Defaults are powerful: whereas wisely set defaults increase prosocial choices, poorly set defaults promote selfish decisions. In two preregistered studies (NStudy 1 = 584, NStudy 2 = 587), we test whether distracting environments, compared to distraction-free environments, make people rely more on selfish than prosocial defaults. Participants completed repeated binary dictator games in a 2 (selfish default vs. prosocial default) x 2 (distraction vs. no distraction) within-subjects design. Results from both studies and an internal meta-analysis provide no support for the hypothesis. Whereas participants accepted prosocial more than selfish defaults (in Study 1 and in an internal meta-analysis), the existence (vs. absence) of distraction did not affect default acceptance differentially for selfish versus prosocial defaults. Exploratory cluster analyses showed that around 75% of participants made choices based on their social preference, thereby showing little to no response to defaults. The remaining 25%, however, were responsive to defaults, resulting in an overall higher fraction of prosocial choices made when defaults are prosocial (vs. selfish). Overall, despite most participants being non-responsive, findings highlight the aggregate benefit of setting prosocial defaults, both in distracting and non-distracting environments.

We discuss willful ignorance and information avoidance in prosocial decisions from the perspective of economic theory, i. e. based on the ideas of utility maximization and the instrumental value of information. We provide a definition of information avoidance, empirical evidence from a paradigmatic experiment, and discuss the motives behind the phenomenon. We discuss its relevance in applications and avenues for future research.

Previous literature has shown that people are often reluctant to learn whether individually profitable actions have negative consequences for others. In an experimental allocation decision, we vary the ‘inconvenience’ of becoming informed about the payoffs of another player by changing the costs and benefits of choosing the fair outcome. Lowering the cost of fairness turns out to have a multiplier effect, raising both altruistic choices of informed subjects and the fraction of subjects that chooses to become informed. Thus, in situations of uncertainty, subsidizing altruistic choices to decision makers is an effective tool for raising social welfare. By contrast, variations in the size of recipients’ potential benefit have a smaller and insignificant effect on ignorance and fair choices.

In a system of proportional representation, we study the interaction between a voter’s turnout decision and her party choice, and how these relate to party polarization. Models of strategic interaction with instrumental voting, such as Nash and Quantal Response, predict such interaction effects, while Naive Voting models do not. In particular, the instrumental voting models predict (i) a Polarization Effect: reduced strategic party choice when voting is voluntary makes voters more likely to vote for extreme parties (conditional on voting at all); (ii) an Extremist Effect: voters supporting extreme parties are most likely to vote; (iii) a Turnout Effect: party polarization increases voter turnout. We provide data from a laboratory experiment that provide some support for these theoretical predictions. In addition, we provide supporting empirical evidence from real-world elections. Thus, the interaction between turnout and strategic voting that has been neglected in most of the previous literature is shown to be important, as predicted by models of instrumental voting.

Humans frequently cooperate to achieve benefits unattainable through selfish behaviour. Punishment of free-riders is key for sustaining cooperation but also costly, raising questions about the origins of such behaviour. Some evolutionary models suggest that individuals may be willing to hurt unknown others in competitive environments. However, empirical evidence about the effect of the scale of competition on strategies involving hurtful behaviour in human groups, such as spite, retaliation for hurting, and punishment of free-riders, is missing. Using a laboratory experiment, we manipulate the scale of competition to investigate its influence on hurtful and helpful behaviours, between unknown humans in an indirect reciprocity game. We observe distinct behavioural patterns between local and global competition. When competition is local and thus confined to take place within isolated groups we find frequent hurting as an expression of spite and retaliation. In contrast, when competition extends globally across several groups, hurting is used primarily for punishment of free-riders whereas helping behaviour is rewarded, which together promotes cooperation. Thus, while isolated competition fosters inefficient, antisocial behaviour, global competition encourages prosociality and cooperation.