The Nobel Prize for understanding the hypnotic flight of a flock of birds

A flock of starlings fly in a group over a field near Kiryat Gat, southern Israel, on January 3, 2020. REUTERS / Amir Cohen

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Good Morning! Today I want to talk to you about complex systems (but with videos of birds).

What connects changes in the weather with the hypnotic movement of a flock of starlings? This week three physicists have won the Nobel for helping us understand complex systems, the family of phenomena where these two things come in, from atmospheres to little birds.

These systems are defined by their interactions. We say that they are complex because they have a large number of components that together produce non-trivial behaviors that cannot be explained by looking at their pieces separately. They transcend the sum of their parts, as happens with the human body, with viral fashions, with car traffic, with certain markets and, of course, with the Earth’s climate.

They are phenomena subject to the paradox of simplicity. Can anything complicated come out of very simple agents? Of course it can. The proof is the thought that is now in your head, whatever you are thinking, that emerges (we don’t know how) from the connection of thousands of neurons that one by one, separately, do little thing.

The Italian Giorgio Parisi, one of the winners, has dedicated his life to understanding that, how simple behaviors can rise and lead to complex behaviors. It is not easy at all. Climate does not behave in a certain way because it has parts that make A or make B, but it evolves and is disturbed by the collision of a million connected phenomena. It is difficult to predict such phenomena. You have to anticipate the outcome of all these interactions, like someone trying to guess where the balls will go when opening a pool game. That is why climate change has been studied with simulations and mathematical models, such as those that now win the Nobel. Because these models serve to predict the future, indeed, but also for a preliminary step: confirming that we understand how the world works. (What you don’t know how to imitate, you really don’t understand.)

But today I don’t want to talk about the weather, but about the birds.

Parisi has worked with many complex systems, but the most colorful of all are flocks of birds. Behold this amazing video of a group of flailing starlings attacked by a hawk.

A hawk (barely seen) trying to hunt a group of starlings.
A hawk (barely seen) trying to hunt a group of starlings.

There are hundreds of birds that move in waves, in a mixture of order (they flow) and chaos (it is difficult to predict where they will go). But how do they know how to do something like that? The flock is an example of complexity. Individual birds cannot fly in waves. Humans, although we are smarter, neither: imagine that you put 100 of us on a soccer field, and asked us to make waves like that, we would be incapable … because it is too complicated. The incredible thing is that this complexity arises naturally from something embedded in the birds.

His movements are a emergent property. It has been shown with simulations that to create these patterns just have birds that follow simple rules: Align yourself with your neighbors, avoid areas where you are too many, do not move away from the group. The birds in the flock are believed to only really interact with about seven close neighbors, but because they form a network, they all end up connecting with everyone. Literally. It is said by one of Parisi’s works: “The behavior change of an animal affects and is affected by all the animals in the group, no matter how big it is.” This is what they call scale-free correlations.

A flock of birds, seen in the Reddit group 'Murmuration', where there are dozens of fantastic shots.
A flock of birds, seen in the Reddit group ‘Murmuration’, where there are dozens of fantastic shots.

This connection means that the information will flow through the whole, which becomes hyper-reactive, as Parisi and his colleagues explain: “Flocks are a critical system, perfectly tuned to respond in a maximum way to disturbances in the environment.” The result, like count this other article, is incredible agility: “A turn signal, usually started by a suburban bird, can run through a flock of 400 birds in half a second.”

How the birds do this, we do not know. Why do they, either. When a hawk appears, the starlings may form flocks and move in unison to protect themselves. But why do they do it without predators nearby? The professor of evolutionary sciences, Charlotte Hemelrijk, does not rule out almost anything: “It is possible to see these exhibitions as a form of dance”.

Sheep do the same too, by the way. Behold.

Photographer Lior Patel followed a flock of sheep with a drone for months. The video is a small cut of the complete piece.
Photographer Lior Patel followed a flock of sheep with a drone for months. The video is a small cut of the complete piece.

And we humans make them too.

Many things that worry us happen without anyone deciding, such as when we continue to warm the planet a little together, although we know that it is a bad idea. Many things happen, or persist, because of what millions of people do, whether it is making rents more expensive or the inequality between good and bad schools. We do not all have the same responsibility, of course, but perhaps we have more than we like to assume. But explaining things like this goes against our nature: our impulse is to point out those responsible. If the pandemic was harsh with Spain at the beginning, or if it was with Madrid, what comes to mind is to think of the culprits rather than the complex interaction of many factors.

A paradoxical example is the Nobel Prize winners. They are a fantastic celebration of science, which does not make much sense to criticize, but does allow for criticism. Journalist Ed Yong said years ago that the awards support a distorted view of scientific work. The Nobel laureates reward one, two or three people for a scientific discovery, as if those achievements were the fruit of solitary geniuses, and even an instant of brilliance, when the reality of today’s science is very different today. The great advances are the result of the work of many people who interact, like a flock of scientists who produce wonders without anyone knowing how.

Other ‘random’ stories

💶 1. What are Pandora Papers

What is an ‘offshore’ company? What is it for? This week in EL PAÍS we have published the result of a global investigation conducted by the International Consortium of Investigative Journalists (ICIJ) that analyzes the secret files of 14 law firms and that has brought to light opaque societies of politicians, millionaires and artists from more than 90 countries. If you want to immerse yourself in the roles, and you have not done so yet, a good place to start is this summary of my two colleagues on the subject, Daniele Grasso and Montse Hidalgo.

🏡 2. People don’t want to go to the office so much

A survey of 800 professionals, the majority of the programming industry, shows that something is changing: 80% of those surveyed say they would think about changing companies to work remotely. 80% consider it ideal not to go to the office more than 2-3 days a week, because they save time and money, and because they earn on rest and in conciliation. They also say that they are more concentrated. The study has been published by the people of Manfred, a company dedicated to recruiting.

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We would love to give thanks to the writer of this article for this outstanding material

The Nobel Prize for understanding the hypnotic flight of a flock of birds

Hank Gilbert