Reciprocal Altruism
the trading of altruistic acts in which the benefit is larger than the cost so that over time participants enjoy a net gain.
- Delay between donation cost and receipt of benefit separates mutualism from reciprocal altruism.
- Delay allows for the possibility of cheating, thus cheaters must be detected and excluded
- A sufficient number of interactions must occur to provide a net benefit to participants. Note that in many instances, the net benefit will increase with the number of exchanges. Thus, a large number of interactions favors reciprocity.