School of Statistics and Mathematics, Yunnan University of Finance and Economics, Kunming 650221, China.
Interdisciplinary Research Institute of Data Science, Shanghai Lixin University of Accounting and Finance, Shanghai 201209, China.
Chaos. 2023 Dec 1;33(12). doi: 10.1063/5.0180979.
Income redistribution, which involves transferring income from certain individuals to others, plays a crucial role in human societies. Previous research has indicated that tax-based redistribution can promote cooperation by enhancing incentives for cooperators. In such a tax system, all individuals, irrespective of their income levels, contribute to the tax system, and the tax revenue is subsequently redistributed to everyone. In this study, we relax this assumption by introducing a tax threshold, signifying that only individuals with incomes exceeding the threshold will be subject to taxation. In particular, we employ the spatial public goods game to investigate the influence of tax rates-the percentage of income allocated to tax-and tax thresholds, which determine the income level at which individuals become taxable, on the evolution of cooperation. Our extensive numerical simulations disclose that tax thresholds produce complex outcomes for the evolution of cooperation, depending on tax rates. Notably, at low tax rates (i.e., below 0.41), as the tax threshold increases, discontinuous phase transitions in cooperation performance suggest the presence of multiple intervals of effective tax thresholds that promote peak cooperation levels. Nevertheless, irrespective of the chosen tax rate, once the tax threshold surpasses a critical threshold, the redistribution mechanism fails, causing the collapse of cooperation. Evolutionary snapshots show that self-organized redistribution forms an intermediary layer on the peripheries of cooperative clusters, effectively shielding cooperators from potential defectors. Quantitative analyses shed light on how self-organized redistribution narrows the income gap between cooperators and defectors through precise identification of tax-exempt entities, thereby amplifying the cooperative advantage. Collectively, these findings enhance our comprehension of how income redistribution influences cooperation, highlighting the pivotal role of tax thresholds.
收入再分配，即将收入从某些个体转移给其他人，在人类社会中起着至关重要的作用。先前的研究表明，基于税收的再分配可以通过增强合作者的激励来促进合作。在这样的税收制度中，所有个体，无论其收入水平如何，都要为税收制度做出贡献，而税收收入随后会再分配给每个人。在本研究中，我们通过引入税收门槛来放松这一假设，即只有收入超过门槛的个体才需要纳税。具体来说，我们采用空间公共物品博弈来研究税率（分配给税收的收入百分比）和税收门槛（决定个体开始纳税的收入水平）对合作演化的影响。我们广泛的数值模拟揭示了税收门槛对合作演化的复杂影响，这取决于税率。值得注意的是，在低税率（即低于 0.41）下，随着税收门槛的增加，合作表现的不连续相变表明存在多个有效的税收门槛区间，这些区间可以促进合作水平达到峰值。然而，无论选择的税率如何，一旦税收门槛超过一个临界门槛，再分配机制就会失效，导致合作崩溃。演化快照表明，自组织的再分配在合作簇的外围形成了一个中间层，有效地保护了合作者免受潜在的叛徒的影响。定量分析揭示了自组织的再分配如何通过准确识别免税实体来缩小合作者和叛徒之间的收入差距，从而放大合作优势。总的来说，这些发现增强了我们对收入再分配如何影响合作的理解，强调了税收门槛的关键作用。
