A conceptual and mathematical model of a social community behavior in a choice situation under a veil of ignorance, where two alternative policies—Rawlsian maximin and Harsanyian utilitarianism—can be implemented through the aggregation of individual preferences over these two policies, is constructed and investigated. We first incorporate in our conceptual model psychological features such as risk-aversion and prosocial preferences that likely underlie choices of welfare policies. We secondly develop and select the mathematical model presented it by means of an autonomous system of ordinary differential equations. A qualitative analysis of this system global phase-plane behavior shows possible tendencies of community development under social choices over Rawlsian or utilitarian societies depending on psychological parameters such as risk aversion and prosocial preferences. © 2015, Springer-Verlag Berlin Heidelberg.