Field of Science

Freedom and the Public Goods

Last post, I used the example of a protest against peanut allergy-related procedures to explore how the American conception of "rights" may be changing. In particular, I suggested that ideas of common or collective good were being displaced by an increasingly narrow and selfish definition of individual liberty.

A few friends pointed out that I may have unfairly maligned libertarians, anarchists, and others wary of government power.  These people aren't necessarily opposed to volunteerism or helping others; they just don't want to be coerced into doing so (or have their money taken for these purposes).  

This is a fair point.  However, it doesn't make me feel much better about the "leave me alone" political philosophy.  I don't think this philosophy will ever be up to solving our common challenges.  To illustrate why, I'd like to bring in a concept from game theory.

The Public Goods Game represents situations in which there is a common resource ("public good") that benefits all members of a group.  The public good might be a clean kitchen, a functioning electrical grid, or a healthy environment.  This good cannot be maintained without contributions from some group members.  Contributions can be in the form of doing something (washing dishes, working in the community garden, donating to NPR) or not doing something (not littering in a public park, not overfishing a lake).

The dilemma is this: everyone benefits from the public good, but contributions are voluntary.  The public goods game has no built-in incentive to contribute, beyond the desire to make things better for everyone.  So "free-riders" can benefit from others' contributions without contributing anything themselves. 

Both theory and experiment predict that cooperation cannot be sustained in such a game.  A typical experimental result looks like this:

Horizontal axis is time (number of game rounds)  SOURCE: Fehr and Gaechter (2000)

Contributions decline over time to virtually nothing. This is not because the participants are inherently selfish.  Indeed, at the start of the game, many people are inclined to contribute.  However, they realize at some point that others are exploiting their generosity.  Not wanting the benefits of their hard work to reward those who don't contribute, people eventually stop contributing altogether.  This unfortunate outcome has a name: the Tragedy of the Commons

Economists and social scientists have identified a few mechanisms that can reverse this tragedy.  If the participants know each other, and also interact in settings aside from the game, then concern for one's reputation can motivate people to contribute (Milinski et al. 2002, Rand et al. 2009).  This helps explain why co-ops can be successful: everyone knows each other.  They can reward or punish others based on their contributions to cooking, cleaning, and other tasks. 

But what about global challenges like climate change, environmental conservation, and sustainable use of resources?  These involve billions of players across the globe, and there are strong financial incentives to exploit the public good for individual gain.  Furthermore, it can be difficult to trace problems like pollution or overfishing to the individuals or companies responsible.  How these large-scale challenges be solved?

Research has identified only one answer. If the game is too large and complex for individual interactions to maintain cooperation, the solution is for the participants to invest in institutions (Gureck et al., 2006; Sigmund et al., 2010).  These institutions must have the power to investigate the actions of individuals, and reward or punish them based on their contributions. In other words, a social contract is needed, together with institutions to enforce it.

Of course, powerful institutions have inherent potential for corruption and abuse.  This is what worries libertarians and anarchists.  I share that concern.  But the solution, in my view, is to build in democratic checks, so that these institutions are as responsive as possible to the people they serve.

It's hardly a perfect solution.  Institutions can become entangled with those they should regulate.  Democratic checks can be co-opted. 

But to solve the largest problems that face humanity, we can't count on good will and personal responsibility alone.


Ernst Fehr, & Simon Gaechter (2000). Cooperation and Punishment in Public Goods Experiments American Economic Review, 90 (4)

Özgür Gürerk, Bernd Irlenbusch, & Bettina Rockenbach (2006). The Competitive Advantage of Sanctioning Institutions Science, 312 (5770), 108-111 DOI: 10.1126/science.1123633

Milinski, M., Semmann, D., & Krambeck, H. (2002). Reputation helps solve the ‘tragedy of the commons’ Nature, 415 (6870), 424-426 DOI: 10.1038/415424a

Rand, D., Dreber, A., Ellingsen, T., Fudenberg, D., & Nowak, M. (2009). Positive Interactions Promote Public Cooperation Science, 325 (5945), 1272-1275 DOI: 10.1126/science.1177418

Sigmund, K., De Silva, H., Traulsen, A., & Hauert, C. (2010). Social learning promotes institutions for governing the commons Nature, 466 (7308), 861-863 DOI: 10.1038/nature09203