K-12 Teaching and Learning From the UNC School of Education


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Related pages

  • Areas of philosophy: This page introduces the various areas of philosophical thought, and links out to our (related) lesson plans.
  • Lesson plans on the web: This page provides links to a variety of philosophical lesson plans for high school teachers.

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Learning outcomes

Students will:

  • explain why what is in their own best interest may not be the best decision for the community.
  • explain what “goodness” means.

Teacher planning

Time required

45-60 minutes

Materials needed

  • Candy
  • Rules sheet to project

Background information

The candy game activity is based on “The Prisoner’s Dilemma” which is described below. Teachers may wish to go over this with older or more advanced students.

The Prisoner’s Dilemma

Teachers may wish to discuss “The Prisoner’s Dilemma” with older students.

Suppose there were two people in prison being prosecuted for a crime committed together. The police interviewed the prisoners separately and asked them to snitch on each other. Each prisoner has two options—betraying the other prisoner (opposing) or staying silent (cooperating). If one of them betrays while the other one stays silent, the betrayer goes free while the other person serves three years in prison. If neither of them betrays, then they both serve one year in prison on a lesser charge. But, if they both betray, then they both serve two years in prison (slightly reduced sentences for helping police).

The dilemma arises because it is in each individual’s best interest to oppose. Regardless of what the other person does, you will minimize your prison sentence if you oppose. This results in an equilibrium where both people betray each other. However, it would be better for them collectively if they both co-operated as this leads to the shortest amount of combined prison time.

Here are the different scenarios that could happen:

  1. Prisoner A Cooperates Prisoner B opposes = Prisoner A serves three years and Prisoner B goes free.
  2. Both Prisoner A and B cooperate = Each serves 1 year.
  3. Both Prisoner A and B betray= Each serves 2 years.

This thought experiment presents a number of important philosophical and social issues: primarily, the conflict between self-interest and community interest. Oftentimes what is best for an individual is collectively harmful (for example, group assignments). If a student believes his peers will work hard on an assignment it would be in his best interest to slack off (according to the conception of self-interest we are working with here). However, if his peers did the same calculation and slacked off then the assignment wouldn’t get finished, nor would it be very good. Secondly, it brings up the nature of obligations towards individuals and communities. To what extent are we obligated to treat others fairly by cooperating and what circumstances influence this decision (such as our relationship with them)?

In the game below, we modified the payoffs by giving candy, instead of prison time. The logic works the same except now you want more candy, rather than less prison time.


Main Activity: Candy Game

Candy Game Rules

You have been placed in groups of four. Within each group of four, there are two pairs. One pair will be the “watcher” pair. The other pair will be the “player” pair.

  1. The two members of the player pair will stand back to back. They may not consult each other.
  2. A member of the “watcher” pair will write down the other students’ names. The other member of the watcher pair will count to three.
  3. On the count of three, each member of the player pair will put his or her thumb up or down. Thumbs up means you want to cooperate with the other player. Thumbs down means you want to oppose the other player.
    1. If both students put their thumbs up then they each get two pieces of candy.
    2. If both students put their thumbs down then they each get one piece of candy.
    3. If one student puts their thumbs down, while the other puts his/hers up, then the one who put his/her thumb down gets three pieces of candy while the other gets none.
  4. One of the members of the “watcher” pair will write “up” or “down” under the players’ names, indicating which way they put their thumb.
  5. The two pairs will then switch roles and repeat steps one through four.
  6. After both pairs have had the opportunity to be both watchers and players, bring the paper to the teacher who will distribute the candy.


  1. Once every pair has done this ask the students why they chose to cooperate or oppose.

    1. If they chose to cooperate ask them why they chose this if they wanted to get the most candy.
    2. Most likely an explanation of why this is true will be needed. Show the class why opposing is the rational decision to get the most candy for yourself.
      1. If you put your thumb down, you will get candy no matter what (three pieces if your partner puts their thumb up, two if you you both put your thumb down). If you put your thumb up, you will only get candy if your partner also puts their thumb up.
  2. Ask the class if they felt obligated to cooperate for some moral reason, and, if so, why?
  3. Pose the question, “Does doing the right thing tend to go against your self-interest?”
  4. Ask the students what obligations they have toward communities and whether cooperating was the right choice because it led to maximum community benefits.
    1. Does this change if you have or have not made an explicit deal or commitment with the community?

Additional discussion questions: for small groups or the entire class

  1. Moral laws—Ask students if they feel it is not morally permissible to betray their community or partner no matter the circumstances.
  2. Does the other person’s history matter?—Ask students: if they played again with the same partner and if in the previous iteration they were betrayed would this mean they have a reason to change their choice? What if the first time they simply suspected their partner would not cooperate; is this a strong enough justification to betray them?
  3. Is this like the real world?—It might be interesting to ask the students if they think this sort of trade off is like real situations (i.e., helping or mooching off of their families) or if it is unlike the real world. Does practicing morality in everyday life tend to involve making choices against your own narrow self-interest?

Concluding Activity: Ring of Gyges

  1. Bring students into a circle and introduce the Ring of Gyges:

    1. Suppose there was a ring that you could wear and which made you invisible. While you’re invisible no one notices your absence or senses if you’re around them. You are free to do as you wish; what would you do?
    2. Ask for a few volunteers to share their thoughts.
  2. Ask the students, “Would you act differently if you were invisible, and if so what would you do?”
    1. Expect answers to be activities often frowned upon in society.
    2. Don’t spend too much time with students describing what they would do; this should just be for fun.
  3. Ask why students would act differently when invisible than in their normal life?
  4. If it doesn’t come up naturally, mention one reason people might act differently is because when we are visible we can be caught.
  5. Ask the question, “Does this mean that the only reason people are good is because they are afraid of getting caught for acting bad?” Facilitate student responses.
  6. Ask the students if people are only good because they think they are getting the benefits of having a good reputation in society. Would someone be good if they were wearing the ring?
  7. Finally, have the students give their opinions and reasoning on what “goodness” is and what it means to be a good person.
    1. Does this fit with the previous discussion on why people make decisions that are not in their own best interest?
  8. As a final activity, ask students to write an explanation of goodness. What does goodness mean to them? What is the difference between individual vs. communal good? You should tell students how long you expect their explanation to be.

Additional questions:

  1. Is submitting to your desires while invisible itself an injustice (what about when you’re not invisible)? —Plato thought so and argued that a truly rational and developed person will maintain his/her composure even if he/she could do anything with no consequences.
  2. Is being good an end or a means to an end?—In other words, should you, or are you, good because being good is “good?” Or, alternatively, are you good because being good allows you to be happy and gain recognition?


Teachers should assess that students are participating in activities and discussions.


A potential follow up activity would be a discussion of Aristotle’s and John Stuart Mill’s description of the good. Aristotle thought the good was being the best you could be at what you pursued. For example, a student is good if the student dedicates herself to her studies to be the best possible student. Mill thought the good is that which maximizes happiness, or utility. The good action is one that brings the community the most amount of happiness. Note, this doesn’t necessarily mean doing what makes you personally happy right now because certain things might make others unhappy or might have long-term side effects. All of these things have to be considered in determining the good action.

Some suggested activities would be to have students read stories which emphasize one of these two theories. Have the students talk about the story and whether they think it is a good idea. Introduce the second theory as a potential alternative and ask if this is preferable. Lastly, ask the students to come up with their own description of goodness and have a discussion on how it is similar and different from other theories.


Supplemental information

This lesson plan was initially developed by Peter Warrington and Baker Renneckar, UNC students enrolled in Philosophy 592 (Pre-College Philosophy) taught by Dr. Michael Burroughs in Spring 2013.

  • Common Core State Standards
    • English Language Arts (2010)
      • Speaking & Listening

        • Grade 6
          • 6.SL.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 6 topics, texts, and issues, building on others’ ideas and expressing their own clearly. 6.SL.1.1 Come to discussions...
        • Grade 7
          • 7.SL.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 7 topics, texts, and issues, building on others’ ideas and expressing their own clearly. 7.SL.1.1 Come to discussions...