The plague riot in Moscow, 1771.
This morning, in a break during Sky News, I saw an ad for a smartphone with the tagline, "Connecting People". It took a rather darker meaning than it had before the weekend.
Riots have been with us as long as cities. When you gather hundreds of thousands or millions of people in one densely populated area, it's inevitable that order will break down from time to time. The real miracle is that it happens so rarely.
After all, we know that human beings are imitative creatures - we pick up on what others are doing naturally and easily and often unthinkingly. Patterns of behaviour spread like contagions through populations, whether it's a hairstyle or a way of talking - or something less benign. Suicide experts have documented the spikes in suicide rates that occur when high profile suicides are committed - there was a 12% rise in the U.S suicide rates following the death of Marilyn Monroe.
Rioting is imitative behaviour compressed and sped up. The people who study crowds will tell you that such behaviour is massively complex: it involves individuals with their own internal motivations reacting to groups, and groups reacting to the actions of individuals, and everything happening very fast. It's top-down and bottom-up, each feeding off the other. So it's always difficult to discern 'root causes' because these things taken on a momentum of their own. But the current riots do seem peculiarly rootless compared to previous outbreaks, like the Broadwater Farm riots, when the grievances seemed clearer and more tangible.
Violent behaviour doesn't spread easily. In cities like London where security is relatively light touch - with roughly 200 people for every police officer - order relies on a kind of invisible contract among the people that live there. That's the basis of any community. It also relies on fear of punishment or public shaming. When people float free of the felt, tactile, social bonds of a community, they become more subject to influence from outside it.
Three hundred years ago, before the birth of modern media, there wasn't much 'outside' the community - not in the sense of information or social cues that could be instantly communicated. So when people rioted it was because there was some social problem that had been festering for a while and then explodes, tearing the whole community apart. The violence rose up from within. Even thirty or twenty years ago, there were only newspapers and TV news bulletins bringing news from elsewhere, at daily or hourly intervals, to the world.
These days, of course, we have mobile phones, instant messaging, social networks and 24-hour news. So the madness of a febrile crowd can spread faster and further and with more fluidity than ever before. People's imitative instincts, always present, can overwhelm their common sense and moral reasoning. The frontal cortex - the seat of our self-restraint - is like an inadequate flood barrier during a heavy rainstorm.
We may be seeing a new strain of mass behaviour, one that results from the meeting of two factors, one social and the other technological. On the one hand, large numbers of people who are floating free from wider communities and who are thus both less bound by their norms and more vulnerable to influence from people with whom they have no enduring relationship. On the other, technologies that instantly transmit information to participants about what others are doing, supercharging the feedback loops and obliterating their sense of individual responsibility.
When you're not part of a community you are more likely to join the herd.