Computational Model Library

Variations on the Ethnocentrism Model of Hammond and Axelrod

In the original model of Hammond and Axelrod (2006), agents populate a lattice and interact with their immediate neighbours in a prisoner’s dilemma. Agents have a tag, and one strategy towards agents with the same tag and one towards those with a different tag. Depending on success in previous interactions, agents reproduce onto neighbouring patches.

The model has been scrutinised with several adjustments in the paper “Pitfalls in Spatial Modelling of Ethnocentrism” and this Java package contains the implementation of the different models used there, allowing for the following modifications to the original model:

Spatial structure:

Lattice with wrap-around borders

with up to 24 neighbours

Small-world network
Well-mixed population (no spatial structure)

with different weights for in- and outgroup interactions


Agents discriminating on tag

with tags and strategies mutating at different rates
with tags being difficult to perceive

Agents recognising and discriminating on kin relations

Release Notes

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Version Submitter First published Last modified
1.0.0 Fredrik Jansson Nov 10, 2012 Apr 27, 2013