There are many kinds of prosocial behavior - behavior that benefits others, such as helping, cooperation, and sympathy. Such impulses arise early in life. Researchers agree that young children respond sympathetically to companions in distress, usually before their second birthday (Hay, 1994; Kochanska, 1993). The term altruism is usually reserved for behavior that is aimed at helping others, requires some self-sacrifice and is not performed for personal gain. Batson and colleagues (1989) believe that we help out of empathy - the ability to take the perspective of others, to put ourselves in their place.
Commitment is another factor influencing altruism. We are more likely to behave in an altruistic fashion in the context of relationships to which we are deeply committed (Powell & Van Vugt, 2003). The influence of commitment is strongest when the cost of an altruistic act is high. For instance, you would probably be more likely to volunteer to donate a kidney, let's say, to a family member than to a stranger.
The degree to which society values altruism is another variable that can influence individual decisions about altruistic behavior. Cultures vary in their norms for helping others - that is, their social responsibility norms. According to Miller and others (1990), people in the United States tend to feel an obligation to help family members, friends and even strangers in life-threatening circumstances but only family members in moderately serious situations. In contrast, in India the social responsibility norm extends to strangers whose needs are only moderately serious or even minor.