Can lab experiments on student populations serve to identify the motivational forces present in society at large? We address this question by conducting, to our knowledge, the first study of social preferences that brings a nationally representative population into the lab, and we compare their...

Why do people in rich countries not transfer more of their income to people in the world's poorest countries? To study this question and the relative importance of needs, entitlements, and nationality in people's social preferences, we conducted a real effort fairness experiment where people in...

This paper presents a formal theory of reciprocity. Reciprocity means that people reward kind actions and punish unkind ones. The theory takes into account that people evaluate the kindness of an action not only by its consequences but also the intention underlying this action. The theory...