Political Science

Participants in laboratory games are often willing to alter others' incomes at a cost to themselves, and this behaviour has the effect of promoting cooperation 1-3 . What motivates this action is unclear: punishment and reward aimed at promoting cooperation cannot be distinguished from attempts to produce equality 4 . To understand costly taking and costly giving, we create an experimental game that isolates egalitarian motives. The results show that subjects reduce and augment others' incomes, at a personal cost, even when there is no cooperative behaviour to be reinforced. Furthermore, the size and frequency of income alterations are strongly influenced by inequality. Emotions towards top earners become increasingly negative as inequality increases, and those who express these emotions spend more to reduce above-average earners' incomes and to increase below-average earners' incomes. The results suggest that egalitarian motives affect income-altering behaviours, and may therefore be an important factor underlying the evolution of strong reciprocity 5 and, hence, cooperation in humans.

We analyze a model of a dynamic political competition between two policy-motivated parties under uncertainty. The model suggests that electoral mandates matter: increasing the margin of victory in the previous election causes both parties to shift towards policies preferred by the winner, and the loser typically shifts more than the winner. The model also provides potential answers to a number of empirical puzzles in the field of electoral politics. In particular, we provide possible explanations for why close elections may lead to extreme platforms by both parties, why increased extremism in the platform of one party may lead to greater moderation in the platform of the other party, and why increasing polarization of the electorate causes winning candidates to become more sensitive to mandates. We also show that, contrary to previous findings, increasing uncertainty sometimes decreases platform divergence. Finally, we pay special attention to the proper methodology for doing numerical comparative statics analysis in computational models.

Altruistic punishment increases cooperation in human social exchange. However, the mechanisms underlying punishment remain in question. Punishment is consistent with both a desire to enforce cooperative norms and an egalitarian motive seeking to eliminate income disparities. Recent evidence indicates that egalitarian motives yield behavior that resembles costly punishment: individuals are willing to alter others' incomes, at a considerable cost, in order to attain equality. This work, however, only hints at a link between egalitarian preferences and altruistic punishment. Here we conduct experiments in which subjects participate in both a game that measures individuals' preferences for income equality and a modified public goods game that magnifies the influence of sanctioning motives. Controlling for income differences and the order of experiments, our results provide the first direct laboratory evidence that the same individuals who care about equality are those who are most willing to punish free-riders in public goods games. In an independent replication, we also show that egalitarian motives predict altruistic punishment behavior in a standard public goods game. Inequality aversion thus appears to play an important role in the income-altering behavior that facilitates cooperation in human groups.

Primatological and archeological evidence along with anthropological accounts of hunter-gatherer societies indicate that lethal between-group violence may have been sufficiently frequent during our ancestral past to have shaped our evolved behavioral repertoire. Two simulations explore the possibility that heroism (risking one's life fighting for the group) evolved as a specialized form of altruism in response to war. We show that war selects strongly for heroism but only weakly for a domain-general altruistic propensity that promotes both heroism and other privately costly, group-benefiting behaviors. A complementary analytical model shows that domain-specific heroism should evolve more readily when groups are small and mortality in defeated groups is high, features that are plausibly characteristic of our collective ancestral past.

The authors develop an agent-based model of dynamic parties with social turnout built upon developments in different fields within social science. This model yields significant turnout, divergent platforms, and numerous results consistent with the rational calculus of voting model and the empirical literature on social turnout. In a simplified version of the model, the authors show how a local imitation structure inherently yields dynamics that encourage positive turnout. The model also generates new hypotheses about the importance of social networks and citizen-party interactions.

As reflected in theory, laboratory evidence, and field studies, altruistic punishment of defectors promotes cooperation. Costly selfenforcement of socially optimal behavior has a number of independent links in political science, economics, psychology, sociology, computer science, and biology. This paper integrates the study of sanctions-based provision of public goods in the social sciences with the research on evolutionary adaptedness of altruistic punishment in the life sciences. Altruistic punishment appears to be (1) economically rational, (2) evolutionarily robust as an individual propensity and as a cultural norm, (3) normatively more appealing than tit-for-tat, which is a reciprocal punishment by defection, and (4) socially common. The theoretical and empirical importance of altruistic punishment has immediate policy implications. Examination of commons around the world suggests that privatization and centralized coercion are not the only solutions to the tragedy of the commons. A viable policy alternative is to facilitate the evolution of the commons as a common-property regime with its own norms and a certain degree of independence.

Abstract Past models treat economic inequality as an exogenous condition that can provide individuals a dominant incentive to produce collective goods unilaterally. Here we part with that tradition so as to treat economic inequality and collective action as endogenous, and to examine whether economic inequality can foster collective action even when all individuals can gain from free-riding.

Laboratory experiments indicate that many people willingly contribute to public goods and punish free riders at a personal cost. We hypothesize that these individuals, called strong reciprocators, allow political parties to overcome collective action problems, thereby allowing those organizations to compete for scarce resources and to produce public goods for like-minded individuals.

Abstract Cooperation pervades life on earth, but opportunities for free-riding make any single instance of it unlikely. What, then, enabled the evolution of cooperation? Information mechanisms such as reputation and tags provide one possibility, as they help organisms identify potential free-riders. The plausibility of these mechanisms, however, is questionable: reputation systems involve sophisticated cognitive abilities and arbitrary tags exemplify symbolic information—both of which are biologically rare.

Abstract We construct a decision-theoretic model of turnout, in which individuals maximize their subjective expected utility in a context of repeated elections. In the model a nonnegative signaling motivation to vote exists for all citizens, regardless of their ideology or beliefs about the closeness of the election, and is proportional to a citizen's external efficacy, patience, and electoral pessimism. We find tentative support for all three effects in an empirical model of turnout using NES data (1976-1988).

Abstract A stylized model of three parties choosing an amendment agenda and voting over three policy alternatives is analyzed. The analysis yields a classification of five types of voters: random, sincere, strategic, risk-averse, and EUS (expected utility sophisticated) proposed by Enelow (J. Polit. 43: 1062–1089, 1981).

ABSTRACT We analyze a model of a dynamic political competition between two policy-motivated parties under uncertainty. The model suggests that electoral mandates matter: increasing the margin of victory in the previous election causes both parties to shift towards policies preferred by the winner, and the loser typically shifts more than the winner. The model also provides potential answers to a number of empirical puzzles in the field of electoral politics.

Though most students find it a challenge to work while completing their education, Michael Paul Jackson thought it remarkably easy to do so. During his tenure at Radford University, Jackson—an ordinary student with no business experience—made $120,000 via a sly online auction business.

Abstract The willingness of people to risk their lives fighting on behalf of their nation (which we call heroism) is a background assumption in the study of war, thus of international relations, but also an evolutionary puzzle. We use two computer simulations to explore the possibility that heroism could have evolved as a domain specific form of altruism, selected through humans' ancient past as a consequence of warfare.

Abstract Recent evidence suggests that parties are responsive to elections, adjusting their post-electoral policies in the direction of the winner and in proportion to the margin of victory. If voters believe that parties are responsive, then they may have an incentive to vote strategically. Specifically, those who prefer moderate policies have an incentive to engage in mandate balancing, the act of voting for the party expected to lose in order to reduce the margin of victory.

Humans often cooperate, voluntarily paying an individual cost to supply a benefit to others. Public good experiments show that punishment induces a high level of cooperation, even when it is costly to the punisher. 1 It is unclear, however, what motivates individuals to engage in costly punishment: a desire to retaliate against non-cooperators or a desire to reduce inequality among group members.