A key promise of democratic voting is that, by accounting for all constituents' preferences, it produces decisions that benefit the constituency overall. It is alarming, then, that all deterministic voting rules have unbounded distortion: all such rules - even under reasonable conditions - will sometimes select outcomes that yield essentially no value for constituents. In this paper, we show that this problem is mitigated by voters being public-spirited: that is, when deciding how to rank alternatives, voters weigh the common good in addition to their own interests. We first generalize the standard voting model to capture this public-spirited voting behavior. In this model, we show that public-spirited voting can substantially - and in some senses, monotonically - reduce the distortion of several voting rules. Notably, these results include the finding that if voters are at all public-spirited, some voting rules have constant distortion in the number of alternatives. Further, we demonstrate that these benefits are robust to adversarial conditions likely to exist in practice. Taken together, our results suggest an implementable approach to improving the welfare outcomes of elections: democratic deliberation, an already-mainstream practice that is believed to increase voters' public spirit.

翻译：民主投票的一个核心承诺是，通过考虑所有选民的偏好，它能做出惠及全体选民整体的决策。因此，所有确定性投票规则都存在无界扭曲这一事实令人警惕：所有此类规则——即使在合理条件下——有时也会选出对选民几乎毫无价值的方案。本文表明，若选民具有公益精神（即在决定如何排序备选方案时，除自身利益外还兼顾公共利益），这一问题将得到缓解。我们首先将标准投票模型泛化以刻画此类公益精神投票行为。在该模型中，我们证明公益精神投票能够实质性地——且在某些意义上单调地——降低多种投票规则的扭曲程度。值得关注的是，这些结果包含一项发现：若选民具备丝毫公益精神，部分投票规则的扭曲程度将随备选方案数量保持恒定。此外，我们证明这些优势对实践中可能存在的对抗性条件具有稳健性。综合来看，我们的研究结果为改善选举福利结果提供了一种可实施路径：即民主审议——这一已被广泛认为能提升选民公益精神的现有主流实践。