Public Goods Game

Basic Procedure

Each participant receives an initial "endowment" of 20 each round.
During each round, you may contribute up between 0 and all of the endowment you receive that round to the "public good"
We then total up all the contributions and multiple by 1.5
Then we divide this up among ALL players (without regard to how much each contributed).

Three groups

In group 1, the game is played "confidentially," that is, the players do not find out what the other participants have done in each round, only the aggregate results.

In group 2, the group members have to announce what their contributions were.

Group 3 is like group 2 except participants have an opportunity to punish any group members whose behavior they did not appreciate. Punishment costs $1 for each one imposed. The cost to the recipient of the punishment is to forfeit 10% of the return from the public kitty that they would have received.

VARIATIONS: One group tight knit. One group puts someone in charge?

Your grade for the exercise will be based on the size of your balance after ten rounds as follows

Balance Grade
270-300 A+
240-269 A
210-239 A-
180-209 B+
150-179 B
120-149 B-
90-119 C+
60-89 C
30-59 D
<30 F


Write a short (250 words) essay describing the game and what happened, and offer suggestions for how a group could maximize it's collective outcome. The description can be very brief noting that a group of students played a standard "public goods game" Why do you think people who did not contribute maximally did not? Or, why do you think people contributed more than they "had to"?

Your essay should have a title and a works cited section using standard citation format. Page format shown below.

Here's a paragraph from Gintis, et al. (2003)

The public goods game has been analyzed in a series of papers by the social psychologist Yamagishi (1986, 1988), by the political scientist Ostrom, Walker, and Gardner (1992), and by economists Fehr and Ga¨chter (Fehr & Gachter, 2000, 2002; Ga¨chter & Fehr, 1999). These researchers uniformly found the groups exhibit a much higher rate of cooperation than can be expected assuming the standard economic model of the self-interested actor, and this is especially the case when subjects are given the option of incurring a cost to themselves in order to punish free riders.

You can simply mention the public goods game and cite Gintis et al. and Yamagishi 1986:

  • Gintis, Herbert, Samuel Bowles, Robert Boyd, and Ernst Fehr. 2003. "Explaining altruistic behavior in humans," Evolution and Human Behavior 24, 153–172.
  • Yamagishi, T. 1986. "The provision of a sanctioning system as a public good." Journal of Personality and Social Psychology, 51, 110–116.

Page Format

Title of Essay
Mills College soc112
25 January 2012

(249 words)

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed placerat imperdiet mattis. Pellentesque eget nisi risus. Nulla dignissim neque semper purus adipiscing et adipiscing lectus laoreet. Aliquam adipiscing nisl quis augue tempor mattis. Etiam malesuada turpis sed orci fringilla nec lobortis velit venenatis. Nulla molestie, est id posuere gravida, justo orci lacinia mi, eget mollis sem felis id leo. Fusce eget sem ut lacus pharetra tempor. Nulla in enim enim, nec rutrum felis. Nam eu nisl sem. Maecenas congue sem non neque auctor molestie. Pellentesque mattis dictum nunc, at elementum libero tristique sit amet.

Mauris venenatis vulputate enim, vitae sollicitudin diam porttitor eu. Vivamus sed arcu sed neque aliquet venenatis. In hac habitasse platea dictumst. Morbi feugiat tincidunt eros at vestibulum. Fusce massa lectus, porttitor eget sodales nec, adipiscing vulputate eros. In malesuada sem vitae ligula mollis id molestie ipsum suscipit. Ut pellentesque elit sit amet arcu molestie quis pellentesque lorem interdum. Fusce interdum interdum dapibus. Sed ultricies neque rutrum nibh sollicitudin congue. Curabitur malesuada consectetur dui, et commodo nunc vestibulum eget. Vestibulum vitae turpis tellus, in hendrerit mi. In enim sem, congue non porttitor nec, elementum ut metus. Nunc et dui pretium leo gravida porta ac vel mi.

Sed ullamcorper quam vitae tellus cursus posuere. Nunc suscipit tellus at augue vestibulum a dapibus nulla sodales. Proin id vestibulum risus. t, nec facilisis erat eros sit amet lorem. Sed quis purus odio, eget aliquam orci. Vivamus sagittis orci in ligula feugiat sed dapibus dolor posuere. Aliquam ac tincidunt velit.

Works Cited

AuthorLname, Fname. Year. "Article Title." Journal Name volume, number: pages.
AuthorLname, Fname. Year. Book Title. City: Publisher.

File nameFile typeSize
public-goods-game-handout.pdfPDF document70.05 kBInfo
public goods game tally sheet.docxNo description37.78 kBInfo
public goods game tally sheet.pdfPDF document419.63 kBInfo
public-goods-game.xlsxZip archive data17.04 kBInfo