10 QUARTERLY JOURNAL OF ECONOMICS 现 0 a=0,h=ho FIGURE I Regions of Giving g and Probability of Home Presence h Figure indicates the different regions for giving,no giving lg=0),small giving 0<g<g"),giving equal tog",and large giving (g >g").and the different regions ility of being at home,avoiding thes icitor [h hol,and seeking pressure paran piteful agents(a <0)if the social pressure cost S is large enough (S>u'(W)and hence a<). Giving via Mail.Conditional on not being at home,a giver who was informed about the fund-raising via a flyer decides whether to give via mail gm.Note that the only reason to give via mail is altruism.Giving via mail is increasing in altruis provided 0.For given altruisn 0 the leve giving via mail re eceived by the charity(g(a))is always smaller than the level of giving in person conditional on being at home (g(a,S)) (Lemma 1B). Presence at Home.In the first stage,the giver opens the door with robability ho if the visit is ticipa (no yer or with probability 1-r,despite a flyer). f the visit is anticipated (flyer),she optimizes h given her utility from being at home, u(W-g)+av(g,G_i)-s(g*),and her utility from not being at home,u (W-gm)+av (0gm,G_i):10 QUARTERLY JOURNAL OF ECONOMICS FIGURE I Regions of Giving g and Probability of Home Presence h Figure indicates the different regions for giving, no giving [g = 0], small giving [0 < g < gs], giving equal togs, and large giving [g > gs], and the different regions for the probability of being at home, avoiding the solicitor [h < h0], and seeking the solicitor [h > h0]. The regions are a function of the altruism parameter a and of the social pressure parameter S. spiteful agents (a < 0) if the social pressure cost S is large enough (S > u0 (W) and hence a < 0). Giving via Mail. Conditional on not being at home, a giver who was informed about the fund-raising via a flyer decides whether to give via mail gm. Note that the only reason to give via mail is altruism. Giving via mail is increasing in altruism, provided θ > 0. For given altruism a, the level of giving via mail received by the charity (θg∗ m (a)) is always smaller than the level of giving in person conditional on being at home (g∗ (a, S)) (Lemma 1B). Presence at Home. In the first stage, the giver opens the door with probability h0 if the visit is unanticipated (no flyer or, with probability 1 − r, despite a flyer). If the visit is anticipated (flyer), she optimizes h given her utility from being at home, u (W − g∗) + av (g∗, G−i) − s (g∗), and her utility from not being at home, u (W − g∗ m) + av (θg∗ m, G−i): by guest on September 20, 2012 http://qje.oxfordjournals.org/ Downloaded from