27 Blind Mice

Posted August 31, 2016 by turtle
Three blind mice image from lehighvalleyramblings.blogspot.com

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Project GUTS (excerpted from Adventures in Modeling (Colella, Klopfer, and Resnick).

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Musicians in an orchestra take cues from the conductor as the tempo changes; students pass notes to each other during history class; football players simultaneously initiate the play as the quarterback calls “hike.” In any multi-agent system, members of the system communicate with one another. Even in systems comprised of nonhuman entities, objects exchange information. For instance, billiard balls “communicate” information about their velocity and direction as they collide.

Thought of broadly, “communication” can take many forms. Sometimes communication is mediated by a central individual like the conductor or quarterback. Other times, individual members communicate directly with one another, like the students passing notes. This Activity lets you explore the differences between and the consequences of global communication, where every group member has access to information, and local communication, where information exchange is limited to personal communication channels (which can be further constrained by the mode of communication).

27 Blind Mice is a compilation of three distinct games designed to engage participants in thinking about different types of communication strategies. In each game, the goal is the same, but the mode of information exchange that participants can use to achieve that goal is very different. In Part One, the participants usually employ centralized or global strategies, in which a small number of people take the lead and organize the others. In the latter two games, the participants’ strategies shift to more decentralized or local methods, in which everyone gathers information only from people in their immediate neighborhood.


  • Experience the dramatic difference between local and global communication.
  • Explore the process of group formation.
  • Think about the effects of different ways to access information.


MATERIALS NEEDED Post-it notes Pencils Blindfolds

Ask each participant to pick a random integer from 1 to 5 and write it on a Post-It note. Tell everyone to organize into like-numbered groups (i.e., all of the 1s together, all of the 2s together, and so on). Do not tell them how to get into their groups. After the groups are formed, ask them to reflect on how they achieved their groupings. 

  • Did some people act as leaders, shouting out the numbers? 
  • Did others move quietly to the “correct” part of the room? 
  • If there were leaders, how were they chosen?

Also, look around and observe the size of the groups. Is the distribution of 1s equal to that of 2s? 3s? and so on? Is this the expected result?


Ask participants to write a new random number on their Post-Its. Again, have everyone organize themselves into like-numbered groups—but this time, explain that they are not allowed to talk. The only way participants are allowed to communicate is by showing their Post-It notes to one another. They are not allowed to communicate in any other way: No raising fingers, no stomping feet. When the groups have formed, ask participants to compare the two activities. 

  • What kinds of strategies did individuals and groups employ to find people with the same number? 
  • Which of these strategies was most successful? 
  • Are there any individuals who did not find their group? Are they alone or with others? If a small group of 3s gets together but does not ever locate the other group of 3s, a local optimum results because the entire group of 3s never fully convenes.

People tend to employ very different communication strategies in Game Two. 

  • Which game did people find easier—the one with global information or the one with more restricted, local information? 
  • Which game was more fun? Why? 
  • What kinds of systems in the natural world include strategies like those used by participants in the first game? Are there any systems that include strategies employed in the second game?


Ask participants to choose another number from 1 to 5 and write it down. The goal is the same as in the previous games: To form like-numbered groups. But this time, you will give the participants blindfolds so that they cannot see one another during the game. Explain that participants can communicate with whispers but not loud talking. Note: Make sure that people who feel uncomfortable being blindfolded do not feel obligated to participate. These people can act as monitors, making sure that other participants do not wander into dangerous situations.

When everyone has chosen a number, ask them to put on their blindfolds. When everyone is ready, have them find the people in their group. When the groups have formed (but before people remove their blindfolds), ask them to reflect on their activity.  

  • Did it take longer for groups to form?
  • How did people feel when they found a like-numbered individual? After they take off their blindfolds, ask them to articulate what kinds of strategies they used in this third game.
  • How did their strategies differ from the first and second games?
  • Are the group patterns that result from the third game different in any way from those in the first two games?


Asking participants to divide into five groups works well if the total group size is between 20 and 30. If your group is significantly larger or smaller, you may want to adjust the number of different small groups accordingly.

Depending on the situation, creatures might use local or global communication strategies. StarLogo models generally incorporate behaviors that are based on local interactions. It might be helpful to think of the turtles in StarLogo as blindfolded, whispering people. Turtles are designed to react to creatures and objects in their immediate local environment. 27 Blind Mice should give participants a feel for the dramatic effects of local communication.

The 27 Blind Mice Activities were first developed by Mitchel Resnick and Uri Wilensky. For an extended description of these and other decentralized role-playing activities, see Resnick & Wilensky (1998).

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