involved increased use of physical interventions and direct commands, decreased use of softening interventions or distractions, and decreased relenting or compromising. Mothers also rated it as more important to discourage their children from moral transgressions than to discourage their children from prudential transgressions. These findings suggest that caregiver responses to transgressions provide unique opportunities for the early acquisition of the moral prohibition against harming others.