The evolution of cooperation is an unsolved research topic and has been investigated from the viewpoint of not only biology and other natural sciences but also social sciences. Much extant research has focused on the evolution of cooperation among peers. While, different players belonging to different organizations play different social roles, and players playing different social roles cooperate together to achieve their goals. We focus on the evolution of cooperation in linear division of labor that is defined as follows: a player in the i-th role interacts with a player in the i + 1-th role, and a player in the n-th role achieves their goal (1 ≤ i < n) if there are n roles in the division of labor. We take the industrial waste treatment process as an example for illustration. We consider three organizational roles and B is the i-th role. The player of B can choose two strategies: legal treatment or illegal dumping, which can be interpreted as cooperation or defection (i = 1-3). With legally required treatment, the player of B pays a cost to ask the player of B to treat the waste (j = 1, 2). Then, the cooperator of B pays a cost to treat the waste properly. With illegal dumping, the player of B dumps the waste and does not pay any cost (i = 1-3). However, the waste dumped by the defector has negative environmental consequences, which all players in all roles suffer from. This situation is equivalent to a social dilemma encountered in common-pool resource management contexts. The administrative organ in Japan introduces two sanction systems to address the illegal dumping problem: the actor responsibility system and the producer responsibility system. In the actor responsibility system, if players in any role who choose defection are monitored and discovered, they are penalized via a fine. However, it is difficult to monitor and detect the violators, and this system does not work well. While, in the producer responsibility system, the player in B is fined if the player cannot hand the manifest to the local administrative organ because the players of B (i = 1-3) who choose defection do not hand the manifest to the player of B. We analyze this situation using the replicator equation. We reveal that (1) the three-role model has more empirical credibility than the two-role model including B and B, and (2) the producer responsibility system promotes the evolution of cooperation more than the system without sanctioning. (3) the actor responsibility system does not promote the evolution of cooperation if monitoring and detecting defectors is unsuccessful.

To ensure sustainability, overcoming intergenerational conflict is vital, and social systems supporting decision-making that takes into account the benefits to future generations is thus critically important. One promising approach in such social systems is introducing “imaginary future generations” who act as representatives for the benefits of future generation in actual, present-day decision-making situations. In this study, we explore the effects and implications of participants’ experiences as representatives of imaginary future generation. We conducted a citizens’ participatory debate on creating a vision and appropriate policies associated with public facilities and housing in a town in Japan, and examined how the thinking patterns and decisions of the participants shifted as a result of debating from the perspectives of both current and imaginary future generations. Based on analyses of a questionnaire and the keywords in answers to a worksheet provided to the participants, we demonstrate that through their experiences as representatives of imaginary future generations, a clear shift in perspective occurred, with increases in self-reflective viewpoint. We also found that the shared viewpoints of the current and future generations existed within the individuals. These findings hint at how we can develop institutions and social systems that facilitate sustainable decision-making.

Despite global commitments and efforts, a gender-based division of paid and unpaid work persists. To identify how psychological factors, national policies, and the broader sociocultural context contribute to this inequality, we assessed parental-leave intentions in young adults (18-30 years old) planning to have children (N = 13,942; 8,880 identified as women; 5,062 identified as men) across 37 countries that varied in parental-leave policies and societal gender equality. In all countries, women intended to take longer leave than men. National parental-leave policies and women's political representation partially explained cross-national variations in the gender gap. Gender gaps in leave intentions were paradoxically larger in countries with more gender-egalitarian parental-leave policies (i.e., longer leave available to both fathers and mothers). Interestingly, this cross-national variation in the gender gap was driven by cross-national variations in women's (rather than men's) leave intentions. Financially generous leave and gender-egalitarian policies (linked to men's higher uptake in prior research) were not associated with leave intentions in men. Rather, men's leave intentions were related to their individual gender attitudes. Leave intentions were inversely related to career ambitions. The potential for existing policies to foster gender equality in paid and unpaid work is discussed.

Background. Many studies have shown that sanctions promote cooperation in social dilemma situations. However, it has also been suggested that sanctions have a negative effect. The interactions among people and systems need to be considered to examine the consequences of sanctions. Aim. We examined whether rewards and mutual punishment increased non-cooperation. We regarded illegal industrial waste dumping as a social dilemma in which everyone bears the burden of the cost of illegal dumping, legal treatment is cooperative behavior, and illegal dumping is non-cooperative behavior. Method. We used the Industrial Waste Illegal Dumping Game. This game simulates the structure of industrial waste treatment (incomplete surveillance, various industries with different roles and payoffs, cost of cooperation, etc.) in addition to the social dilemma structure. Players take on roles in industrial waste treatment, negotiating and dealing with other players, and treating industrial waste. We set three conditions. In the reward condition, players can earn rewards by rapidly treating industrial waste. In the mutual punishment condition, players can mutually monitor and punish each other. In the control condition, neither reward nor punishment exists. Results. Non-cooperation occurred more frequently in the reward condition than in the control condition. Conversely, there was no difference in non-cooperation between the mutual punishment and control conditions. Players under the reward condition did not gather information proactively, and information on benefits was not shared. Conclusion. This study showed that sanctions caused non-cooperation. Social dynamics should be considered when evaluating the effectiveness of sanctions. Gaming allows us to examine social consequences, including social dynamics, which leads to discoveries not possible through traditional methods.