As Quine has noted 'inveterately altruistic creatures have a pathetic tendency to die before reproducing their kind.' Hence it appears paradoxical that altruism is so pervasive among humans. The first steps in identifying specific genes that contribute to human altruism were taken by our group. In a seminal investigation, we demonstrated that the arginine vasopressin 1a receptor gene (AVPR1a) contributes to money allocations in the Dictator Game. In a follow up study we extended our findings and showed that the oxytocin receptor gene (OXTR) also contributes to altruism in two laboratory-based paradigms. The core question addressed by this proposal is how cultural and religious factors combined with genes, shape individual prosocial attitudes. The role of religious belief as a driver of altruistic and fair behaviors will be analyzed using a carefully designed portfolio of laboratory-based economic games. We hypothesize that religious belief interacts with genotype in predicting other regarding behavior. Importantly, we further hypothesize that religious affiliation will modify the neural imaging pattern when subjects participate in experimental economic games including the Dictator, Trust, Ultimatum and Third Party Punishment Games. The outcome of our study is to provide an empirical structure for understanding the mechanisms by which culture, religion and genes jointly mold human morality especially altruism, sense of fairness and trust. Clearly, understanding the biological roots of religious affiliation and how belief in a world religion meshes with prosociality is important for countries across the globe. We need to tap into this enormous resource (the positive sign of religion) to promote good works by our citizens and help all of us strive towards the achievement of a just society. Our group has an excellent track record giving us confidence that we can successfully do this project.