 Often the individuals who are the “targets” of altruistic behavior are selected for such treatment because of a personal tie between the benefactor and the beneficiary. If A was extraordinarily kind to B when B was a child, and at a later time B is in a position to help A out of a difficult situation, the help B gives to A is altruistically motivated, even though their common past explains why it is A that B has chosen to help (rather than a stranger in need). Here it is assumed that B is not promoting A’s well-being as a mere means to his own (B’s) own well-being. If that were so, B would not be benefiting A for A’s sake, but only for B’s sake. (A further assumption is that B is not motivated simply by a sense that he owes repayment to A; rather, he not only feels indebted to A but also genuinely cares about him.) The people whom we treat altruistically are often those to whom we have a sentimental attachment, or towards whom we feel grateful. But that is not the only possibility. Some altruistic acts are motivated simply by a recognition of the great need of those who benefit from them, and the benefactor and beneficiary may be strangers to each other. 