Create Groups and Agents
Ceate 25 groups with size 20.
Assigning Traits: Each agent is assigned one of three
traits; Grabbing, Sharing and Punishing.
(For the first property rights revolution simulation):
Each agent is one of Bourgeois, Sharer, or Punisher.
Group size is kept constant.
Groups are placed on torus and have 4
neighbors on North, South, East and West sites.
The Game within Groups (Repeat 5 times)
Pairing: In each round, each agent is randomly paired to
another agent of his/or her group, called a partner.
Playing Games: Agents play the punishment game with their
partner and get payoffs according to the payoff structure given in the
(For the first property rights revolution simulation): The
game is played with Punisher, Sharer and Bourgeois.
With 2nd-Order Punishment
After a punisher fights
with a grabber, punishers also punish sharers each sharer bears the cost
–0.3 and each punisher shares the cost –0.15 (i.e. each punisher
gets –0.15/m, where m is the number of punishers in a
In each generation (after playing the punishment game 5
times within each group), groups are involved in a conflict with a randomly chosen neighbor.
The group with the higher average
payoff wins the conflict.
Resource Transfer from Loser to
Winner: The winners of a conflict seize some of the resources of the
losing group. We model this by reducing payoffs to all members of the
losing group and adding the same amount of payoff to all members of the
wining group. Resource Transfer is assumed to be 3.
Cultural Assimilation into Winning
Group: The cultural models for the losing group are all drawn from the
winning group. (See 4. Updating)
pa(h)=ah / (ah + bh + gh)
is a measure of biased cultural transmission. The probability that a
Grabber or a Punisher is drawn for the cultural model pool is calculated
in similar fashion.
Each member migrates to one of neighboring groups. Each agent has chance to migrate to one of
neighboring groups with probability 0.2. To keep group size constant,
whenever an agent in group x migrates to group y, an agent in group y is
assumed to migrate to group x
Go to the step 2.