The Rise of Deliberative Prosociality

We examine how social behaviours emerge and stabilise in human development.Children (N = 537; 3-10 years) were randomly assigned to respond under timepressure (intuitively) or under time delay (deliberatively) to a series of tasks(Public Goods Game, Dictator Game, Ultimatum Game, Deception Game, MoralDilemmas). Factor analysis across tasks reveals three latent dimensions of socialbehaviour: Prosociality (capturing cooperative, altruistic, and honest actions),Social Optimism (capturing beliefs about others’ cooperative behaviour), andAcquiescence (capturing a general tendency to accept offers). Intuitive responsesare more prosocial than deliberative ones in early childhood; however, this differencediminishes with age as deliberative reasoning increasingly supports prosocialchoices. Social Optimism remains stable across age and decision mode, whileAcquiescence is unaffected by decision mode but declines with age. These findingssuggest that prosocial behaviour is intuitive in early childhood but becomesintegrated into deliberate reasoning through development.