The Gini coefficient features prominently in Amartya Sen’s 1973 and 1997 seminal work on income inequality and social welfare. We construct the Gini coefficient from social-psychological building blocks, reformulating it as a ratio between a measure of social stress and aggregate income. We...

A utilitarian social planner who maximizes social welfare assigns the available income to those who are most efficient in converting income into utility. However, when individuals are concerned about their income falling behind the incomes of others, the optimal income distribution under...