A growing body of research suggests that prosocial behavior increases across adulthood. Yet, whether these age differences reflect “pure altruistic” or selfish motives, or the developmental mechanisms that underlie them, are largely unknown. Within a value-based decision framework, pure altruistic tendencies can be measured and distinguished from impure altruistic motives through neural-level information. Indeed, age differences in donations appear to be driven by a genuine concern for the well-being of others. Candidate mechanisms behind such pure altruistic changes need to show documented age differences and evidence of causal links to prosocial behavior. As examples, we discuss how three factors that meet these criteria––social norms, mood, and cognitive functioning––might explain age differences in pure altruistic tendencies.

越来越多的研究表明，亲社会行为在整个成年期都会增加。然而，这些年龄差异是否反映了“纯粹的利他”或自私的动机，或者它们背后的发展机制，在很大程度上尚不清楚。在基于价值的决策框架内，可以通过神经层面的信息来测量纯粹的利他倾向，并将其与不纯粹的利他动机区分开来。事实上，捐赠中的年龄差异似乎是出于对他人福祉的真正关心。这种纯粹利他性变化背后的候选机制需要显示有记录的年龄差异以及与亲社会行为的因果关系的证据。作为例子，我们讨论满足这些标准的三个因素——社会规范、情绪和认知功能——如何解释纯粹利他倾向的年龄差异。