Infants' unprovoked acts of force toward others.

Infants harm others at higher rates than older children and adults. A common explanation is that infants fail to regulate their frustration, becoming aggressive when they do not get what they want. The present research investigated whether infants also use force against others without provocation, for instance because they seek to explore the consequences of hitting or try to pet someone using too much force. Two studies with infants aged 11 to 24 months investigated infants' use of force against others in everyday life using maternal report (Study 1) and direct observation (Study 2). In both studies, a large proportion of infants' acts of force were unprovoked and occurred without signs of infant distress. Unlike provoked acts, unprovoked acts showed a decrease late in the second year and were positively associated with reports of infant pleasure-proneness. The presence of unprovoked acts of harm may reflect that infants' actions are not reliably guided by an aversion for harming others and may provide unique opportunities for early moral development.