COMMUTER BRIDGE

Basic Data

Introduction

COMMUTER BRIDGE is a game based on the Braess paradox (1968). COMMUTER BRIDGE allows the participation of large groups in which participants make their choices individually rather than in groups. For this reason, an activity based on the dynamics of the Braess paradox is particularly suitable to describe the collective damaging effects of social dilemmas (Kollock, 1998), and the main constraints of situation of tacit negotiation (Thompson, 2012). The Braess paradox is defined as the counter-intuitive phenomenon in which the introduction of a route in a traffic network leads to a traffic increase rather than a decrease (Braess, 1968). On Earth Day in 1990 New York’s 42nd Street was closed for a parade (Kolata, 1990) and in 1999, due to maintenance, they shut down one of the three main traffic tunnels in South Korea’s capital city (Vidal, 2006). Although both routes were heavily used for traffic, that traffic flows improved in both cases. For further details the reader may refer to Braess (1968), Rapoport, Kugler, Dugar, and Gisches (2009), or Dal Forno and Merlone (2013).

The Activity

In this activity, participants are asked to play the role of commuters who must each day choose among different routes to get from their home to their office. Each route has different travel times and the goal of the activity is to reach the OFFICE in the shortest possible time.

The activity is divided in two phases:

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Figure 1.

Basic network.

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Figure 2.

Augmented network.

COMMUTER BRIDGE can be used in courses on social dilemmas and tacit negotiation. It can be interesting to use this simulation after participants have experienced a two-person prisoner’s dilemma. In this way, participants can better understand the different dynamics and constraints underlined by large-group dilemmas.

Activities requiring two participants are the most common among negotiation courses. Among these types of exercises, we can find those based on two-person prisoner’s dilemmas. Although for these activities it is possible to consider two groups rather than two persons, the dynamics remains related to the two-person interaction. Background information about this activity and its educational benefits of using can be found in Merlone and Romano (in press). Then we provide also some case studies which can be presented when using this activity in classroom.

This ready-to-use simulation offers a social dilemma exercise that both works with several participants and is manageable enough to be used with little preparation. The Facilitator guide includes a completed example, not be shown to participants.

Facilitator’s Guide

The activity is played in 16 turns divided into two phases: eight turns in the basic network phase and eight turns in the augmented network phase. The simulation can be played by different sized groups. Required materials consist of a set of answer cards, a worksheet to compute the payoffs (Appendix D and E), and a whiteboard or blackboard to report results.

Materials

Set of answer cards

The set of answer cards consists of 16 cards on which, at each turn, participants write the route they have selected (the cards are ready to be printed in Appendix B).

Worksheet to compute payoffs (Appendix A)

A worksheet to compute payoff helps the facilitator manage the game

Whiteboard or blackboard

The basic network, the augmented network and the travel time of participants are written on a whiteboard or blackboard. An example of the payoff table is shown in Appendix A and in the completed example.

Operation instructions

Distribute the participants instructions for Phase 1 (Appendix A), then draw the basic network on a whiteboard. Make sure that each participant has understood the instructions. Several examples can be provided for a better understanding of the game.

Read aloud Phase 1 Participants’ instructions

Distribute the set of answer cards.

Participants accumulate points by reducing the time taken to reach OFFICE. To provide some external motivation, points can either give participants extra class credits or be used to win a prize.

Explain to the participants how their results will depend on both their decisions and those made by the other participants.

Phase 1: Basic network

Participants play the basic network phase for eight silent rounds: they cannot talk during the exercise. It can be useful to have a practice round or two to help the participants understand the game mechanics.

For each of eight turns, the participants simultaneously express their choice on separate cards.

At the end of each turn, the cards are collected by the Facilitator, and payoffs for each routes are announced and written on the whiteboard. To speed up the game management, ask one person to collect the cards, and another to enter the data into the worksheet. Do not erase the outcome matrix. It will be used to explain the dynamics of the game during Debriefing. Never answer questions asking advice on how to make decisions or choices during the game play.

Phase 2: Augmented network

The augmented network works like the basic network, with the addition of one route. Distribute the participants instructions for phase 2 (Appendix C).

A few practice rounds can again be run to help participants understand the game mechanics. No communication among participants is allowed. As a variant, participants may be given 10/20 minutes to discuss and negotiate a possible strategy. According to Susskind (2004), multiparty negotiations have several problems, such as the presence of subgroups, the discussion of multiple issues, and agreement on decision-making rules. If some participants ask questions that can affect the dynamics of the game, they should be postponed to the debriefing session. Although in this phase the interaction is supposed to be silent, often participants may comment and express their frustration. Unless these comments disrupt the interaction dynamics, they can be tolerated. Figures 3, 4 and 5 provide a completed example with 30 participants. Participants’ choices for phases 1 and 2 are reported in Figures 3 and 4 respectively and allow computing travel times. These are summarized in the payoff tables reported in Figure 5.

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Figure 3.

Worksheet tables for the worked example with 30 participants (phase 1).

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Figure 4.

Worksheet tables for the worked example with 30 participants (phase 2).

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Figure 5.

Payoff tables for the completed example with 30 participants.

Debriefing Section

Begin the debriefing with questions on personal sensations, emotions and thoughts experienced during the game. Possible questions include:

Always give the participants the opportunity to express feelings or raise questions. The Facilitator can underline the point that the poor performance of the collectivity is typical of negotiation games, and it does not reflect on their talents or competence. The facilitator may show this short video that summarize the dynamics of the Braess Paradox: https://www.youtube.com/watch?v=sTQAu9TW4jM

Once the Debriefing is over, it is possible to explain tacit negotiation, to present the main features of social dilemmas, and to show the applications to real world negotiations. The meaning of the Braess paradox can now be discussed, and clarified, using the game experience.

Results

In this section we present some patterns of behavior we observed in three different groups. This activity has been utilized both as classroom activity and in corporate training programs.

In all the examples we provide, it may be observed the trial and error process to find an equilibrium when only two choices are available. In the cases presented in Figure 6 the group was not given any time to discuss at the beginning of Phase 2 when the new link was introduced. In the cases presented in Figures 7 and 8 the participants where given about 20 minutes to discuss at the beginning of Phase 2.

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Figure 6.

University of Torino Biella Campus 2012 quantitative methods for business course 37 participants.

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Figure 7.

Universitad de Chile 2013 negotiation course 29 participants.

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Figure 8.

University of Torino 2014 conflict management and negotiation 10 participants.

Conclusion

In our experience, participants reaction has always been positive, as this game allows the experience of the complex dynamics of large group negotiation. In our experience, this activity, especially when run with large groups may be an occasion to simulate the main dynamics of social dilemmas and difficulties of managing group interactions (Susskind, 2004). In particular, since it is particularly difficult to avoid recovering from congestion (if only a few participants don’t take the bridge their travel time would be worse compared to the others), this allows to better underline social dilemmas problems and traps. Then, the capacity to make possible an interaction among several participants, the short time required and the focus on constraints of social dilemmas are the main strong points of this ready-to-use-game. This tool can increase participants’ skill, awareness, and competence against the negative consequences of competition. Finally, it shows how failing to find an enforceable agreement among the parties means leaving money on the table. COMMUTER BRIDGE is a negotiation exercise for large groups, and provides an activity suitable when the class size is large and few teaching assistants are available (Patton, 1995). In the future, we plan to create more social dilemma games which can be run with groups of different sizes.