 An alternative reason for existence of privately provided public goods is that people do not always act in a fully self-interested manner. Most economic models assume that people care only about the benefits a public good provides to them, but people in fact also care about the outcomes for others. Donations to charity and political campaigns are obvious examples. One way to model this is to assume that the act of giving itself provides additional utility distinct from the utility obtained from the aggregate level of provision of the public good (Steinberg 1987).