4 . The Wisdom of Pigeons (I)
Leadership, Influence and the Power of the Flock
By Stephen Bungay
In May 2001, scientist Eric Bonabeau and consultant Christopher Meyer published an article in HBR called “Swarm Intelligence – A Whole New Way to Think About Business.” It linked systems thinking and biology.
The question it addressed is how creatures of very modest intelligence like ants and termites can create nests which are marvels of engineering, find food under adverse conditions and sustain reproductive success over countless generations, making them today some of the most successful species in the competitive environment of nature.
Ants and termites do not need a leader because they possess “swarm intelligence,” and scientists can model how swarm intelligence works in terms of a few simple behavioural rules. Complexity arises out of simplicity.
Ants’ foraging behaviour can be explained by assuming they follow just two rules: lay pheromone and follow the trails of others.
Researchers have used their behaviour to create programmes for routing telephone calls and designing freight routing for airlines. Similar business applications can be derived from how bees allocate labour. They have proved to be superior to more complex systems designed by engineers.
In the same year, Don Sull and Kathy Eisenhardt also published an HBR article about simple rules. They continued to work on the subject over the following years and in 2015 published a book called “Simple Rules” which builds on that article, modifies a few of its ideas, but above all extends its scope, covering a huge number of examples from just about every aspect of life, including online dating.
Sull and Eisenhardt cite the flocking behaviour of starlings as an example of what they call co-ordination rules: avoid collisions, head in the same direction as your nearest neighbours and stay close to your nearest neighbours.
Each individual starling can follow the rules using only local information, but the flock can respond to unpredictable local conditions, such as power lines blocking their path.
The lure of the subject is that simple rules offer a mechanism which can help us to turn strategy into action in the uncertain, complex environment most businesses face today.
They enable individuals in an organisation to act autonomously but in alignment with each other, making them effectively self-organising. Self-organising systems have evolved in nature, and evolution is pretty smart, so it is something to take seriously.
In the meantime, the scientists have also been hard at work.
In January 2016, Gabriel Popkin published an article in Nature called “The Physics of Life,” describing the experiments carried out by scientists at the molecular level.
Molecules or particles that can respond to electric fields will move randomly until they reach a certain density. At that point, they spontaneously form recognisable patterns which are similar to those created by flocks of birds.
For this phenomenon to be observed, the particles must have energy, such as magnetism or velocity derived from a molecular fuel; and there must be a certain number of them in any given space.
When they reach this critical level of density, the individual particles influence one another in such a way that they align with the velocity of their neighbours, but still show a certain amount of random variation.
The result is a pattern known as “Vicsek’s flocking model,” after Tamás Vicsek, a Hungarian biophysicist who first documented the phenomenon in a paper published in 1995.
All life forms are based on this phenomenon. The study of it is called “active-matter theory.” The phenomenon is dynamic and complex. Some people think that the processes leading to it must also be complex.
Active-matter theorists are struck by how much can be explained by just a few factors:
- Individual actors which are dynamic – there must be movement;
- Variation in the movements of the individuals;
- Critical density of the individuals in space.
At that point:
- The individuals influence one another so that they tend to coalesce towards the average with the result that a pattern emerges;
- There are still some individual variations around the average.
The biophysicists are not the only ones to have been active. So have the biologists and zoologists. So has my friend Aidan Walsh. He has been studying rule-following behaviour in organisations for some 20 years and he keeps an eye on what the scientists are up to.
He invited me to join him at the Department of Zoology in Oxford University to meet Dr. Dora Biro and her team from the Oxford Navigation Group. They study homing pigeons. They want to know how it is that homing pigeons always get home.
So it was that Aidan and I found ourselves on the M40 homing in on my alma mater, which looked at its most alluring in the bright winter sunshine. It was a great day for flying, whether you are a bird or a plane. And although we ourselves did not fly, we did have a great day.
Dora and her colleagues have about 40 pigeons housed in roosts just outside Oxford. They investigate how they navigate by attaching a small GPS device to the back of each individual, and then releasing flocks of various sizes from chosen points in the surrounding area.
The GPS devices tell them the movements of each bird, the routes followed and the time taken to return.
We discussed how pigeons navigate. Before starting on their journey home, they have to work out where they are. They do this by using smell. Even as chicks it is thought they smell chemicals carried in the air from different wind directions and learn their location that way.
This olfactory system is used when they are first released. They circle around in a flock to orientate themselves.
In actually heading for home, they use three systems.
The primary system uses the position of the sun as a compass. They take a bearing from the sun by using an internal clock. When researchers re-set this clock to the wrong time (by effectively jet-lagging the birds) they are misled by their internal clock and navigate poorly.
If heavy cloud cover, for example, prevents them from using the sun, they have a second system based on magnetism. It is less precise, but, like an aircraft’s instrumentation, works in all visibility conditions.
They also make use of a third system based on visual cues from the landscape, as would a pilot using visual flight rules. It depends on their being familiar with the territory over which they are flying, such as a river behind their home. They seem to use it mainly as a back-up.
If the ground is covered in snow, they can get confused. In general, this system seems to give them added confidence in the direction they are taking.
Each bird can therefore navigate for itself. Once they have orientated themselves, they set off, flying at up to 60 kph.
The researchers think that “each bird has its own opinion of which bearing to take.” Each has the same goal: to get home.
Apparently, homing pigeons are not better navigators than rock doves, which are the same species, but hundreds of years of selective breeding by humans has resulted in a bird that is better motivated. Some bird species are content to roost in the nearest tree. Homing pigeons really want to get home.
Note that “getting home” is a shared goal, but it is not a collective goal, one which can only be achieved by working with others. They could each get home by themselves. No bird needs the other birds to achieve that, and every bird has an opinion about the best way of doing so.
Nevertheless, they invariably form a flock and pursue their goal together. They must do that for a reason.
One benefit of flocking is safety. The main threat is from sparrowhawks. Sparrowhawks can easily pick off single birds but have a lower success rate against flocks, despite flocks’ greater visibility.
The other benefit is better navigation. It turns out that flocks have more wisdom than single birds – even the best ones.
The pigeons’ flocking behaviour can be modelled in terms of two rules:
- Stay close to your preferred route;
- Stay close to the bird next to you.
Each bird judges for itself what “close” means:
- Rule 1 means “close enough not to feel that you ought to change direction.”
- Rule 2 means “close enough to get useful cues but not so close that you collide.”
Most of the time, both rules can be satisfied, but it is not possible to follow both rules under all circumstances. At times, individual birds will have to make a decision and choose between the two rules:
- Confident birds will choose to follow rule 1 over rule 2.
- Timid birds will choose to follow rule 2 over rule 1.
Occasionally birds split off. They may do so because they are tired or sick or they are hungry and see a feeding opportunity, or because they have a radically different opinion on bearing. But in general, the flock remains together.
The researchers’ methodology allows them to study not only the flock but the movements of individuals within the flock at a very high level of precision. This is where it gets interesting.
Dora and her team wanted to know how the birds follow rule 2: stay close to the bird next to you.
They analyzed what they call the “directional correlation delay” which is the amount of time birds take to adjust their own flight direction in order to stay close to other birds. The delay is usually less than one second, but it varies, and the variations are systematic, depending on which bird others are adjusting to.
The team awarded points to each bird in the flock according to how rapidly other birds adjusted to it and discovered that a few birds’ flight patterns will be adjusted to very rapidly by other birds. In this way, such individuals have a disproportionate effect on the direction taken by the flock as a whole. In other words, within the flock there are “leaders.”
“Leader” is a loaded word. None of the birds issues orders. A “leader” in this context is a bird with fast-followers. Interestingly, this does not correspond to social hierarchy. Back at the roost there is literally a pecking order.
Dominant birds are ones which show more aggression in accessing food and so stand at the top of the flock’s social hierarchy. The “leaders” in the air are different. They are leaders in the sense that they exert greater than average influence on the flying behaviour of others, and “high-influencer” is probably a better term than “leader.”
Whilst dominant birds can be identified through their own behaviour; high-influence birds can only be identified through the behaviour of their followers.
So how do the birds choose the ones they wish to follow most rapidly?
Next month, in the second part of this article, we will explore the idea of “no absolute leaders,” the concept of “zone of latent solutions,” and how the rule-following exhibit by pigeons explains accurately most behaviour in human organisations. Stay tuned!
I am Stephen Bungay and these are my agile-thoughts
2021 © London, UNITED KINGDOM by Stephen Bungay
Stephen Bungay teaches on executive programmes at several business schools, works as an independent consultant and conference speaker, and has published several books on military history and business strategy execution.
His current work is focussed on the most effective ways of developing an agile strategy in an environment of high uncertainty.
One of his oldest passions is strategy. “As a boy I played wargames published by a US company called ‘Strategy and Tactics’. This led to an interest in military history that has been enduring. When I started looking for a job, I discovered to my surprise that there were firms called ‘strategy consultants’ that helped businesses to develop strategies. I had no idea that businesses needed them. But I was hooked, and joined the Boston Consulting Group. The rest, as they say, is history.”
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