What you just saw
Agents start with identical rules but varied vision and metabolism. After a few hundred steps, a small fraction of the population controls most of the wealth. The Gini coefficient climbs past 0.7 — inequality we normally associate with real economies — purely from heterogeneity and local harvest rules, with no policy, no coercion, no central planner.
The science behind it
Joshua Epstein and Robert Axtell introduced Sugarscape in their 1996 book Growing Artificial Societies. It is the canonical demonstration that significant economic inequality can emerge from simple individual-level rules. Extensions include inheritance, trade, combat, and cultural transmission — each one producing qualitatively different societies. It is a foundational model for computational economics.
Try these experiments
1. Slow regrowth
Settings: regrowth_rate=0.3
What to look for: High inequality, small population. The landscape can't support many agents.
2. Abundance
Settings: regrowth_rate=3
What to look for: Lower Gini, larger stable population. Abundance reduces inequality.
3. Crowded start
Settings: initial_population=800
What to look for: Rapid die-off as agents exhaust the sugar faster than it regrows. Sharp population crash.
Run this at 100x scale
Sugarscape runs in your browser up to 400 agents. With SimLab, the same model runs on GPU at 1M+, with ensemble parameter sweeps and publication-ready output.
from scirouter import SciRouter
client = SciRouter(api_key="sk-sci-...")
result = client.simulation.run(
model="sugarscape",
params={"grid_size": 200, "initial_population": 50_000,
"regrowth_rate": 1.0},
steps=1000, seed=42,
)
print(result.metrics["gini_coefficient"])Related simulations
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Frequently asked questions
What is the Gini coefficient?›
A number between 0 (perfect equality) and 1 (one person owns everything). Real-world national Gini values range from ~0.25 (Nordic countries) to ~0.65 (highly unequal economies). Sugarscape routinely produces Gini around 0.5–0.8.
Why does inequality emerge?›
Small random differences at start — vision, metabolism, starting sugar — compound over time. Agents with slightly better vision find sugar first, grow faster, and outcompete weaker neighbors. The system has positive feedback for the wealthy.