Swarms teach us that leaders should create conditions for collective decisions, learns John Whitfield.
- Thomas D. Seeley
You can never tell when apparently blue-sky science will be useful, as biologist Thomas Seeley's career shows. His knowledge of honeybees, for example, helped to defuse a cold-war confrontation in the 1980s, when he showed that yellow dots on Thai jungle foliage were not residues of Soviet chemical weapons but bee shit. And he has run his own department by the rules that swarms use to select a new home. Honeybee Democracy describes Seeley's quest to understand collective decision-making in social insects and humans.
Bee swarming is impressive and mysterious. Early in summer, a queen honeybee flies from her hive with a retinue of about 10,000 workers, leaving the home of her birth to be inherited by a daughter. The swarm might bivouac on a handy surface for several days before invading a new nest site in a tree hollow or building cavity. The collective must quickly decide where to settle, because it is risky to hang around in the open as food reserves dwindle. And it is important to pick the right spot — a colony that chooses poorly is unlikely to survive the winter.
Bees communicate through dancing. In the 1940s, German biologist Karl von Frisch decoded the waggle that worker bees perform to recruit foragers to food sources — the dance shows the direction, distance and quality of the food. His student, Martin Lindauer, noticed that during swarming some dancing honeybees were not covered in pollen, as were returning foragers, but in brick dust. He suspected that they had returned from potential nest sites, and were advertising them to their swarm-mates. By reading that dance, he worked out the site's probable location, and confirmed his hunch by following the swarm through the streets of Munich to its new home.
Seeley picked up the baton in the 1970s. Honeybee Democracy describes how, in a series of ingenious experiments, he deduced what kind of site bees prefer — a cavity of about 40 litres with a small entrance that faces south — and how a swarm homes in on the best of many possible nest sites. His story's heroines are the scout bees, a few hundred workers who trigger the swarm's departure, seek out nest sites, debate their merits, come to a decision, rouse the swarm and guide it to the new home.
A scout converts knowledge of a particular nest site into a waggle dance. The better the site, the longer and harder she dances. If another scout bumps into a dancing bee, she goes off to inspect the site. If she likes it, she too will dance. But any bee only advertises a site for a few hours, even if she has found a dream home.
This stops the swarm jumping to a premature conclusion — a vital delay, as the best site is rarely found first. Eventually, the dynamics of dancing cause about 20–30 scouts to arrive at a single, high-quality nest site. Once this quorum is reached, the scouts stop the debate and communicate their decision to the swarm with high-pitched piping sounds and by running amid the other bees buzzing their wings, a preflight routine. The swarm then warms up and moves off, the scouts pointing the way.
This form of decision-making is extremely robust. Each bee's job is simple. Even if one makes a mistake, the rules that transform individual deeds into collective behaviour set the swarm back on course. Other systems have independently evolved the same tricks. A neuron, for example, carries little information. But by using similar rules to bees, cells combine to enable our brains to do clever things, such as tracking a moving object.
In the final chapter, Seeley lists his bee-derived rules for good human decision-making, and describes how he applied them as head of Cornell University's neurobiology and behaviour department in Ithaca, New York. He points out that groups make the best decisions when leaders interfere as little as possible. Individuals are then free to explore and debate options, and are most likely to arrive at the best decision. The wise leader, he advises, manages the process of decision-making and lets the product take care of itself.
In his own community, Seeley ensured that all possibilities were considered and that everyone had his or her say. He then stepped back to let the group make up its own mind by secret ballot. Such a process (discovered by several human societies independently) ought to work well in situations where a group with a common interest chooses between many options, from friends choosing a holiday destination to a government poised to invest billions in a defence system.
However, this rule about leaders facilitating decisions rather than making them is also the one humans find hardest to apply. Why struggle to the top if you can't push your own agenda? Or why pick leaders if they don't make their presence felt? In a crowd-sourcing exercise this year by the new UK government, for example, the public was asked to propose policy ideas and money-saving tips. Thousands of suggestions came in. But people were not asked to choose between the proposals. The decisions remained with those at the top. Humans prize their power and expertise — and that, Seeley's splendid book suggests, may be a cause of many of our problems.