Saturday, November 14, 2009

Self Organizing Flocks

This amazing video of a large flock of starlings making elaborate and intricate patterns in the sky above Denmark has been making the rounds on blogs and news sites lately:

Many of the bloggers pose the question: why do the birds do this? The answer actually lies in the physics of self-organizing systems.

Bird flocking is a well-known example of the self-organization phenomenon. No one bird is in charge, yet the flock as a whole organizes itself into beautiful patterns. Each bird takes note of its neighbor's position and direction of motion and adjusts accordingly, but nobody is the leader. No "head bird" tells the entire flock which way to go, yet they move as a unit.

Other videos of this phenomenon exist and it is sometimes the case that a predator is present. A hawk or other bird of prey could be present here as well, although it would be difficult to see it in such a large crowd of birds.

The predator's presence can explain what is causing the birds to fly around, rather than to sit quietly on the ground or in trees, but it cannot explain the intricate patterns that the starlings exhibit in their attempt to escape the predator. The theory of self-organizing systems is needed to understand the origin of these gorgeous patterns.

I have written about this phenomenon in earlier posts, since it applies to human behavior, too. Traffic and the movements of large crowds of pedestrians can be understood using this approach. It is not just birds who flock - people do, too!


  1. Wonderful! I've also put this on my Facebook and re-tweeted it. Have you ever watched Whooping cranes circle as they fly?

  2. we share similar interests!

    so if i take the risk and say
    collaboration is emergent
    does this ring true with you?

    be well!

  3. I would rather say that collaboration is a mechanism by which emergent phenomena arise. Nobody imposes collaboration from the outside - it arises naturally from relationships between the individuals - so it sounds like it would fit the definition of "emergent." But it isn't the same as flocking, like we see here with the birds, which is a pattern of behavior that arises from their "collaboration," if you will. Does that make sense to you?

  4. That is really cool. I was doing a little poking around online to see if there is an application to this kind of algorithm. Some early Artificial Intelligence models are suggesting that conciousness could be an emergent property of our intricate neuronal connections. It'll be really cool in a couple of decades when our computer chip-sets get complex enough to answer these questions. Where is our mind? Can we simulate a soul? All of these things could be answered in our lifetime. Disappointing and exciting at the same time. No?

  5. Yes, people have long suggested that consciousness could be considered to be an emergent property of the complex system we call the brain. Does this extend to what you call "soul"? Maybe - there are researchers at MIT developing robots who interact with humans in ways that make them appear (to us) to be sentient. Does this mean these robots have a soul? I think that's a question I will avoid answering... :)

  6. Wow! Now every time I see a flock of birds I'll be watching for a hawk. Check out bird removal NJ if they choose to flock to your house.