Prosocial behavior encompasses all actions that benefit others without having a direct (material) gain for the actor. Typical prosocial behavior seen in children: sharing, helping, and cheering up. Several factors influence the child's tendency to act prosocially, including friendship, justice, reputation, and reciprocity.
PB develops in the second year of life, when children start to help others and later engage in sharing and cheering up. Fairness, friendship and social pressure are aspects that guide prosocial behavior and develop until the age of 5-6.
PB must not be confused with morals. Morals describe general standards of behavior where crossing them is sanctioned. Prosocial behavior and morals are generally measured differently in developmental psychology (prosocial behavior can be unjust, and the executive functions of young children are considered to be too early in development for actual morals). At age 3, children show first signs of guilt and their understanding of general rules. They also protest unfair distributions of resources and later (age 5) give affirmation for fair distributions.
The origins of PB are heavily disputed in literature, with some arguing that PB is genetically programmed into us (Hamlin, 2013; Hamlin et al. 2007), while others argue that we learn PB from social interaction (Dahl, 2015) (this last point is supported by the fact that some of the kognitive skills needed for PB like speech and perspektive shifts only develop over time) Todo: Connect these views with Compassion is baked into our DNA
The Helper-Hinderer paradigm presented by Hamlin et al. (2017) argues that young children already have a basic sense of morals, as they prefer helping agents over hindering agents. This evidence is, however, heavily disputed in literature.