Warneken, F., &Tomasello, M. (2006). Altruistic helping in human infants and young chimpanzees. science, 311(5765), 1301-1303.

Human beings routinely help others to achieve their goals, even when the helper receives no immediate benefit and the person helped is a stranger. Such altruistic behaviors (toward non-kin) are extremely rare evolutionarily, with some theorists even proposing that they are uniquely human. Here we show that human children as young as 18 months of …

Grant, A. M., &Sonnentag, S. (2010). Doing good buffers against feeling bad: Prosocial impact compensates for negative task and self-evaluations.

Although evidence suggests that negative task and self-evaluations are associated with emotional exhaustion, little research has examined factors that buffer against these effects. We propose that perceived prosocial impact, the experience of helping others, compensates for negative task and self-evaluations by focusing attention on positive outcomes for others. In Study 1, perceived prosocial impact attenuated …