We test an assortative mechanism whereby groups are formed endogenously, through the use of voting. Once formed, groups play a public-goods game, where the social value of an incremental contribution to the group account increases with the size of the group. Societies of nine people are...

Efficient coordination in large groups is a fundamental issue in economic organizations. We consider the weak-link game with the feature of economies of scale that is necessary for voluntary group growth, in a minimal setup with exit and merger options that allows for bi-directional changes in...