Saturday, August 22, 2020

Complexity: "Uncertain times"

Not new thinking but interesting framing.
From Aeon Magazine:

The pandemic is an unprecedented opportunity – seeing human society as a complex system opens a better future for us all
We’re at a unique moment in the 200,000 years or so that Homo sapiens have walked the Earth. For the first time in that long history, humans are capable of coordinating on a global scale, using fine-grained data on individual behaviour, to design robust and adaptable social systems. The pandemic of 2019-20 has brought home this potential. Never before has there been a collective, empirically informed response of the magnitude that COVID-19 has demanded. Yes, the response has been ambivalent, uneven and chaotic – we are fumbling in low light, but it’s the low light of dawn.
At this historical juncture, we should acknowledge and exploit the fact we live in a complex system – a system with many interacting agents, whose collective behaviour is usually hard to predict. Understanding the key properties of complex systems can help us clarify and deal with many new and existing global challenges, from pandemics to poverty and ecological collapse.

In complex systems, the last thing that happened is almost never informative about what’s coming next. The world is always changing – partly due to factors outside our control and partly due to our own interventions. In the final pages of his novel One Hundred Years of Solitude (1967), Gabriel García Márquez highlights the paradox of how human agency at once enables and interferes with our capacity to predict the future, when he describes one of the characters translating a significant manuscript:
Before reaching the final line, however, he had already understood that he would never leave that room, for it was foreseen that the city of mirrors (or mirages) would be wiped out by the wind and exiled from the memory of men at the precise moment when Aureliano Babilonia would finish deciphering the parchments.
Our world is not so different from the vertiginous fantasies of Márquez – and the linear thinking of simple cause-effect reasoning, to which the human mind can default, is not a good policy tool. Instead, living in a complex system requires us to embrace and even harness uncertainty. Instead of attempting to narrowly forecast and control outcomes, we need to design systems that are robust and adaptable enough to weather a wide range of possible futures.

Think of hundreds of fireflies flashing together on a summer’s evening. How does that happen? A firefly’s decision to flash is thought to depend on the flashing of its neighbours. Depending on the copying rule they’re using, this coordination causes the group to synchronise in either a ‘bursty’ or ‘snappy’ fashion. In her book Patterns of Culture (1934), the anthropologist Ruth Benedict argued that each part of a social system depends on its other parts in circuitous ways. Not only are such systems nonlinear – the whole is more than the sum of the parts – but the behaviour of the parts themselves depends on the behaviour of the whole.

Like swarms of fireflies, all human societies are collective and coupled. Collective, meaning it is our combined behaviour that gives rise to society-wide effects. Coupled, in that our perceptions and behaviour depend on the perceptions and behaviour of others, and on the social and economic structures we collectively build. As consumers, we note a shortage of toilet paper at the supermarket, so we hoard it, and then milk, eggs and flour, too. We see our neighbours wearing masks, so put on a mask as well. Traders in markets panic upon perceiving a downward trend, follow the herd and, to echo Márquez, end up causing the precipitous drop they fear.

These examples capture how the collective results of our actions feed back, in both virtuous and vicious circles, to affect the system in its entirety – reinforcing or changing the patterns we initially perceived, often in nonobvious ways. For instance, some coronavirus contact-tracing apps can inform users of the locations of infected persons so they can be avoided. This kind of coupling between local behaviour and society-wide information is appealing because it seems to simplify decision-making for busy individuals. Yet we know from many years of work on swarming and synchronicity – think of the flashing fireflies – that the dynamics of coupled systems can be surprising.

A recent study in Nature Physics found transitions to orderly states such as schooling in fish (all fish swimming in the same direction) can be caused, paradoxically, by randomness, or ‘noise’ feeding back on itself. That is, a misalignment among the fish causes further misalignment, eventually inducing a transition to schooling. Most of us wouldn’t guess noise can produce predictable behaviour. The result invites us to consider how technology such as contact-tracing apps, although informing us locally, might negatively impact our collective movement. If each of us changes our behaviour to avoid the infected, we might generate a collective pattern we had aimed to avoid: higher levels of interaction between the infected and susceptible, or high levels of interaction among the asymptomatic.

Complex systems also suffer from a special vulnerability to events that don’t follow a normal distribution or ‘bell curve’. When events are distributed normally, most outcomes are familiar and don’t seem particularly striking. Height is a good example: it’s pretty unusual for a man to be over 7 feet tall; most adults are between 5 and 6 feet, and there is no known person over 9 feet tall. But in collective settings where contagion shapes behaviour – a run on the banks, a scramble to buy toilet paper – the probability distributions for possible events are often heavy-tailed. There is a much higher probability of extreme events, such as a stock market crash or a massive surge in infections. These events are still unlikely, but they occur more frequently and are larger than would be expected under normal distributions....