Axelrod Model
This section begins with Robert Axelrod's puzzle: how can cultural diversity emerge from local processes of imitation? Axelrod answers the question with the following paper, in which he presents an agent-based model of cultural diffusion.
Axelrod - Cultural Diffusion
This is a NetLogo implementation of Axelrod's Model.
Axelrod Model
Cultural Drift and Networks
At the end of his paper, Axelrod poses a question about the effects of 'cultural drift' on the dynamics of his model. This quesion was taken up by a group of physicists in Spain, who in a series of papers explored the effects of network topology
Network Topology and Cultural Diffusion
and noise
Cultural Drift and Cultural Diffusion
on the dynamics of Axelrod's cultural diffusion model.
These papers showed that under even very small levels of noise (or cultural drift), Axelrod's model of cultural diffusion could not support diversity - indeed, noise drives the system into a state of global monoculture.
Extending Axelrod
These results raised the question of how Axelrod's original puzzle could be solved even in the presence of noise
Michael Macy and colleagues addressed this problem by extending a Hopfield neural network model to include positive and negative attraction.
Polarization Dynamics in Hopfield Model
Damon Centola and colleagues addressed the problem by developing a dynamic network model, which evolves stable multi-cultural configurations even without negativity.
We also presented this puzzle to the students in the course, giving them an opportunity to experiment with the Axelrod model, and to extend it in ways that they thought would be interesting.
This extension by Steven Bernard explores the effects of a non-linear (sigmoidal) decision algorithm on the dynamics of the model.
SigmoidalAxelrod
This extension by Michael Wonder adds negativity to the model.
NegativityAxelrod
