People contribute more to public goods, the more others give ('crowding-in'). We investigate two possible causes of crowding-in: reciprocity, the usual explanation, and conformism, a neglected alternative. The issue is important since conformism has more scope to bring about endogenous social...

People contribute more to public goods, the more others give (“crowding-in”). We investigate two possible causes of crowding-in: reciprocity, the usual explanation, and conformism, a neglected alternative. The issue is important since conformism has more scope to bring about endogenous...