Substack cometh, and lo it is good. (Pricing)

The punctuated equilibrium of culture


John Winthrop, ~1600. Mitt Romney, 2008 – image credit, Jessica Rinaldi


Recently Megan Mcardle had a post up where she expressed curiosity as to why “futurists” circa 1900 had a tendency not to imagine revolutions in clothing style which might have been anticipated to occur over the next few decades. You also see see this in Star Trek in the 1960s, where faux-future fashion was clearly based on the trends of the day, from the beehive hair to miniskirts. So I thought this comment was of interest:

I don’t know the answer, but I don’t know that they were wrong to do it. Keeping fashions exactly the same as the present generally winds up with more in common with the actual future than deliberate “future” fashions. A fair number of men still wear ties, and on rare occasions a few even wear tailcoats; rather fewer wear silver jumpsuits.

There have been a few counters to extreme fashions in media SF: “Blade Runner”‘s lead wore the same trenchcoat as his noir forebears; “Babylon 5” went for modified business suits and moderate variations on military uniforms; the “Battlestar Galactica” reimagining was pretty much straight conservative turn-of-the-millennium wear despite being in a far different time. How have those worn versus the approach taken by “Star Trek” or the 2015 segment of the “Back to the Future” movies?

I’m not sure that I accept this case as airtight, but this is certainly true in the specifics. Though I just saw some clips of Running Man for the first time on Youtube, I viewed Blade Runner a few years back for the second time and was struck by how undated it was in regards to fashion sense. At least in a very noticeable manner. It got me to thinking of the nature of cultural evolution even then.


If you read this weblog with any closeness you know that I have a pretty orthodox skepticism of supra-individual level natural selection biologically. By this, I mean that the unit of selection above the level of the individual is often difficult to maintain because of the technical obstacles. To be concrete, consider that the vast majority of genetic variation between two adjacent human demes is to be found within them, not across them. As the power of selection is proportional to the genetic variance which it has to work with that means that lower level selective forces are far more powerful all things equal. All things are not always equal, so that doesn’t render higher level selection impossible, but it does load our die in terms of expectations.

But I think it is somewhat different when it comes to culture. As I said above most of the genetic variation between two spatially adjacent demes is partitioned within them, not across them. So it might be reasonable for allele A to have frequency of 45% in deme 1 and 55% in deme 2. There’s a difference, but you would probably not want to make inferences of a person’s identity in a particular deme by their allelic state.

Now move the toy model to culture. One can easily imagine language A having frequency of 95% in deme 1 and 5% in deme 2. Even accepting that most populations are at a dialect continuum so that this doesn’t mean that much, there will be cases when populations are verging upon another group which speaks a totally unintelligible language. The dialect of Ionia was different from that of Aeolia, but there was a clear and distinct difference between these Greek dialects and the languages of the Thracians. The term “barbarian” derives from the confused incomprehensible babbling of foreigners to Hellenes.

A real life example of the salience of culture and the relative triviality of genetics in selection would be what occurred in Southeastern Europe in the 1990s. The Serbs, Croats, and Bosniaks (Bosnian Muslims) emerged out of the same milieu of South Slavic tribes which pushed into the Balkans in the wake of the collapse of the Byzantine frontier in the 6th century. Their languages are mutually intelligible. But, because of religious differences these three groups have radically different cultural orientations. The Croats are Roman Catholics who face West. The Serbs are Orthodox Christians who turn to Russia. And the Bonsiak identity is a product of the Ottoman period, when a substantial fraction of South Slavs and Albanians converted to Islam but did not assimilate to a Turkish identity.

Massacres all across the former Yugoslavia were perpetrated based on cultural cohesion predicated on these tribal markers and civilizational affinities. The biological difference between these groups was marginal at best. The stark substantive religious difference between Serbs and Croats is far more recent than the original conversion to Christianity by the Western and Eastern Roman churches, because the chasm between what became Roman Catholicism and Eastern Orthodoxy really escalated in the medieval period and later the Ottoman years. As for the Bosniaks, they seem to have emerged out of an environment of marginal South Slavic highlanders within the last five centuries.

The power of culture to be buffeted by natural selection is contingent upon the ability of memes to rapidly homogenize and differentiate through conformity toward alternative norms. Differences once non-existent can quickly harden and seem eternal and inflexible. Biological evolution constrained by the parameters of Mendelian genetic inheritance is by nature somewhat more gradual and less protean.

I’ve been focusing on space, but why restrict it to that? The chart to the left shows what I have in mind: a change in the parameter of space or time when comparing two populations is only relevant if you’re talking about inter-demic competition. In purely descriptive terms they’re probably somewhat interchangeable. Imagine two groups which are basically disjoint on a quantitative cultural trait. I mean that they don’t overlap at all. To give an example, how about the number of times you have to pray per day. Population 1 could hold to a religion which suggests that 10 short prayers has the most merit, while population 2 adheres to a religion which asserts that 3 short prayers has the most merit. If you assume that religion is enforced top-down so that everyone in the population conforms, not anthropologically unrealistic, then one can conceive of a scenario where there are a few deviants, but the distributions don’t really overlap. The two populations occupy different locations, so there’s perfect correlation between cultural form and position in space. But the same can occur with time, as cultural forms evolve.

This is where punctuated equilibrium comes to mind. I’ve gone on the record as thinking this model is overrated. It’s a fine enough descriptor of the fossil record and change on the scale of eons, but I don’t see much mechanistic interest because I believe evolution is mostly scale independent. And yet I wonder if it might be a much more useful description for what happens to cultural forms. There are long periods of stasis and change on the margins, followed by radical breaks from the past. I have read that the standard business attire of elite males in the modern world derives from the suits preferred by Calvinist Northern Europeans. For various reasons I think this is an over simplification, but it seems obvious that phenotypically the modern man of power resembles a Roundhead more than a Cavalier in public. In fact the modern man resembles the 5th century Frank in trousers far more than the 3rd century Gallo-Roman in toga. The substantive distance in a trait value can be far greater over small notionally time periods because of the wild swings in the rate of cultural change.

The observation that the fossil record manifests discontinuities and shifts due to the coarseness of its measure of evolutionary change is interesting, but ultimately I don’t know how actionable it is in follow up projects. It’s a scaffold, not a pathway. But I do think that a better quantitative measure of the nature of cultural change can be very useful, because it can spotlight the “hinges of history.” In the past three generations it seems that the years from 1965-1970 were particularly important in all manner of ways. But is that so? And if it is so, why?

Posted in Uncategorized

Comments are closed.