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. We manipulate the level of common fate across treatments by varying the degree of harmony in the lottery structure. We observe higher contributions and stronger reciprocity in the most harmonious manipulation. Surprisingly, we find a positive relation between contributions and having experienced a favourable lottery outcome in the previous period, with the strength of this effect being inversely associated with the degree of harmony.