Groups often need to perform repetitive tasks that require only one member’s effort at a time. For example, someone needs to carry garbage to the dump site when the garbage bin overflows in a household, order copier paper when it has run out in a workplace, and book a place when social club members hold a meeting. These tasks are commonly referred to as chores, housework or household chores in a household context, and office housework in a workplace context.
These tasks seem trivial and are rarely considered seriously. Nevertheless, they may involve a complicated burden-sharing problem, especially when group members differ in their cost to perform the task. Imagine a situation where someone in a group needs to carry garbage to the dump site. Everyone can do this, but it may take less effort for some members, possibly because they are physically stronger or have the dump site nearby. In this case, what is the most desirable way to share the burdens? Should every one take it on the same number of times irrespective of the cost heterogeneity (to achieve output equality), or should members with a lower cost take it on more often (to achieve net-benefit equality)? It may also be desirable if members with the lowest cost take it on all the time, which realizes efficiency.
The present research examined this burden-sharing problem adopting the framework of the volunteer’s dilemma . The volunteer’s dilemma is a type of social dilemmas, specifically public goods games. While a typical linear public goods game represents a group situation where everyone needs to incur a cost to produce a public good fully, the volunteer’s dilemma is a group situation where only one member needs to incur a cost to produce a public good fully This kind of situation may seem rare, but it is prevalent in the real world. As the examples above imply, we often face chores that require only one member’s effort at a time. The volunteer’s dilemma is also depicted in the famous fable Belling the Cat, which narrates the story of a group of mice deciding which mouse will undertake the task of attaching a bell to a cat.
I detailed these theoretical backgrounds regarding the volunteer’s dilemma in Chapter 1 of the present thesis. Specifically, Chapter 1 first introduce d a brief history of social dilemmas provided a definition of them, and classifie d them based on individual (i.e., whether it is always more beneficial for an individual to choose non-cooperation) and collective interests (i.e., whether it is always more beneficial for a group to have more cooperators) The aim of this classification wa s to demonstrate how the volunteer’s dilemma was different from other social dilemmas, specifically public goods games Furthermore, Chapter 1 classified the volunteer’s dilemma to show that repeated asymmetric volunteer’s dilemmas well reflect situations of interest in the present research――the burden-sharing problem introduced above Finally, Chapter 1 demonstrated that repeated asymmetric volunteer’s dilemmas involved the trade-off among three burden-sharing principles: efficiency, net-benefit equality, and output equality.
Chapter 2 introduced seven studies (n = 1,789) that addressed four questions regarding th e trade-off among three principles in repeated asymmetric volunteer’s dilemmas. The first two questions were (i) which burden-sharing principle participants perceived as most desirable and (ii) whether they acted according to the principle. As detailed in Chapter 2, I conducted Study 1 to examine the first question. Specifically, I
carried out an experiment to examine participants’ attitudes toward the three principles in repeated asymmetric volunteer’s dilemma games. The results showed that participants perceived net-benefit equality as the most desirable principle when they were asked to imagine a situation of the games from a third-party perspective.
In Study 2, which addressed the second research question I carried out an experiment to investigate participants’ actual behavior in repeated asymmetric volunteer’s dilemma games. Participants were matched with two other participants and played a game for 20-30 rounds. Some participants played a game as a “strong member,” who can volunteer at a lower cost than the other group members, while others played it as a “weak member.” The results revealed that while strong members acted according to the ideal (i.e., net-benefit equality), weak members’ behavior deviated from it ; they acted according to output equality.
In Study 3, I re-examined the first research question to confirm that net-benefit equality was deemed most desirable not only from the perspective of a third party but also from that of a weak member. The results of an experiment showed that participants deemed net-benefit equality as most desirable from the perspective of a third party, strong member, and weak member. Therefore, I concluded that there was some obstacle for weak members to act according to their ideal. This finding prompted the third research question:(iii) What was the obstacle to acting according to the desirable principle?
In Studies 4, 5a, and 5b, I addressed the third research question, examining three hypotheses: the perspective-taking-difficulty hypothesis (i.e., weak members may have misbelieved that strong members intended to achieve output equality), calculation-difficulty hypothesis (i.e., weak members may have failed to correctly calculate how many times each member should volunteer to achieve net-benefit equality), and coordination-difficulty hypothesis (i.e., weak members may have been un certain about who should volunteer in each round to achieve net-benefit equality and failed to coordinate their decision-making with other group members). I conducted repeated asymmetric volunteer’s dilemma games similar to those in Study 2. The results supported the coordination-difficulty hypothesis; weak members could not act according to net-benefit equality because they had difficulty coordinating their decision-making.
Even with coordination difficulty, weak members’ behavior in some groups was closer to net-benefit equality than that in other groups. Thus, Study 6 addressed the fourth research question: (iv) What kind of group dynamics led some weak members to act according to net-benefit equality even with coordination difficulty In Study 6, I first formally modeled participants’ decisions in the repeated asymmetric volunteer’s dilemma games in Studies 2, 4, and 5b. I compared seven models that assumed participants’ tendency of reinforcement learning net-benefit/output inequality aversion, and/or inclination to volunteer. After determining the best-fit model, which consisted of reinforcement learning net-benefit inequality aversion, and inclination to volunteer, I conducted a regression analysis. The dependent variable was the extent to which weak members acted according to net-benefit equality, and the independent variables included the parameters estimated in the best-fit model (e.g., the tendency of net-benefit inequality aversion of strong members). The results showed that weak members tended to act according to net-benefit equality when strong members consistently tried to achieve net-benefit equality, specifically when they volunteered once their net benefit became higher than other group members.
These findings have several contributions. As written in Chapter 3, for example, the finding that participants preferred net-benefit equality would be helpful in devising guidelines for real-life burden-sharing situations. Without knowing the trade-off among the three principles and people’s preference for net-benefit equality, one may intuitively develop a rule that deviates from net-benefit e quality. Such rules include having everyone take turns performing a repetitive task irrespective of how much cost each member needs to complete it (which aligns with output equality) and consistently assigning the task to a group member who can complete it with the lowest cost (which aligns with efficiency). These rules involve a discrepancy between the ideal and the reality, potentially leading to dissatisfaction among group members and even discord within the group. The present research suggests that creating guidelines that align with net-benefit equality would prevent such adverse outcomes.
In addition, the finding that coordination difficulty was the obstacle to acting according to net-benefit equality has several implications. First, it reveals the importance of studying situations entailing coordination. Although previous studies showed that coordination played a crucial role when people collaborated, most studies on social dilemmas mainly examined situations that did not involve coordination. Given that extensive empirical research on coordination is required because theoretically predicting how people resolve coordination problems is challenging, future work should concentrate on enhancing our understanding of how people address situations with coordination difficulty. Another implication of the finding is that, although people may feel frustrated as they cannot realize the principle they deem desirable in everyday burden-sharing situations they may resolve the problem if coordination difficulty is eliminated. It is important for future work to identify practical ways to reduce coordination difficulty in various real-life situations.
These tasks seem trivial and are rarely considered seriously. Nevertheless, they may involve a complicated burden-sharing problem, especially when group members differ in their cost to perform the task. Imagine a situation where someone in a group needs to carry garbage to the dump site. Everyone can do this, but it may take less effort for some members, possibly because they are physically stronger or have the dump site nearby. In this case, what is the most desirable way to share the burdens? Should every one take it on the same number of times irrespective of the cost heterogeneity (to achieve output equality), or should members with a lower cost take it on more often (to achieve net-benefit equality)? It may also be desirable if members with the lowest cost take it on all the time, which realizes efficiency.
The present research examined this burden-sharing problem adopting the framework of the volunteer’s dilemma . The volunteer’s dilemma is a type of social dilemmas, specifically public goods games. While a typical linear public goods game represents a group situation where everyone needs to incur a cost to produce a public good fully, the volunteer’s dilemma is a group situation where only one member needs to incur a cost to produce a public good fully This kind of situation may seem rare, but it is prevalent in the real world. As the examples above imply, we often face chores that require only one member’s effort at a time. The volunteer’s dilemma is also depicted in the famous fable Belling the Cat, which narrates the story of a group of mice deciding which mouse will undertake the task of attaching a bell to a cat.
I detailed these theoretical backgrounds regarding the volunteer’s dilemma in Chapter 1 of the present thesis. Specifically, Chapter 1 first introduce d a brief history of social dilemmas provided a definition of them, and classifie d them based on individual (i.e., whether it is always more beneficial for an individual to choose non-cooperation) and collective interests (i.e., whether it is always more beneficial for a group to have more cooperators) The aim of this classification wa s to demonstrate how the volunteer’s dilemma was different from other social dilemmas, specifically public goods games Furthermore, Chapter 1 classified the volunteer’s dilemma to show that repeated asymmetric volunteer’s dilemmas well reflect situations of interest in the present research――the burden-sharing problem introduced above Finally, Chapter 1 demonstrated that repeated asymmetric volunteer’s dilemmas involved the trade-off among three burden-sharing principles: efficiency, net-benefit equality, and output equality.
Chapter 2 introduced seven studies (n = 1,789) that addressed four questions regarding th e trade-off among three principles in repeated asymmetric volunteer’s dilemmas. The first two questions were (i) which burden-sharing principle participants perceived as most desirable and (ii) whether they acted according to the principle. As detailed in Chapter 2, I conducted Study 1 to examine the first question. Specifically, I
carried out an experiment to examine participants’ attitudes toward the three principles in repeated asymmetric volunteer’s dilemma games. The results showed that participants perceived net-benefit equality as the most desirable principle when they were asked to imagine a situation of the games from a third-party perspective.
In Study 2, which addressed the second research question I carried out an experiment to investigate participants’ actual behavior in repeated asymmetric volunteer’s dilemma games. Participants were matched with two other participants and played a game for 20-30 rounds. Some participants played a game as a “strong member,” who can volunteer at a lower cost than the other group members, while others played it as a “weak member.” The results revealed that while strong members acted according to the ideal (i.e., net-benefit equality), weak members’ behavior deviated from it ; they acted according to output equality.
In Study 3, I re-examined the first research question to confirm that net-benefit equality was deemed most desirable not only from the perspective of a third party but also from that of a weak member. The results of an experiment showed that participants deemed net-benefit equality as most desirable from the perspective of a third party, strong member, and weak member. Therefore, I concluded that there was some obstacle for weak members to act according to their ideal. This finding prompted the third research question:(iii) What was the obstacle to acting according to the desirable principle?
In Studies 4, 5a, and 5b, I addressed the third research question, examining three hypotheses: the perspective-taking-difficulty hypothesis (i.e., weak members may have misbelieved that strong members intended to achieve output equality), calculation-difficulty hypothesis (i.e., weak members may have failed to correctly calculate how many times each member should volunteer to achieve net-benefit equality), and coordination-difficulty hypothesis (i.e., weak members may have been un certain about who should volunteer in each round to achieve net-benefit equality and failed to coordinate their decision-making with other group members). I conducted repeated asymmetric volunteer’s dilemma games similar to those in Study 2. The results supported the coordination-difficulty hypothesis; weak members could not act according to net-benefit equality because they had difficulty coordinating their decision-making.
Even with coordination difficulty, weak members’ behavior in some groups was closer to net-benefit equality than that in other groups. Thus, Study 6 addressed the fourth research question: (iv) What kind of group dynamics led some weak members to act according to net-benefit equality even with coordination difficulty In Study 6, I first formally modeled participants’ decisions in the repeated asymmetric volunteer’s dilemma games in Studies 2, 4, and 5b. I compared seven models that assumed participants’ tendency of reinforcement learning net-benefit/output inequality aversion, and/or inclination to volunteer. After determining the best-fit model, which consisted of reinforcement learning net-benefit inequality aversion, and inclination to volunteer, I conducted a regression analysis. The dependent variable was the extent to which weak members acted according to net-benefit equality, and the independent variables included the parameters estimated in the best-fit model (e.g., the tendency of net-benefit inequality aversion of strong members). The results showed that weak members tended to act according to net-benefit equality when strong members consistently tried to achieve net-benefit equality, specifically when they volunteered once their net benefit became higher than other group members.
These findings have several contributions. As written in Chapter 3, for example, the finding that participants preferred net-benefit equality would be helpful in devising guidelines for real-life burden-sharing situations. Without knowing the trade-off among the three principles and people’s preference for net-benefit equality, one may intuitively develop a rule that deviates from net-benefit e quality. Such rules include having everyone take turns performing a repetitive task irrespective of how much cost each member needs to complete it (which aligns with output equality) and consistently assigning the task to a group member who can complete it with the lowest cost (which aligns with efficiency). These rules involve a discrepancy between the ideal and the reality, potentially leading to dissatisfaction among group members and even discord within the group. The present research suggests that creating guidelines that align with net-benefit equality would prevent such adverse outcomes.
In addition, the finding that coordination difficulty was the obstacle to acting according to net-benefit equality has several implications. First, it reveals the importance of studying situations entailing coordination. Although previous studies showed that coordination played a crucial role when people collaborated, most studies on social dilemmas mainly examined situations that did not involve coordination. Given that extensive empirical research on coordination is required because theoretically predicting how people resolve coordination problems is challenging, future work should concentrate on enhancing our understanding of how people address situations with coordination difficulty. Another implication of the finding is that, although people may feel frustrated as they cannot realize the principle they deem desirable in everyday burden-sharing situations they may resolve the problem if coordination difficulty is eliminated. It is important for future work to identify practical ways to reduce coordination difficulty in various real-life situations.
