The Rules of the Swarm

Hugh Pickens writes "Researchers are starting to discover the simple rules that allow swarms of thousands of relatively simple animals to form a collective brain able to make decisions and move like a single organism. To get a sense of swarms, Dr. Iain Couzin, a mathematical biologist at the Collective Animal Behaviour Laboratory at Princeton University, builds computer models of virtual swarms with thousands of individual agents that he can program to follow a few simple rules. Among the findings are that swarm behavior has patterns common to many different species, that just as liquid water can suddenly begin to boil, swarm behavior can also change abruptly in character, and that just a few leaders can guide a swarm effectively by creating a bias in the swarm's movement that steers it in a particular direction. The rules of the swarm may also apply to the cells inside our bodies and researchers are working with cancer biologists to discover the rules by which cancer cells work together to build tumors or migrate through tissues. Even brain cells may follow the same rules for collective behavior seen in locusts or fish. "How does your brain take this information and come to a collective decision about what you're seeing?" Dr. Couzin says. The answer, he suspects, may lie in our inner swarm."

Just like fractals

[Gabest]

We are already "cells" of a thing called "economy", for an alien the earth may just look like a single living being.

I think the acient chinese may have been onto it..

[Anonymous Coward]

sounds an awful lot like our "chi"

Re:it's funny because it's true

[Anonymous Coward]

Yes, because of course the average (and I mean **average**) Democrats is any more informed and makes their decision based on their indepth knowledge of the issues and having weighed all options...

Jeebus. Just shut up. The fact is that MOST people vote for whomever is offering them what they want, be it welfare or bombing some turd-world country. The few rational, enlightened individuals who are NOT bent on exploiting the mob tendencies of the voting bloc for either party (if you think Democratic or Republican candidates say what they say because they believe it and not just because they know that certain segments of the population will come to heal and show up on election day, then please tell me - what does it feel like to be part of a hoard?) support neither the Republicans nor the Democrats. However, there are few of those people despite the large numbers who speak against both. Most of them are just apathetic losers who can't be bothered, and that's a good thing for they shouldn't be voting anyway.

Stand Alone Complex?

[necro2607]

"... just a few leaders can guide a swarm effectively by creating a bias in the swarm's movement that steers it in a particular direction"

Wow, did this remind anyone else somewhat of Ghost In The Shell: Stand Alone Complex [wikipedia.org] and the Laughing Man and Individual Eleven cases? Plus there is plenty of discussion throughout the series about how subtle influence by a select few can affect the whole of society, unnoticed. I know it's a bit different, but it's kind of unreal to be hearing about this in the news after having only just recently watched the two seasons of Stand Alone Complex episodes...

Locusts and cannibalism

[FleaPlus]

Cool to see Couzin on slashdot... I coincidentally saw a talk of his last week and gave him a brief lab tour. His own research is somewhat outside my area, but one of the most surprising things I recall from his talk is that marching locust swarms are apparently propelled by cannibalistic behavior. If I'm remembering correctly, baby locusts (before they've grown wings) in a region will feed in a pretty disorderly fashion. However, once salt and protein supplies start running low, they get hungry and start trying to eat each other. The researchers realized this when the locusts in their enclosure seemed to be mysteriously disappearing at a steady rate, due to being consumed by their peers. ;)

In any case, once they start eating each other, the locusts start trying to chase the locusts in front of them, while simultaneously avoiding the locusts behind them trying to eat them. The emergent behavior is that the entire swarm moves as a mass until a new area is found where salt and protein supplies are plentiful enough to cause them to switch out of cannibalism-mode. This presumably has a number of ramification on how to control migration of locust swarms, which are an immense destroyer of food resources in the developing world.

Re:The Rules of the Swarm... on slashdot.

[catmistake]

~160 years ago, Søren Kierkegaard worked out the First Philosophy of the human swarm:
The crowd is untruth.

Re:The Rules of the Swarm... on slashdot.

[m0nstr42]

The article is a popular science article, but addresses this, more interesting, question much more than the summary. They discuss some of the rules involved in specific situations (ants), and even look at "human swarms" (although that bit is a little cheesy). There is no general theory posited about how to make these rule sets though, apart from trial and error (in simulation if you can). They say that the researchers are starting to see patterns, but don't talk about what those patterns are - pity really, as that would have been very interesting.

Check out Dr. Couzin's web site: http://www.princeton.edu/~icouzin [princeton.edu] there are lots of great papers there.

One common set of rules is (related to boids) 1. Move away from those closest to you. 2. Move towards those farthest from you. 3. Align with those in the middle.

On the other hand, it would be erroneous to posit a common set of rules for every species. Different evolutionary pressures produce different behaviors in different situations. An interesting facet of this type of research is to see how different sets of parameters for the same set of rules can produce different behaviors, or different sequences of behaviors.

Re:The Rules of the Swarm... on slashdot.

[skiingyac]

I can't speak for him directly, but I've been to one of his talks and read a bunch of his papers. Basically, the 3 rules for bird/fish/etc movement are very simple and are surprisingly robust. But, it is extremely difficult to reverse-engineer the rules. Sure, those 3 rules are simple enough, but are they the ones actually used by the animals? You can't exactly ask them. And then there are questions about whether an individual gives more weight to a neighboring individual which it can only hear and not see (because it is behind them), or to what extent an individual's own sense of direction and instincts plays a part. Animals have tons of senses, each with tons of dimensions.

Then there are behaviors like in geese where if one goose in a migrating flock is injured/sick/tired/dying, another goose will leave the flock (the rest of which continues on) and this other goose waits until the first goose is better (or dies) and then they continue the migration. What is the rule for that? It is just as hard to fine-tune a given set of rules except via experiment/simulation since there's not much mathematical theory behind this yet (though I believe he's got some started).

Then there are things like, we'd like to make robot swarms and we want them to act like birds except do X instead of Y. Even if the natural behaviors are modeled it is very difficult to figure out what rules to add/change/delete to get the desired change. Or, we want the robots to do natural thing X, but we need some guarantee that they will do it with some level of accuracy and we need a kill switch in case they become self-aware. This field is wide open and is extremely interesting, because even if we're not explicitly mimicking natural phenomenon we are anyway when we have groups of things (computerized or otherwise) that have many individual components with complex and somewhat autonomous interactions.

Re:it's funny because it's true

[innerweb]

For our next trick, we will quote Rush Limbaugh and Howard Stern as principles of honesty and integrity in reporting.

Group think is really a misnomer. Group think is really a large bunch of individuals not thinking (or thinking at a minimal level). So, republicans, democrats, libertarians, religious assemblies, whatever, is just minimal thinking individuals participating in groups guided by a few individuals in swarm behavior. It really does make so much sense this way. It has almost always worked when marketing. That is why marketers want a buzz about their ads and products, it promotes a swarm (mob) mentality about the product in question.

It is funny, but I think this will have more impact on marketing in the next 10 years than anything else.

InnerWeb

Re:it's funny because it's true

[The Raven]

Overtones of Psychohistory [wikipedia.org]. Luckily, later research into chaos and information theory has pretty much ruled out the possibility of Psychohistory being real.