June 19, 2012
Responsible punishment does not initially seem to have any advantage for the person being punished and therefore does not fulfil the requirement for the evolution of such behaviour. To resolve this problem, Hilbe and Traulsen developed a two-stage mathematical model. In the first stage, the players can be either cooperative or uncooperative. Based on this, they must decide in the second stage whether or not they will punish others for previous behaviour. This shows that cooperative behaviour and justified sanctions are only carried through if the interactions can be observed by others.
“The decision by someone to punish others then affects not only the short-term relative advantages of the players, but also their reputation”, says Arne Traulsen.
A subject’s own reputation seems then to have a very high value, as individuals punish unfair behaviour, even when they must reckon with resistance. “We are prepared to pay a high price to maintain our reputation. The suspicion that someone is watching us is enough to increase our willingness to cooperate”, explains Christian Hilbe.
Punishment is therefore primarily worthwhile if it is used responsibly. Sanctions not only have the purpose of punishing uncooperative behaviour, but also work as a signal to outsiders. Only through responsible sanctions can the willingness to cooperate in the population increase. The tendency shown prior to this, to punish unfair behaviour, would thus be an advantage in the long term and balance out the costs incurred. The ability of humans to collect information through others, pass it on and so build up a reputation consequently seems one of the fundamental reasons for the particularly pronounced willingness to cooperate among people.