Common Fate, Game Harmony and Contributions to Public Goods: Experimental Evidence

We experimentally study the effects of common fate on voluntary contributions to linear public goods. In each period, earnings are assigned to subjects according to the outcome of a lottery. In 'common fate', 'independent fate' and 'rival fate' treatments, the lottery outcomes of group members are (respectively) positively correlated, stochastically independent and negatively correlated. We observe the highest contributions and strongest reciprocity under common fate. Contrary to the game harmony hypothesis, contributions are not lower under rival fate than under independent fate. Surprisingly, under rival fate, having won the lottery in one period induces higher contributions in the next period.