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."

algorithms

[cynicsreport]

There are several very interesting optimization algorithms based on swarm behavior, such as particle swarm optimization [wikipedia.org] and ant colony optimization [ulb.ac.be]. These methods have a similar ability for non-linear optimization (and pattern recognition) as neural networks.

Swarm simulations?

[FlyingSquidStudios]

I would like to welcome Slashdot to 1986 [wikipedia.org].

Re:it's funny because it's true

[Anonymous Coward]

Actually, studies have been done and Democratic voters are generally less educated and less informed. See the book --> "If Democrats Had Brains, They'd Be Republicans" by Ann Coulter. Or just watch the people lined up to vote in any majority Democrat district. It's like watching the inmates milling around at the asylum. Some things are true whether you believe them or not.

Re:Boids

[m0nstr42]

I didn't RTFA, but I wonder if the guy's work is related to an old artificial life simulation called Boids. The developer of Boids was able to model the flocking behavior of birds by formulating some relatively simple rules. When I first learned about the program, it sounded really neat, and according to Wikipedia it's still used in computer graphics to model flocking behavior.

The rules are quite similar, but the treatment is different. Boids was an artificial life simulation experiment. The stuff TFA refers to is intended as a simplified model of a set of mechanistic rules to describe animal behavior. The parameter space is explored with the goal of discovering behaviors that may be argued to have analogs in actual animal groups.

Re:Locusts and cannibalism

[m0nstr42]

My favorite thing about Dr. Couzin is his willingness to work with people in other disciplines - particularly the "harder" sciences. It's mentioned towards the end of the article. My advisor, Naomi Leonard, and her students have published several papers with Iain as a co-author - see http://www.princeton.edu/~naomi/ [princeton.edu] and search for "Couzin" and "Levin" on the page for a few references. Dr. Grunbaum, who is also mentioned in the article, is great with this as well (also on the page). They are both fantastic guys to work with.

And a shameless plug for my tiny contribution - http://www.princeton.edu/~dswain/publications/2007/DSCDC07.pdf [princeton.edu]

these are models... what about experiments?

[dummkopf]

Currently, Physics Today [aip.org] has an article about the swarming of birds. The studies from the group in Rome [roma1.infn.it] are expected to complement current models since currently there is little experimental evidence to back up the models. Using several cameras they take time-lapse pictures of the swarms and then reconstruct the complex trajectories on the computer (a tour de force...).

Background paper

[sTeF]

I recently read one of his papers: Collective Memory and Spatial Sorting in Animal Groups [princeton.edu]. It is a great read, the most interesting results? states of individuals have an effect on the swarm, you don't have to be aware even of the swarm, simple parameters such as perimeters, closeness to other swarm individuals can have a dramatic effect.

the other interesting result is, that the next state of the swarm can depend on states in the past, this leads to spatial memory effect.

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

[m0nstr42]

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.

Check out http://www.princeton.edu/~naomi [princeton.edu] You will find several papers co-authored by Iain.

We apply tools like nonlinear control theory and graph theory to study these kinds of "rules" with rigor, with the aim of a) designing robotic (specifically mobile sensor) networks that are bio-inspired in the way you mentioned and b) help the biologists by providing insight from our perspective.

Re:Just like fractals

[Explodicle]

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

See also: Gaia hypothesis [wikipedia.org].