In public good games, voluntary contributions tend to start of high and decline as the game is repeated. If high contributors are matched, however, contributions tend to stay high. We propose a formalization predicting that high contributors will selfselect into groups committed to charitable...

Several studies have demonstrated that individual contributions to public goods are increasing in others’ contributions. The underlying causes for this, however, are not yet fully understood. We present a model of duty-orientation in which moral responsibility is learned through observations...