Stag hunt

The stag hunt problem originated with philosopher Jean-Jacques Rousseau in his Discourse on Inequality.

In the most common account of this dilemma, which is quite different from Rousseau's, two hunters must decide separately, and without the other knowing, whether to hunt a stag or a hare.

This situation is often seen as a useful analogy for many kinds of social cooperation, such as international agreements on climate change.

No payoffs (that satisfy the above conditions including risk dominance) can generate a mixed strategy equilibrium where Stag is played with a probability higher than one half.

The best response correspondences are pictured here.Although most authors focus on the prisoner's dilemma as the game that best represents the problem of social cooperation, some authors believe that the stag hunt represents an equally (or more) interesting context in which to study cooperation and its problems (for an overview see Skyrms 2004).

In biology many circumstances that have been described as prisoner's dilemma might also be interpreted as a stag hunt, depending on how fitness is calculated.

It is also the case that some human interactions that seem like prisoner's dilemmas may in fact be stag hunts.

In times of stress, individual unicellular protists will aggregate to form one large body.

Orcas cooperatively corral large schools of fish to the surface and stun them by hitting them with their tails.

Author James Cambias describes a solution to the game as the basis for an extraterrestrial civilization in his 2014 science fiction book A Darkling Sea.

[4] Robert Aumann proposed: "Let us now change the scenario by permitting pre-play communication.

Weiss and Agassi wrote about this argument: "This we deem somewhat incorrect since it is an oversight of the agreement that may change the mutual expectations of players that the result of the game depends on... Aumann’s assertion that there is no a priori reason to expect agreement to lead to cooperation requires completion; at times, but only at times, there is a posteriori reason for that... How a given player will behave in a given game, thus, depends on the culture within which the game takes place".