Discussions of deliberation and political participation have long speculated that forms of public consultation that involve shared discussion and decision about public issues will foster ‘public spiritedness’ - a greater support for policies of broad rather than narrow public interest. J. S. Mill, building on Tocqueville’s account of town meetings and juries in America, praised institutions that serve as ‘schools of public spirit’ - local decision-making bodies where the interests of the whole community are discussed and individual citizens have some role in decisions. More recent writers like Jane Mansbridge have continued the speculation, but have encountered difficulty finding clear empirical confirmation (Mill 1861  especially Chapters 1 and 8: 78-9, 171-3; Mansbridge 1999).
Mill argued that when the private citizen participates in public functions
[h]e is called upon, while so engaged, to weigh interests not his own; to be guided in case of conflicting claims, by another rule than his private partialities; to apply, at every turn, principles and maxims which have for their reason of existence the general good. He is made to feel himself one of the public and whatever is in their interest to be his interest.
(Mill 1861 )
Mill called for more ‘schools of public spirit’ and experimentation with their design. In a sense the Deliberative Poll, like other microcosmic deliberations is potentially a ‘school of public spirit’. But whether or not it functions that way is an empirical question (de Tocqueville 1863 ; Mansbridge 1999; Fishkin et al. 2010).11 We have already seen in China that when local citizens were gathered to deliberate about infrastructure choices, they increased their support for projects, among the thirty possible ones, that would serve a broader community, as opposed to projects that would benefit only a single village. In addition, in the eight Texas projects on energy choices, the percentage willing to pay more on their monthly utility bills in order to provide wind power to the whole community rose by about thirty points, averaged over the eight projects. And the percentage willing to pay more on their monthly bills in order to provide conservation efforts for the community (demand side management) also rose about thirty points. The notion that one would pay more on a monthly bill in order to subsidize the cost of windmills, or in order to subsidize conservation efforts, seems an indication, in at least a small way that one is willing to contribute to the broader public interest.
A similar result can be inferred from the project in New Haven about local issues facing the fifteen towns in the metropolitan region. In Connecticut, the town is the unit of government and at the beginning, there was a strong presumption that the towns would not share revenue amongst each other. But after deliberation, there was considerable movement toward revenue sharing to promote new development that might benefit the region as a whole. The experimental design of this project allowed us to attribute the movement to the process of discussing the issues together, rather than to learning at home in anticipation of the event or any of the other elements of the process (Farrar et al. 2010).