I. INTRODUCTION -- Moral sentiments and material interests: origins, evidence, and consequences / Herbert Gintis ... [et al.] -- II. THE BEHAVIORAL ECOLOGY OF COOPERATION -- The evolution of cooperation in primate groups / Joan B. Silk -- The natural history of human food sharing and cooperation: a review and a new multi-individual approach to the negotiation of norms / Hillard Kaplan, Michael Gurven -- Costly signaling and cooperative behavior / Eric A. Smith, Rebecca Bliege Bird -- III. MODELING AND TESTING STRONG RECIPROCITY -- The economics of strong reciprocity / Ernst Fehr, Urs Fischbacher -- Modeling strong reciprocity / Armin Falk, Urs Fischbacher -- The evolution of altruistic punishment / Robert Boyd ... [et al.] -- Norm compliance and strong reciprocity / Rajiv Sethi, E. Somanathan -- IV. RECIPROCITY AND SOCIAL POLICY -- Policies that crowd out reciprocity and collective action / Elinor Ostrom -- Reciprocity and the welfare state / Christina M. Fong ... [et al.] -- Fairness, reciprocity, and wage rigidity / Truman Bewley -- The logic of reciprocity: trust, collective action, and law / Dan M. Kahan -- Social capital, moral sentiments, and community governance / Samuel Bowles, Herbert Gintis.