Where culture goes to die

By D.J.P.

C.P. SNOW would have been heartened. The scientist and author alleged in the 1950s that intellectual progress in the whole of the Western world had become neatly and resolutely divided between the sciences and the humanities. But in research profiled in Science this week, those "two cultures" have come crashing together, with results that are both numerically intriguing and, fittingly, pleasing to the eye.

Maximilian Schich, of the University of Texas at Dallas, and colleagues elsewhere in America and Switzerland, set their sights on infiltrating one of Snow's cultures with the other. They brought network science—a mode of analysis that is less about the "what" and the "who", and much more about the "with whom"—to bear on cultural migration in the Western world.

Their starting point was data painstakingly acquired from diverse sources: the locations and dates of the births and deaths of more than 150,000 notable individuals, stretching back through 2,000 years of history. By tracking where great artists and thinkers were and where they went, the team could discern not only patterns of migration but also the rise and fall of cultural centres. (In the illustrations, blue represents a place of birth, and red the location of death.)

The findings seem to verify a number of empirical rules first worked out by Ernst Georg Ravenstein, a German geographer who noted patterns within the migrations he saw in the late 19th century: most migrants do not go very far, those who do aim for big cities, urban centres grow from immigration far more than procreation, and so on. In the new study, these rules are borne out not just over the time since then, but as far back as the data go—the better part of a millennium.

The work contained some genuine surprises as well. Despite the ease and frequency with which travellers move in modern times, the median distance between birth and death rose by less than a factor of two between the 14th and the 21st centuries. Globalisation, it seems, has not much magnified the natural human propensity to be on the move.

While we might think of some cities as the beating hearts of culture since their very inception, the team's results showed otherwise. The popularity of destinations such as Paris, Florence, New York and Vienna waxed and waned fitfully through the centuries, in a way more mercurial even than modern cultural markers such as Twitter hashtags (network science has looked at those too).

Some cities emerged from the data as what the authors poetically note as "birth sources" or "death attractors"—Brooklyn seems to have produced quite a few notables but not seen their deaths, and Hollywood had more than 10 times as many deaths as births. One might opine that Hollywood is where culture goes to die.

Of what use, then, are all these beautiful, multicoloured maps of cultural movement? They represent the idea that "we can do the same thing in cultural history that we can do in biology", as Dr Schich puts it. With the right data in hand, what might have been armchair musings about cultural matters can be solidified, quantified, presented graphically and perhaps even made predictive.

"The non-scientists have a rooted impression that the scientists are shallowly optimistic, unaware of man's condition," Dr Snow argued in his lecture of legend. What seems clear is that Dr Schich and his colleagues are deeply optimistic that awareness of man's condition is both in scientists' sights, and within their grasp.