This weekend, I made another model. This one is built on a model explored by Carl Lipo and Terry Hunt in their book The Statues that Walked exploring the evolutionary value of cooperation and competition. At least, it’s built on the concept, since I haven’t read the book and I haven’t seen their original model. But the concept is simple. You have hawks and doves – hawks always want to fight, and doves always want to cooperate and avoid confrontation. Doves share points by cooperating, hawks take points by intimidating doves and by fighting other hawks. However, hawks also loose points if they loose a fight with another hawk. In one scenario I read – and used as an activity in my class – the “reward” is 10 points, which is either split by cooperating doves or claimed entirely by intimidating or winning hawks. The penalty for hawks losing a fight is 30 points.
After running this scenario in class, I wanted to explore other possibilities, so I decided to write my own model where you could vary the costs and benefits of cooperation and engaging in combat, and where doves could also lose points when they are intimidated. I also built in a system where you could have hawks chase doves and/or one another, and you could have doves run from hawks and/or towards one another. Here’s the interface:
The results of playing with these variables are some interesting patterns of interaction – mostly it’s fun to watch the flocking and dispersal behavior of the different agents depending on how you configure their behavior (watch a video here: Hawks-Doves). You can download the model here if you’re interested in running it yourself.
Obviously, there are still major assumptions built into the model (e.g. that agents can be split into discrete groups of hawks and doves, that they don’t change, etc.), and there are still serious limitations to the model, but it’s an interesting exercise, and fascinating to see the different patterns or behavior and outcomes depending on the variables. Please let me know if you see any way I can improve this model.
Update 11/24/2015 11:31AM: I modified some of the interface on the model and included a setting that will allow you to run the scenario repeatedly. The new model can be downloaded here.