One of the many fine things about the internet – and in particular that great internet business, Amazon – is that you can now easily get hold of books that seem interesting, even if they were published a decade and a half ago.  Steven Johnson’s book, Emergence, for instance.  This was published in 2001.  I think it was some Amazon robot system that reckoned I might like it ("lots of people who bought this book you just bought also bought this one").  And I read some Amazon reviews, or whatever, and I did like it, or at least the sound of it, and I duly sent off for it.  (I paid £0.01 plus postage.) And now I’m reading it.

Chapter one of Emergence is entitled “The Myth of the Ant Queen”.  Here is the part of that chapter that describes the research then being done by Deborah Gordon, into ants:

At the heart of Gordon’s work is a mystery about how ant colonies develop, a mystery that has implications extending far beyond the parched earth of the Arizona desert to our cities, our brains, our immune systems - and increasingly, our technology.  Gordon’s work focuses on the connection between the microbehavior of individual ants and the overall behavior of the colonies themselves, and part of that research involves tracking the life cycles of individual colonies, following them year after year as they scour the desert floor for food, competing with other colonies for territory, and - once a year - mating with them.  She is a student, in other words, of a particular kind of emergent, self-organizing system.

Dig up a colony of native harvester ants and you’ll almost invariably find that the queen is missing.  To track down the colony’s matriarch, you need to examine the bottom of the hole you’ve just dug to excavate the colony: you’ll find a narrow, almost invisible passageway that leads another two feet underground, to a tiny vestibule burrowed out of the earth. There you will find the queen.  She will have been secreted there by a handful of ladies-in-waiting at the first sign of disturbance.  That passageway, in other words, is an emergency escape hatch, not unlike a fallout shelter buried deep below the West Wing.

But despite the Secret Service-like behavior, and the regal nomenclature, there’s nothing hierarchical about the way an ant colony does its thinking. ‘’Although queen is a term that reminds us of human political systems,” Gordon explains, “the queen is not an authority figure. She lays eggs and is fed and cared for by the workers.  She does not decide which worker does what.  In a harvester ant colony, many feet of intricate tunnels and chambers and thousands of ants separate the queen, surrounded by interior workers, from the ants working outside the nest and using only the chambers near the surface.  It would be physically impossible for the queen to direct every worker’s decision about which task to perform and when.” The harvester ants that carry the queen off to her escape hatch do so not because they’ve been ordered to by their leader; they do it because the queen ant is responsible for giving birth to all the members of the colony, and so it’s in the colony’s best interest - and the colony’s gene pool-to keep the queen safe. Their genes instruct them to protect their mother, the same way their genes instruct them to forage for food. In other words, the matriarch doesn’t train her servants to protect her, evolution does.

Popular culture trades in Stalinist ant stereotypes - witness the authoritarian colony regime in the animated film Antz - but in fact, colonies are the exact opposite of command economies.  While they are capable of remarkably coordinated feats of task allocation, there are no Five-Year Plans in the ant kingdom.  The colonies that Gordon studies display some of nature’s most mesmerizing decentralized behavior: intelligence and personality and learning that emerges from the bottom up.

I’m still gazing into the latticework of plastic tubing when Gordon directs my attention to the two expansive white boards attached to the main colony space, one stacked on top of the other and connected by a ramp.  (Imagine a two-story parking garage built next to a subway stop.) A handful of ants meander across each plank, some porting crumblike objects on their back, others apparently just out for a stroll. If this is the Central Park of Cordon’s ant metropolis, I think, it must be a workday.

Gordon gestures to the near corner of the top board, four inches from the ramp to the lower level, where a pile of strangely textured dust - littered with tiny shells and husks-presses neatly against the wall.  “That’s the midden,” she says. “It’s the town garbage dump.” She points to three ants marching up the ramp, each barely visible beneath a comically oversize shell. “These ants are on midden duty: they take the trash that’s left over from the food they’ve collected-in this case, the seeds from stalk grass-and deposit it in the midden pile.”

Gordon takes two quick steps down to the other side of the table, at the far end away from the ramp. She points to what looks like another pile of dust. “And this is the cemetery.” I look again, startled.  She’s right: hundreds of ant carcasses are piled atop one another, all carefully wedged against the table’s corner.  It looks brutal, and yet also strangely methodical.

I know enough about colony behavior to nod in amazement. “So they’ve somehow collectively decided to utilize these two areas as trash heap and cemetery,” I say. No individual ant defined those areas, no central planner zoned one area for trash, the other for the dead. “It just sort of happened, right?”

Cordon smiles, and it’s clear that I’ve missed something. “It’s better than that,” she says. “Look at what actually happened here: they’ve built the cemetery at exactly the point that’s furthest away from the colony. And the midden is even more interesting: they’ve put it at precisely the point that maximizes its distance from both the colony and the cemetery. It’s like there’s a rule they’re following: put the dead ants as far away as possible, and put the midden as far away as possible without putting it near the dead ants.” I have to take a few seconds to do the geometry myself, and sure enough, the ants have got it right. I find myself laughing out loud at the thought: it’s as though they’ve solved one of those spatial math tests that appear on standardized tests, conjuring up a solution that’s perfectly tailored to their environment, a solution that might easily stump an eight-year-old human.  The question is, who’s doing the conjuring?

It’s a question with a long and august history, one that is scarcely limited to the collective behavior of ant colonies.  We know the answer now because we have developed powerful tools for thinking about - and modeling - the emergent intelligence of self-organizing systems, but that answer was not always so clear.  We know now that systems like ant colonies don’t have real leaders, that the very idea of an ant “queen” is misleading. But the desire to find pacemakers in such systems has always been powerful-in both the group behavior of the social insects, and in the collective human behavior that creates a living city.