An Evolutionary Approach to Norms

Norms are part of what glues groups and societies together -- informal agreements about behavior that are enforced by populations through social disapproval rather than by laws and law enforcement. Saying "excuse me" when bumping into someone, or queuing up at grocery stores are just two of many examples. Research into behaviors using the prisoner's dilemma game, pioneered by Robert Axelrod, has revealed that people will sacrifice money to punish people who break norms in such games. ("altruistic punishment may be the glue that holds society together.") Axelrod notes that cooperation depends not only on punishment of norm breakers, but also on punishment of those who fail to punish norm breakers!

Title:  An Evolutionary Approach to Norms
Source:  Robert Axelrod, The Complexity of Cooperation, Princeton University Press,
Pub:  American Political Science Review 80, No. 41095-1111
Publication Date:  1997
URL:  http://pscs.physics.lsa.umich.edu/Software/ComplexCoop.html

Authors:

Axelrod, Robert



Findings:

• Norms can emerge in competitive situations when players can observe each other and imitate the strategies of successful players.

• N-person Prisoner's Dilemma games can't be resolved with simple  reciprocity without enabling cooperators to also punish defectors.

• Norms can emerge and grow stable if metanorms establish a  willingness to not only punish violators but also those who fail to  punish violators.

• Norms likely emerge from behaviors that signal others to reward  individuals (reputation), and spread through both imitation as well as  punishment of violators.

• "There may be some useful cooperative norms that could be hurried along with relatively modest interventions."

One Sentence:

Exploration of games in which  punishment is possible and cheating is not automatically detected  reveals that norms can emerge and stabilize only if those who fail to  punish violators are also punished.

One Paragraph:

The  decrease in punishment of those who failed to punish violators may have  played a part in the sudden collapse of communism, and Granovetter  noted that riots can have tipping points in which "a slight change in  the willingness of a few people to act first can get the ball rolling."  Axelrod defines norms thus: "A norm exists in a given social setting to  the extent that individuals usually act in a certain way and are often  punished when seen not to be acting in this way." Therefore, norms are a  matter of degree, not all or nothing.  "By linking vengefulness against  nonpunishers with vengefulness against defectors, the metanorm provides  a mechanism by which the norm against defection becomes self-policing."  Reputation plays a role because defection is not only a means for a  defector to harvest a payoff, but a signal that can be used be others:  "a norm is likely to originate in a type of behavior that signals things  about individuals that will lead others to reward them." The  observation from norms-game trials that norms can sometimes establish  themselves quickly led Axelrod to conclude that "there may be some  useful cooperative norms that could be hurried along with relatively  modest interventions."