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...

We report results from a dictator game experiment with nurse students and real estate broker students as dictators, and Amnesty International as the recipient. Although brokers contributed substantial amounts, nurses contributed significantly more, on average 76 percent of their endowment. In a...