Chapter 2 Various Types of Social Dilemma

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1 Chapter 2 Various Types of Social Dilemma In order to examine the pragmatic methods of solving social dilemmas, it is important to understand the logical structure of dilemmas that underpin actual real-life problems. To this end, and also to facilitate the basic understanding of social dilemmas, the categories and types of representative social dilemmas will be reviewed in the following section. Incidentally, note that these categories are not exclusive to each other, but include areas of overlap. Moreover, refer also to Komorita and Parks (1994) and Yamagishi (1989) for more detailed descriptions on the categories of these dilemmas. 2.1 Prisoner s Dilemma The prisoner s dilemma (or PD game) is perhaps one of the simplest ways to express a social dilemma. Two friends are arrested, and as prisoners they are kept in solitary confinement; periodically they are interrogated separately; they have no way of communicating with each other. Their interrogator then puts a proposal to them: If you confess that your buddy is the ringleader, then you will be regarded as his sidekick and will receive a short sentence. The jail terms are 15 years for the ringleader, and one year for the sidekick. But if both of you confess that the other is the ringleader, then we regard both of you as equally guilty, and you will be imprisoned for 10 years. However, if both of you keep silent, you will be imprisoned for 3 years. The interrogators offer is shown in Fig Then, each prisoner may assess their situation as follows: What happens if my buddy is tempted by the interrogator s proposal and makes a confession? If I then confess, it means that as both of us have confessed, since there is no ringleader or sidekick, we will both receive 10 years in jail. If I do not confess, I will be regarded as the ringleader anyway and will receive the heavier penalty of 15 years. That means it is better for me to make a confession. Springer Japan 2017 S. Fujii, Prescription for Social Dilemmas, DOI / _2 11

2 12 2 Various Types of Social Dilemma Choices o f Prisoner A Keep silent Make a confession (cooperation) (defection) Choices of Prisoner B Keep silent (cooperation ) 3 years (R) 3 years (R) 1 year (T) 15 years (S) Make a 15 years (S) 10 years (P) confession 1 year (T) 10 years (P) (defection) Fig. 2.1 Example of the game matrix of prisoner s dilemma and its basic structure On the other hand, what happens if my buddy does not make a confession? If I confess, I will be the sidekick and my buddy the ringleader, and I will be imprisoned for only a year. However, if I do not confess, it means that both of us are keeping quiet, which means imprisonment for 3 years. So it is better for me to make a confession. At the end of the day, whether or not my buddy confesses, it is always better for me to confess. Of course, it is not only this prisoner who thinks in this way, if his counterpart is also rational enough, he will also come to the same conclusion that it is better to make a confession. If both make a confession, their term of imprisonment will be 10 years. If both do not confess and keep quiet their term of imprisonment will only be 3 years each. In sum, the prisoner s dilemma game is a game with the following profit structure: if each prisoner gives priority to their own private benefit and thinks rationally about making a confession, the result is a decrease in the private benefit of each. In contrast, if each prisoner does not give priority to their own private benefit and stays quiet, the result is an increase in the private benefit of each. Incidentally, there are four letters R, P, T, and S inserted in Fig. 2.1 to explain the general profit structure of the prisoner s dilemma game. They stand for the weight of the punishment as in R = Reward P = Punishment T = Temptation S = Suckers payoff Having provided the profit structure as such, the game is defined as the prisoner s dilemma game if the following two conditions are met.

3 2.1 Prisoner s Dilemma 13 Condition 1: T < R < P < S Condition 2: 2R < (T + S) Of course, the inequality signs should be opposite, if it expresses not the weight of punishment but the size of profit. Additionally, if you consider the sum of the two prisoners profit the latter Condition 2 shows that the most rational situation is when both keep quiet. 2.2 N-Person Prisoner s Dilemma The social dilemma already explained as Definition A in this book is actually based on the definitions of n-person prisoner s dilemma. It expands the way of thinking of the prisoner s dilemma game to include three or more participants. When Dawes proposed the concept of social dilemma, he defined it as the situation of n-person prisoner s dilemma (Dawes 1980). Thus, the definition of social dilemma in this book which attempts pragmatic solutions is an expansion of the definition given by Dawes. Although the later-mentioned public goods dilemma, commons dilemma, social trap, and social fence are included in the definition of social dilemmas in this book, but not in that of Dawes. In n-person prisoner s dilemma, people must make a choice between cooperation and defection. And the profit gained by choosing a cooperative behavior and a defective behavior changes according to the number of cooperators, namely, how many out of n persons is choosing the cooperative behavior, as shown in Fig However, despite the number of cooperators, you still gain higher profit if you take the defective behavior rather than choosing the cooperative behavior. Benefit Each person s benefit when everyone cooperated =C n Benefit of noncooperator Each person s benefit when everyone cooperated = C n Each person s benefit when everyone did not cooperate = D 0 Benefit of cooperator 0 persons 1 person n-1 persons n persons The number of cooperators Fig. 2.2 Benefit structure of n-person prisoner s dilemma

4 14 2 Various Types of Social Dilemma This is shown in Fig. 2.2 by the way that the profit function of a noncooperator is located higher than that of a cooperator. Incidentally, this is equivalent to Condition 1 in Definition A. However, each person s profit is higher when everyone is the cooperator, compared to when everyone is the noncooperator. This relationship is shown as C n > D 0 in Fig This is equivalent to Condition 2 in Definition B. If these conditions are met, such a social situation is defined as the n- person prisoner s dilemma. In this dilemma, if people aim to increase their private benefit, everyone becomes a noncooperator, according to the above Condition 1. As a result, the level of each person s profit becomes lower than when everyone is choosing the cooperative behavior, according to Condition 2. A situation inclusive of such a dilemma is deemed as n-person prisoner s dilemma. 2.3 Commons Dilemma This is a social dilemma pointed out by Hardin in his essay Tragedy of the Commons published in the magazine Science (Hardin 1968). It illustrates the Tragedy of the Commons as follows; Suppose that a pasture is shared by several shepherds. Each shepherd lives by raising sheep, and can decide the number of sheep in their flock. Now, imagine that there is a rational shepherd who wishes to maximize his profit. He will try to increase the number of sheep as much as possible, since he can obtain a greater amount of milk and wool. Likewise, if all shepherds are rational, they will all try to increase the number of sheep as much as they can. However, the amount of grass provided by the pasture is limited. Therefore, all the sheep will die before the next spring comes. And all shepherds will totally lose their livelihoods. After all, given the limited resources, if everyone is sufficiently self-centered and rational, the sustainability of society as a whole will be lost. Hence the commons dilemma is also known as the resource dilemma. Another name for this dilemma is the take-some game, since it is a game to take some amount from a specific resource. 2.4 Public Goods Dilemma Let us think of a typical example of public goods, such as a bridge or a road, which offer equal convenience to everyone in society. In order to supply such public goods to society, a certain amount of cooperation by people is needed, such as the agreement to pay taxes or use a particular system. Namely, in this case it requires an action to pay some of the cost out of one s own pocket. However, whether or not the public goods are actually supplied, it is more beneficial for each individual not to engage in such cooperative behavior, i.e., not to pay out of one s own pocket. It is because if other people are offering enough of the needed cooperative

5 2.4 Public Goods Dilemma 15 behavior to provide the public goods, your own cooperation or defection does not matter to ensure the supply of the public goods. In other words, each person faces a temptation to free ride on the cooperative behavior of others. Such a situation is also referred to as the the free rider problem of public goods (Olson 1965) which is often discussed as problematic in the field of public economics. If everyone is tempted to free ride, in the end the public goods will not be supplied. However, if each person cooperates for the sake of a certain public consideration, even if some cooperation ends up wasted, the public goods will still be supplied, and everyone will be able to receive benefit. Incidentally, in contrast to the commons dilemma, the public goods dilemma is a game to explore how much of each individual s resources are to be provided to the public. Thus it is also known as a give-some game. 2.5 Social Trap and Social Fence The social trap is a kind of social dilemma proposed by Platt (1973). Its definition is a situation in which conducting a certain behavior (defection) contributes to increasing the private benefit in the short term, but not conducting the behavior (cooperation) contributes to the higher benefit in the long term. The simplest form of social trap is demonstrated by someone on a diet. The person has to make a choice between eating or not eating that cake; they are tempted to increase their private benefit in the present by eating the cake, or to refrain from eating the cake to achieve the long-term goal of the diet. In this case, if you succumb to your desire to eat the cake your attempt to diet will fail. Of course, such a social trap for only a single person is usually not defined as a social dilemma, but for example, the global environment issue mentioned in Sect. 1.3 above can also be defined as a social trap. That is to say, if each person uses their car frequently since they are so convenient, global warming will be the result in the long term. In this case, continuing to use cars without considering the long-term impact can be said to be a form of the social trap. Now, the characteristic of a social trap is that it emphasizes the time axis. That is, in the many dilemmas discussed up to now, such as n-person prisoner s dilemma, it is possible to define cooperation without consideration for future public benefit. However, the social trap defines cooperation as considering the future benefit, as shown in Fig Platt also proposed the social fence as a counterpart to the social trap; in the social fence a certain behavior brings about a higher profit in the long term, but its execution is accompanied with a loss in the short term. For example, it is not much fun to study for an exam, but if you do, you can get a better grade; for an individual such a situation is a social fence. By the same token, in the problem of accepting a road pricing policy that imposes car usage charges, if you are short-term-sighted,

6 16 2 Various Types of Social Dilemma Future Time Scope of benefit considered for cooperation in a social trap/social fence Scope of benefit considered for cooperation in n-person prisoner s dilemma Complete other Present Yourself Social distance Complete other Fig. 2.3 Example of scope of benefit considered in cooperation of social trap/social fence and n- person prisoner s dilemma. Note The scope of benefit shown here is just an example. In n-person prisoner s dilemma, it is also possible to define cooperation considering the time axis. Likewise, in a social trap, it also is possible to define cooperation considering the presence of others in a wider scope. This figure expresses that in n-person prisoner s dilemma, the time axis does not always need to be considered, and in a social trap/social fence, many individuals (or people other than yourself) do not always need to be considered. you will tend to disagree as it incurs a cost. But even taking into account the additional cost, if the policy is accepted, congestion will be mitigated, which brings about long-term benefit. From this point of view, the issue of accepting a road pricing policy can be regarded as a social fence. 2.6 Chicken Dilemma This is a social dilemma with the structure of the chicken game in game theory. The chicken game resembles the prisoner s dilemma game, but the difference is that when both parties choose a defective behavior, each person s profit becomes minimal. In other words, if one follows the definition in Fig. 1.1, the prisoner s dilemma game is in a relationship of Temptation [ Reward [ Punishment [ Sucker s payoff But instead of this relationship, if the following relationship is realized, it is called a chicken game. Temptation [ Reward [ Sucker s payoff [ Punishment Incidentally, this inequality sign is based on defining each variable as a profit. What is shown by this relational expression of profit is that if others are choosing a cooperative behavior, the larger private benefit is provided if you choose a defective

7 2.6 Chicken Dilemma 17 behavior, but if others are choosing the defective behavior, the larger private benefit is provided if you choose the cooperative behavior. Hence the chicken game has a characteristic that a choice to bring about the larger private benefit depends on the action of the counterpart. This is the difference between the prisoner s dilemma in which a larger private benefit is provided if you choose a defective behavior, regardless of the action of the other party. Therefore, in the chicken s dilemma, even for an individual who aims to maximize their self-centered benefit, the expectation of what behavior others choose will have a great impact on one s own behavior. 2.7 Step-Level Dilemma and Volunteer s Dilemma This refers to a type of social dilemma with a structure in which each individual s benefit declines sharply when the ratio of cooperators in society falls beneath a certain level. Many of the commons and public goods dilemmas are step-level dilemmas. For example, let us think of a public goods dilemma where a bridge is to be constructed by donations from residents in a village. If the donations reach the required amount, the bridge will be built. If this happens, all residents can receive the benefit of the bridge. However, if the donations are below the amount, the bridge will not be built, and the village will not benefit from the bridge. Similarly, let us consider road congestion. In general, road congestion occurs when the demand for transportation exceeds the capacity of a certain stretch of road. Naturally if demand is lower than the road capacity, congestion does not occur. If congestion occurs, there will be a sharp increase in traveling time. Even in a section of road which you can drive through in just 5 min before congestion, once the road is congested, it may take more than 20, or even 30 min to escape the traffic jam. In this way, the step-level dilemma has a profit structure in which the profit received by an individual changes rapidly and discretely, such as a bridge can or cannot be constructed, or congestion does or does not occur. The volunteer s dilemma is a special type of the step-level dilemma (Diekmann 1985). It is a dilemma with a profit structure in which each individual s profit changes rapidly depending on whether there is one cooperator or not. Many helping behaviors have a step-level dilemma structure. The most representative example is whether someone helps a person who has collapsed in a crowded place. In this case, only one individual needs to offer help, but if no one steps forward, the person may die. Other cases are whether someone cleans a public area such as a park or a school research lab, or who is taking the leadership in organizing a festival or a sports event. They can all be regarded as the volunteer s dilemma, since they are all situations in which if there is just one volunteer, the public benefit increases greatly.

8 18 2 Various Types of Social Dilemma References Dawes, R. M. (1980). Social dilemmas. Annual Review of Psychology, 31, Diekmann, A. (1985). Volunteer s dilemma. Journal of conflict resolution, 29, Hardin, G. (1968). The tragedy of the commons. Science, 162, Komorita, S. S., & Parks, C. D. (1994). Social dilemmas. Madison, WI: Brown and Benchmark. Olson, M. (1965). The logic of collective action. Cambridge, MA: Harvard University Press. Platt, J. (1973). Social traps. American Psychologist, 28, Yamagishi, T. (1989). Main theoretical approaches of social dilemma study. Japanese Psychological Review, 32(3), (in Japanese with English abstract).

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