The dynamics of indirect reciprocity

Area of Science:

• Evolutionary game theory
• Social behavior analysis
• Game theory modeling

Background:

• Moral systems are theorized to originate from indirect reciprocity.
• Image scoring is a mechanism proposed to facilitate indirect reciprocity.

Purpose of the Study:

• To analyze a model of indirect reciprocity using image scoring.
• To determine conditions for the stability of altruism against defection.

Main Methods:

• Analysis of a simple indirect reciprocity model based on image scoring.
• Examination of a dynamical system with discriminating and indiscriminate altruists.
• Inclusion of incomplete information in the model.

Main Results:

• Discriminating altruism demonstrates resistance to defection.
• Indiscriminate altruism can invade via random drift, creating complex dynamics.
• Defector invasion is limited when attempts are sufficiently rare under incomplete information.

Conclusions:

• Indirect reciprocity via image scoring can support altruistic behavior.
• The stability of altruism is influenced by factors beyond genetic relatedness, such as acquaintanceship.