Emergent Behavior

Have you ever seen natural phenomena like fish schooling or bird flocking? Have you ever thought of how birds or fish produce these phenomena?

They are really eye-catching because they present a beautiful collective behaviour. However, if you fix your attention, you can’t find a leader who directs these movements. So, how are they able to produce it? The answer is relatively simple: it is a collective behavior. Each bird has a rather simple movement, but the interaction with the neighbors (local interaction) produces that each one of them follows some plain rules. So, the important thing is not the movement of each bird, it is the interaction among them. These interactions produce an emergent behavior.

In 1986 Craig Reynolds developed a simulation which recreates the flocking behavior in birds. This program only needs three rules:

1.    Each bird can’t go far away from the others.

2.    Each bird tends to line up with its neighbors.

3.    Each bird gravitates towards the center of mass of the group.

Following these simple rules it is possible to recreate the birds behavior. In the following video, you can see how they start from a random position and after a while they move in a similar way to a real flock.

Don’t you think it’s wonderful to understand this natural behaviour? Complex systems allow us to do so!

Now, if you want to have fun, go to Experiments and Games.