Pedro Andrade Gilberto Câmara Sugarscape Pedro Andrade Gilberto Câmara

The Sugarscape Model Building artificial societies that model certain characteristics of real ones

The Sugarscape Model: Rules Agents movement rule sex rule cultural transmission rule Cells sugar growth rule

Cells produce sugar: rule Gα Each cell grows α units of sugar by time step up to capacity

Sugarscape: Agents consume sugar Agents look for sugar to eat Agents attributes (age, wealth)

Sugarscape: Simple agent Look for a random neighbor Moves there if it has more sugar than the current cell to eat.

More complex Agent Look for a random neighbor and moves whenever it has more sugar than the current cell. Initial wealth (sugar) between 5 and 25 Metabolism between 1 and 4 sugar per each step Age starting with zero and increasing by one per time step Die by age (maximum age between 60 and 100) Die by absence of wealth Whenever it dies, creates another agent and put it in a random cell

Sugar and Agents Cells = Sugar Level, Capacity, Growback rule (Gα) Fixed: Metabolism, Vision Variable: Location, Sugar holdings Movement rule (M)

Agent metabolism Agents burn a fixed (but different) β amount of sugar per unit time ( 1 ≤ β ≤ 4 )

Agent vision Agents see in four directions with a random γ field of view ( 1 ≤ γ ≤ 4 )

Agents carry food with them Agents have an initial quantity of food They also carry food that has not been eaten

Agent movement rule Look out as far as vision enables – find the closest empty place with the most sugar Move there and get all the sugar

Agent survival Agents collect sugar and consume When they have no sugar, they die

Sugarscape society Under {G∞ ,M} Immediate growback Natural Selection Agents stick to the ridges of the sugarscape Under {G1 ,M} Constant growback (one unit per time) Natural Selection is more pronounced Two agent colonies – one in each mountain

Wealth Distribution Add a rule: Replacement (R[a,b]) Lorenz Curve and Gini Coefficient Pareto’s law in action Wealth under {G1 ,M, R[60,100]} Symmetric  Poverty-skewed

Social Networks Neighbor connection network Netlogo model? von Neumann (4) / Moore (8) neighborhoods Netlogo model?

Migration Migration under {G1 ,M} Seasonal migration under {Sαβγ,M} Netlogo model Emergence – diagonal waves! Seasonal migration under {Sαβγ,M} Hibernators and Migrators Pollution under {G1 , Pαβ, Dα,M} Pollution only – forced off mountains, starvation Diffusion – living on the edges, making things worse

Changes How to improve the movement to find more sugar? What happens with the average wealth and average age when the number of agents grow?