the most difficult kinds of problems for millions of years: Will there be enough food for the colony this week? Where will it be found? How many workers will the hive need to build a nest? How will the weather affect the herd’s migration this year? The way they’ve responded to these challenges has been to evolve a special form of group behavior that is flexible, adaptive, and reliable.
Translated into mathematical formulas, the principles of a smart swarm have given businesses powerful tools to untangle some of the knottiest problems they face. Manufacturing companies have experimented with them to optimize production, for example. Telephone companies have tested them to speed up calls. Aircraft mechanics and engineers have applied them to identify problems in new airplanes. And intelligence agents have used them to keep track of a dangerous world.
How does a smart swarm work? We’ll find out in the first three chapters by following biologists into the field to unlock the secrets of collective behavior. As these researchers have discovered, social insects such as ants, bees, and termites distribute problem solving among many individuals, each of which is following simple instructions but none of which sees the big picture. Nobody’s in charge. Nobody’s telling anybody else what to do. Instead, individuals in such groups interact with one another in countless ways until a pattern emerges—a tipping point of motion or meaning—that enables a colony of ants to find the nearest pile of seeds, or a school of herring to dodge a hungry seal.
In the fourth chapter we’ll look at the subtle role that individuals play in keeping a group on course. For groups such as flocks of birds, schools of fish, or herds of caribou, which are made up of individuals largely unrelated to one another, the key to survival demands a set of skills that balances group behavior with self-interest. As humans, we share many common problems with such groups, since we’re often torn by the same impulses—to cooperate but also to profit, to do what’s right for the community but also to look out for ourselves and our families.
Not every swarm is smart, of course. Group behavior also has a dark side. In the fifth chapter we’ll find out what scientists have discovered about locusts to explain why peaceful groups of grasshoppers suddenly explode into voracious plagues. To learn how human instincts can go haywire, we’ll also follow the work of researchers who have studied fatal crowd disasters among religious pilgrims in Saudi Arabia—and what’s been done to prevent such accidents in the future. What separates a smart swarm from its stupid cousin? Why does a happy crowd suddenly turn into a rampaging mob? The reason, simply put, is that a smart swarm uses its collective power to sort through countless possible solutions while the mob unleashes its chaotic energy against itself. And that makes it so important to understand how a smart swarm works—and how to harness its power.
As everyday life grows more complicated, we increasingly find ourselves facing the same problems of uncertainty, complexity, and change, drowning in too much information, bombarded with too much instant feedback, facing too many interconnected decisions. Whether we realize it or not, we too are caught up in worlds of collective phenomena that make it more difficult than ever to guide our companies, communities, and families with confidence. These challenges are already upon us, so we need to be prepared. The best way to do that, as you’ll see in the pages ahead, is to turn to the experts—not the ones on cable TV but those in the grass, in the air, in the lakes, and in the woods.
Just off Route 533 in southwestern New Mexico, a barbed-wire fence surrounds sixty acres of what used to be a sprawling cattle ranch at the foot of the Chiricahua Mountains. Some years ago, at the request of biologist Deborah Gordon, Stanford University bought the property to keep out of the hands of developers a small research site she’d established. But the subdivisions and convenience stores never materialized. In fact, not much at all has happened on this little patch of the Sonoran Desert to disturb the current residents of the site, including several hundred colonies of red harvester ants (Pogonomyrmex barbatus). For more than two decades now, Gordon has documented the life histories of these colonies, where, day in and day out, season after season, ants go about their business with a curious mix of efficiency and utter chaos.
The workday starts early at Colony 550, an older nest of some ten thousand ants near the eastern border of the site. From dawn to midmorning, one group after another emerges from the nest to carry out various tasks. The first on the job are patrollers, who poke their heads out of the entrance hole just before sunrise. Appearing to be in no hurry, they mill around on the circular nest mound, inspecting the pebbly surface like groundskeepers at a golf course assessing the health of a green. If something has happened during the night, patrollers will be the first ants to know. Has the rain left a pile of debris on a foraging trail? Has the wind redistributed the seeds the ants collect for food? What are the neighbors up to this morning? As they wander farther and farther from the nest entrance, patrollers may bump into scouts from nearby colonies doing exactly the same thing, and, if they do, forager ants from both sides might later fight. “Last week, for some reason, we noticed quite a few foragers walking around with the heads of other ants attached to their bodies,” says Mike Greene, a biologist from the University of Colorado–Denver who was doing research at the site. “They’d clearly been having little ant wars.”
The patrollers are soon joined by a crew of nest maintenance workers, each carrying a bit of dirt, seed husk, or other trash up from below ground. In contrast to the patrollers, they seem narrowly focused on their tasks, searching for a suitable place to deposit their loads. The moment they find one, they drop what they’re carrying, turn around, and head back down into the nest.
Next come a handful of midden workers, who tidy up what the maintenance workers have left behind. Not that they do this in any sensible way. If you watch one working for a while, Greene says, you’ll probably find it puzzling. “Midden workers remind me of my fifteen-month-old daughter. They take an object from Point A and drop it at Point B. Then they pick something else up and go to Point C. It all seems very random.” A time-lapse movie of the morning’s activity, though, would show a pile of dirt and ant trash steadily growing along one edge of the nest mound. “So it turns out they’re organized, after all,” he says.
The last to appear are the foragers, who greatly outnumber the other workers. Streaming out of the entrance hole, they charge directly for the tall grass that rings the nest mound and disappear into a sea of Mormon tea, acacia, and snakeweed. Following ant highways through the underbrush, the foragers may venture as far as sixty feet from the nest in search of seeds. Because these seeds, for the most part, have ridden the winds from other parts of the desert, rather than coming from plants on the site, they tend to be scattered in unpredictable ways. So it could take a forager as long as twenty minutes to find one. As soon as it does, it picks up the seed and carries it straight back to the nest.
By nine a.m., the nest hole has taken on the appearance of a frantic subway entrance, with ants rushing in and out. In a colony like 550, which is nearly twenty years old, the nest may be six feet deep. Down below, in an elaborate network of tunnels and chambers, as Gordon describes in her book Ants at Work, other groups of ants are busily stacking seeds in storage chambers, according to size and shape; removing dead ants, grasshopper legs, and other unwanted objects from the nest; tending brood; caring for the queen; or simply standing ready in reserve.
From top to bottom, Colony 550 seems to be a model of efficiency, with each group performing its task in an orderly sequence—an impression strengthened by each ant’s habit of constantly touching its antennae with every other ant it meets, as if to make sure that everybody’s on the same page. From patrollers and maintenance workers to midden workers and foragers, every member of the colony seems to be following a master plan, like tiny cogs in a machine or the employees of a successful factory.
But that’s not what’s happening here at all.
Despite its well-managed appearance, Colony 550 does not function like any organization you are ever likely to encounter. It has no bosses, managers, or supervisors of any kind. The queen, despite her lofty title, wields no authority. Her sole function is to lay eggs, not to give commands. When patrollers venture out into the grass,