We model group formation as a response to relative deprivation. We employ two measures of relative deprivation. We show that in the case of each of these measures the process of deprivation-induced self-selection into groups reaches a steady state, and that the steady-state distribution differs...

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...