Power laws, earthquakes, and war

On Boxing Day (December 26) 2004, a tsunami resulting from a 9.0+ magnitude earthquake killed about 250,000 people around the Indian Ocean. This was one of the deadliest natural disasters in recorded history. The Indian Ocean tsunami illustrated a major theme on this blog: the importance of catastrophes in human history, and in the history of life and the universe.

Earthquakes are one example of a phenomenon following a power law statistical distribution. The frequency of earthquakes drops off as an exponential function of their magnitude, so that on a logarithmic scale, the magnitude-frequency relationship looks linear. This is known as the Gutenberg-Ritter relation. (The deviation from linearity in the upper left part of the chart below may reflect measurement error, with a lot of tiny earthquakes not being detected.)

Power law distributions are found in many other contexts, for example, in the frequency of wars versus their magnitude (as measured by the number of war deaths). A power law distribution is very different from the more familiar bell-curve Gaussian normal distribution: extreme “black swan” events that are astronomically unlikely under a normal distribution may happen at appreciable frequency under a power law distribution. Depending on the exponent, a power law distribution may not have a well-defined variance, or even a well-defined mean.

For a technical discussion of why small scale processes sometimes aggregate to generate normally distributed outcomes, and other times aggregate to produce power law distributions, here’s an article on The common patterns of nature. A take home lesson – not always covered in introductory treatments of statistics and probability theory – is that catastrophes and extreme outcomes can be an expectable part of the natural order.

Steven Pinker and Nichlas Nassim Taleb have squabbled about the implications of all this for the probability of a peaceful future. Here’s a level-headed review. Several recent books carry this argument further. In Only the Dead: The Persistence of War in the Modern Age, Bear Braumoeller makes the case there is no good reason to think that war is in decline. Rather “international orders” – whether the nineteenth century Concert of Europe, or the post World War II liberal order – have often made for peace among participants and conflicts with non-participants. On the other side, in The Stupidity of War: American Foreign Policy and the Case for Complacency, John Mueller makes the case that the likelihood of war was and is greatly exaggerated, both during and after the Cold War, and argues for the virtues of complacency and appeasement. Of course this year’s Russian invasion of Ukraine forces us to revise our estimate of the probability of major war upward, but it doesn’t prove Pinker wrong: a snow storm in April doesn’t prove that March isn’t a wintrier month.

And here are a couple of blog posts from me about why the bloody early twentieth century was maybe more than just a run of bad luck.

The modern synthesis and the blank slate

August 1941 – November 1946

We’re now dividing time finely enough to include months as well as years.

For most of the later nineteenth century after the publication of On the Origin of Species. biologists were skeptical of Darwin’s proposed mechanism of evolutionary change – natural selection. It was only in the twentieth century that this began to change. When Mendel’s work on heredity was rediscovered in 1900, it was originally seen by many as antithetical to Darwinism. But with the pioneering theoretical work of Fisher, Haldane, and Wright, and the subsequent empirical work of Mayr, Dobzhansky, Simpson, Huxley, Stebbins, and others, Darwin’s theory of natural selection and Mendel’s theory of heredity were combined in what came to be called “the modern synthesis.” Julian Huxley’s book Evolution: The Modern Synthesis marked the coming of age of the theory.

In an earlier post I noted how Lyell’s and Darwin’s embrace of gradualism in explaining the past (as well as George Eliot’s celebration of Dorothea Brooke’s “unhistoric acts” and “hidden life”) had something to do with the political climate in England in the years after the French Revolution and Napoleon. Evolution: The Modern Synthesis was first published in 1942. It’s no surprise that the modern synthesis too was a product of its time, when Nazi Germany and the Soviet Union offered gruesome antithetical demonstrations of how not to think about evolution, genes, and behavior.

Not coincidentally, at the same time that biologists in England and the United States were advancing the modern synthesis, social scientists – cultural anthropologists, behaviorist psychologists – were coming to embrace a strong blank slate view of human nature. (Carl Degler tells the American side of the story in In Search of Human Nature: The Decline and Revival of Darwinism in American Social Thought.) There grew up something amounting to a peace treaty between evolutionary biology and the social sciences, with the two fields agreeing to respect each others’ spheres of influence. Social scientists would leave biology to the biologists, accepting, for example, that neither a good upbringing nor acquired skills can improve your genes. Biologists in turn would largely steer clear of addressing social behavior. For example, the theory of sexual selection, which Darwin developed, and Fisher elaborated, was mostly dropped from the modern synthesis as it matured. Huxley argued (pretty unconvincingly in retrospect) that the elaborate mating dances and ornaments found in so many species were not a product of sexual selection, but merely helped to get individuals to choose the right species of mate. Westermarck’s pioneering work on the evolutionary psychology of incest avoidance and the incest taboo was largely shelved in favor of the shakier theories of Freud and Lévi-Strauss. Even Darwin’s work on emotional expression, which might have seemed fairly anodyne politically, was largely rejected by anthropologists. And the study of prehistory was affected as well.

It was only beginning in the 1960s and 1970s, with the rise of sociobiology, that evolutionary biologists returned to seriously addressing social behavior. Sociobiology: The New Synthesis (1975), by E. O Wilson, made a nod to Huxley in its subtitle. It also announced the end of an intellectual peace treaty, and the opening of an intellectual war that persists up to the present.

And here is my obituary for E. O. Wilson, who died last year.

Culture wars

May 2016 – July 2017

Since 1981, the World Values Survey Association has been carrying out surveys around the world regarding people’s values, asking respondents, for example, whether most people can be trusted, and whether they are proud of their country. A lot of the variation in values across countries falls along two axes, call them Survival versus Well-Being/Self-Expression, and Traditional Authority versus Secular Rationality, shown as the x and y axes in the chart below.

In societies high on Survival and low on Well-Being/Self-Expression (left on the x axis), people tend be less trusting and less happy, and to value money and material well-being more than emotionally rewarding careers. In societies high on Traditional Authority (low on the y axis), people are more patriotic and more religious.

We can also plot countries around the world by their positions on the two axes, as in the chart below.

A few observations: Confirming everyone’s stereotypes, Sweden is extreme both in post-materialism, and in post-traditionalism. Overseas Europe is more traditional than the Continent: the Anglosphere is more traditional than the Continental Protestant world, and Latin America more traditional than the Continental Catholic world. And it looks like Soviet Communism did a moderately effective job of destroying traditional values, and a really good job of leaving people miserable.

Values change over time. They constitute a mediating link between economic and political change: economic changes tend to result in changing values, while changing values tend to result in changing political institutions. More specifically:

1. The growth of industrial employment tends to move societies up the y axis, away from traditional values, without shifting them much on the x-axis. The history of rapidly industrializing late nineteenth- and early-twentieth century Europe reflects this value shift, with new ideologies and leaders bypassing or assaulting traditional hierarchies of aristocracy and Church while fighting ruthlessly to make sure their followers came out on top in the struggle for existence.
2. More recent economic changes, toward post-industrial employment, tend to move societies rightward on the x axis. The declining levels of violence documented by Pinker, as well our halting progress toward a more democratic world, are reflections of this. These are encouraging developments, but matters are complicated by the fact that this movement is highly uneven, both across and within countries. We no longer see the stark divisions of the Cold War era. But in many areas around the world, people find themselves in a house divided against itself on cultural matters, and the resulting culture wars can make for more conflict. Political scientists have coined a label for this, Center-Periphery Dissonance, and many of the revolutionary political struggle of the last several years have pitted a modernizing center against a more traditional periphery.

Power laws, earthquakes, and war

On Boxing Day (December 26) 2004, a tsunami resulting from a 9.0+ magnitude earthquake killed about 250,000 people around the Indian Ocean. This was one of the deadliest natural disasters in recorded history. The Indian Ocean tsunami illustrated a major theme on this blog: the importance of catastrophes in human history, and in the history of life and the universe.

Earthquakes are one example of a phenomenon following a power law statistical distribution. The frequency of earthquakes drops off as an exponential function of their magnitude, so that on a logarithmic scale, the magnitude-frequency relationship looks linear. This is known as the Gutenberg-Ritter relation. (The deviation from linearity in the upper left part of the chart below may reflect measurement error, with a lot of tiny earthquakes not being detected.)

Power law distributions are found in many other contexts, for example, in the frequency of wars versus their magnitude (as measured by the number of war deaths). A power law distribution is very different from the more familiar bell-curve Gaussian normal distribution: extreme “black swan” events that are astronomically unlikely under a normal distribution may happen at appreciable frequency under a power law distribution. Depending on the exponent, a power law distribution may not have a well-defined variance, or even a well-defined mean.

For a technical discussion of why small scale processes sometimes aggregate to generate normally distributed outcomes, and other times aggregate to produce power law distributions, here’s an article on The common patterns of nature. A take home lesson – not always covered in introductory treatments of statistics and probability theory – is that catastrophes and extreme outcomes can be an expectable part of the natural order.

Steven Pinker and Nichlas Nassim Taleb have squabbled about the implications of all this for the probability of a peaceful future. Here’s a level-headed review. Several recent books carry this argument further. In Only the Dead: The Persistence of War in the Modern Age, Bear Braumoeller makes the case there is no good reason to think that war is in decline. Rather “international orders” – whether the nineteenth century Concert of Europe, or the post World War II liberal order – have often made for peace among participants and conflicts with non-participants. On the other side, in The Stupidity of War: American Foreign Policy and the Case for Complacency, John Mueller makes the case that the likelihood of war was and is greatly exaggerated, both during and after the Cold War, and argues for the virtues of complacency and appeasement.

And here are a couple of blog posts from me about why the bloody early twentieth century was maybe more than just a run of bad luck.

Learn This One Weird Trick (Part One)

… that humans use, and now you can too!

There are people who think that human beings are nothing special. Sure (the argument goes) people have uniquely large brains. But all sorts of creatures have unique features. Elephants are the only animals with trunks. Tamarins and marmosets are the only primates that give birth to twins. Platypuses are the only venomous mammals. Spotted hyenas are the only mammals whose females sport pseudo-penises (through which they give birth!). And so on. If we could ask members of these species they’d claim that they’re the special ones.

But of course we can’t ask them, and in any case, this isn’t a very convincing argument. Human beings have an absolutely outsize impact on the Earth, and the advent of human beings looks like one of the major evolutionary transitions, comparable in importance to the origin of the eukaryotic cell or multicellular life. But even if we buy this, it still leaves open the question of whether there’s a key adaptation – a One Weird Trick – that accounts for the exceptional course of human evolution. Here are some candidates that being are being batted around these days:

1) The cognitive niche. The basic idea is at least as old as Aristotle, that human brings are defined by their capacity for Reason. A modern version of this is advocated by evolutionary psychologist John Tooby and cognitive scientist Steven Pinker. Pinker in particular has elaborated the argument that humans are uniquely adapted to acquire and share knowledge, by virtue of a suite of cognitive, social, and linguistic adaptations. We’ve already touched on several aspects of this: Human beings seem to have taken the capacity for thinking about physical space and retooled it for thinking about the abstract cognitive space of possession – a social relationship. (Other abstract cognitive spaces include kinship, time, and change-of-state.) And humans seem to harness the machinery for processing the sounds of interacting solid objects in creating major categories of phonemes. For a more complete exposition, here’s an academic article by Pinker, and a talk on youtube.

2) Culture. Rob Boyd and Pete Richerson, who’ve done a lot of mathematical modeling of cultural evolution, are skeptical about the “cognitive niche” argument. Too much culture, they argue, is things that have been learned by trial-and-error, and are passed on from one generation to the next without people understanding why they work. Boyd and Richerson appeal, as anthropologists have for generations, to the importance of culture. We mentioned earlier their argument that the frequency of climate change in the Ice Age was nicely calibrated to favor social learning rather than individual learning or instinct. Joseph Henrich provides a recent defense of the importance of culture. Contra Pinker, he thinks humans often don’t have a good cause-and-effect understanding of the things they do, but depend heavily on imitation and the accumulated wisdom of the elders. And see this post, for the importance of High Fidelity cultural transmission in the evolution of animal and human intelligence.

Coming up: Part Two. Recursion and Shared Intentionality

My handaxe

1,043 – 986 thousand years ago

By today’s date, Acheulean tools are well developed in Africa, and found in India too. Sophisticated tools like the Acheulean hand axe probably tell us something not just about cognition in relation to tool making, but also about social cognition. You wouldn’t make a hand axe, use it, and abandon it. Nor would you go to all the trouble if the biggest, baddest guy in the group was immediately going to grab it from you. So there is probably some notion of artifacts-as-personal-possessions by the time Acheulean appears.

Possession is a social relationship, a relationship between two or more individuals with respect to the thing possessed. Robinson Crusoe didn’t “own” anything on his island before Friday came along.

Linguists have noted something interesting about the language of possession that maybe tells us something about the psychology of possession: Expressions for possession are often similar to expressions for spatial locations. Compare spatial expressions:

João went to Recife.
Chico stayed in Rio.
The gang kept Zezinho in Salvador.

and corresponding constructions for possessions:

The Crampden estate went to Reginald.
The Hampden estate stayed with Lionel.
Thag kept axe.

Of course the Crampden estate didn’t go anywhere in physical space, but it still traveled in the abstract social space of possession. In some cases just switching from inanimate to animate subject will switch the meaning from locative to possessive. The Russian preposition y means at/near when applied to a place (People are at Nevsky street) but possession when applied to a person (Hat is “at” Ivan = Ivan has hat.)

What may be going on here: people (and many other creatures) have some mental machinery for thinking about physical space. That machinery gets retooled/borrowed/exapted for thinking about more abstract relationships. So the cognitive psychology of space gets retooled for thinking about close and distant social relationships, or time ahead and behind. In other words, we may be seeing a common evolutionary phenomenon of organs evolved for one purpose being put to another purpose – reptile jaw bones evolve into mammalian inner ear bones, dinosaur forelimbs evolve into bird wings. You can find Steve Pinker making this argument in his book The Stuff of Thought. And Barbara Tversky’s recent Mind in Motion: How Action Shapes Thought seems to make the argument at greater length. For a while most of the evidence of repurposing spatial cognition for more abstract relationships came from linguistics, but there’s now some corroboration from neurology.

And I’ve made the argument for the particular case of kinship: regularities in kin terminology across cultures tell us something about pan-human ideas of “kinship space.” (My kin and mybody parts are arguably the most basic, intrinsic primitive sorts of possessions, since long before my handaxe.) This implies that the evolutionary psychology of kinship has not just an adaptive component (adaptations for calculating coefficients of relatedness and inbreeding), but also a phylogenetic component  (homologies with the cognitive psychology of space).

We’ll see other possible examples, involving e.g. the evolution of speech sounds, as we move along.

Culture wars

August 2016 – September 2017

Since 1981, the World Values Survey Association has been carrying out surveys around the world regarding people’s values, asking respondents, for example, whether most people can be trusted, and whether they are proud of their country. A lot of the variation in values across countries falls along two axes, call them Survival versus Well-Being/Self-Expression, and Traditional Authority versus Secular Rationality, shown as the x and y axes in the chart below.

In societies high on Survival and low on Well-Being/Self-Expression (left on the x axis), people tend be less trusting and less happy, and to value money and material well-being more than emotionally rewarding careers. In societies high on Traditional Authority (low on the y axis), people are more patriotic and more religious.

We can also plot countries around the world by their positions on the two axes, as in the chart below.

A few observations: Confirming everyone’s stereotypes, Sweden is extreme both in post-materialism, and in post-traditionalism. Overseas Europe is more traditional than the Continent: the Anglosphere is more traditional than the Continental Protestant world, and Latin America more traditional than the Continental Catholic world. And it looks like Soviet Communism did a moderately effective job of destroying traditional values, and a really good job of leaving people miserable.

Values change over time. They constitute a mediating link between economic and political change: economic changes tend to result in changing values, while changing values tend to result in changing political institutions. More specifically:

1. The growth of industrial employment tends to move societies up the y axis, away from traditional values, without shifting them much on the x-axis. The history of rapidly industrializing late nineteenth- and early-twentieth century Europe reflects this value shift, with new ideologies and leaders bypassing or assaulting traditional hierarchies of aristocracy and Church while fighting ruthlessly to make sure their followers came out on top in the struggle for existence.
2. More recent economic changes, toward post-industrial employment, tend to move societies rightward on the x axis. The declining levels of violence documented by Pinker, as well our halting progress toward a more democratic world, are reflections of this. These are encouraging developments, but matters are complicated by the fact that this movement is highly uneven, both across and within countries. We no longer see the stark divisions of the Cold War era. But in many areas around the world, people find themselves in a house divided against itself on cultural matters, and the resulting culture wars can make for more conflict. Political scientists have coined a label for this, Center-Periphery Dissonance, and many of the revolutionary political struggle of the last several years have pitted a modernizing center against a more traditional periphery.

Power laws, earthquakes, and war

May 2004 – February 2006

On Boxing Day (December 26) 2004, a tsunami resulting from a 9.0+ magnitude earthquake killed about 250,000 people around the Indian Ocean. This was one of the deadliest natural disasters in recorded history. The Indian Ocean tsunami illustrated a major theme on this blog: the importance of catastrophes in human history, and in the history of life and the universe.

Earthquakes are one example of a phenomenon following a power law statistical distribution. The frequency of earthquakes drops off as an exponential function of their magnitude, so that on a logarithmic scale, the magnitude-frequency relationship looks linear. This is known as the Gutenberg-Ritter relation. (The deviation from linearity in the upper left part of the chart below may reflect measurement error, with a lot of tiny earthquakes not being detected.)

Power law distributions are found in many other contexts, for example, in the frequency of wars versus their magnitude (as measured by the number of war deaths). A power law distribution is very different from the more familiar bell-curve Gaussian normal distribution: extreme “black swan” events that are astronomically unlikely under a normal distribution may happen at appreciable frequency under a power law distribution. Depending on the exponent, a power law distribution may not have a well-defined variance, or even a well-defined mean.

For a technical discussion of why small scale processes sometimes aggregate to generate normally distributed outcomes, and other times aggregate to produce power law distributions, here’s an article on The common patterns of nature. A take home lesson – not always covered in introductory treatments of statistics and probability theory – is that catastrophes and extreme outcomes can be an expectable part of the natural order.

Steven Pinker and Nichlas Nassim Taleb have squabbled about the implications of all this for the probability of a peaceful future. Here’s a level-headed review. Several recent books carry this argument further. In Only the Dead: The Persistence of War in the Modern Age, Bear Braumoeller makes the case there is no good reason to think that war is in decline. Rather “international orders” – whether the nineteenth century Concert of Europe, or the post World War II liberal order – have often made for peace among participants and conflicts with non-participants. On the other side, in The Stupidity of War: American Foreign Policy and the Case for Complacency, John Mueller makes the case that the likelihood of war was and is greatly exaggerated, both during and after the Cold War, and argues for the virtues of complacency and appeasement.

And here are a couple of blog posts from me about why the bloody early twentieth century was maybe more than just a run of bad luck.

The modern synthesis and the blank slate

November 1939 – February 1945

We’re now dividing time finely enough to include months as well as years.

For most of the later nineteenth century after the publication of On the Origin of Species. biologists were skeptical of Darwin’s proposed mechanism of evolutionary change – natural selection. It was only in the twentieth century that this began to change. When Mendel’s work on heredity was rediscovered in 1900, it was originally seen by many as antithetical to Darwinism. But with the pioneering theoretical work of Fisher, Haldane, and Wright, and the subsequent empirical work of Mayr, Dobzhansky, Simpson, Huxley, Stebbins, and others, Darwin’s theory of natural selection and Mendel’s theory of heredity were combined in what came to be called “the modern synthesis.” Julian Huxley’s book Evolution: The Modern Synthesis marked the coming of age of the theory.

In an earlier post I noted how Lyell’s and Darwin’s embrace of gradualism in explaining the past (as well as George Eliot’s celebration of Dorothea Brooke’s “unhistoric acts” and “hidden life”) had something to do with the political climate in England in the years after the French Revolution and Napoleon. Evolution: The Modern Synthesis was first published in 1942. It’s no surprise that the modern synthesis too was a product of its time, when Nazi Germany and the Soviet Union offered gruesome antithetical demonstrations of how not to think about evolution, genes, and behavior.

Not coincidentally, at the same time that biologists in England and the United States were advancing the modern synthesis, social scientists – cultural anthropologists, behaviorist psychologists – were coming to embrace a strong blank slate view of human nature. (Carl Degler tells the American side of the story in In Search of Human Nature: The Decline and Revival of Darwinism in American Social Thought.) There grew up something amounting to a peace treaty between evolutionary biology and the social sciences, with the two fields agreeing to respect each others’ spheres of influence. Social scientists would leave biology to the biologists, accepting, for example, that neither a good upbringing nor acquired skills can improve your genes. Biologists in turn would largely steer clear of addressing social behavior. For example, the theory of sexual selection, which Darwin developed, and Fisher elaborated, was mostly dropped from the modern synthesis as it matured. Huxley argued (pretty unconvincingly in retrospect) that the elaborate mating dances and ornaments found in so many species were not a product of sexual selection, but merely helped to get individuals to choose the right species of mate. Westermarck’s pioneering work on the evolutionary psychology of incest avoidance and the incest taboo was largely shelved in favor of the shakier theories of Freud and Lévi-Strauss. Even Darwin’s work on emotional expression, which might have seemed fairly anodyne politically, was largely rejected by anthropologists. And the study of prehistory was affected as well.

It was only beginning in the 1960s and 1970s, with the rise of sociobiology, that evolutionary biologists returned to seriously addressing social behavior. Sociobiology: The New Synthesis (1975), by E. O Wilson, made a nod to Huxley in its subtitle. It also announced the end of an intellectual peace treaty, and the opening of an intellectual war that persists up to the present.

Learn This One Weird Trick … (Part One)

… that humans use, and now you can too!

There are people who think that human beings are nothing special. Sure (the argument goes) people have uniquely large brains. But all sorts of creatures have unique features. Elephants are the only animals with trunks. Tamarins and marmosets are the only primates that give birth to twins. Platypuses are the only venomous mammals. Spotted hyenas are the only mammals whose females sport pseudo-penises (through which they give birth!). And so on. If we could ask members of these species they’d claim that they’re the special ones.

But of course we can’t ask them, and in any case, this isn’t a very convincing argument. Human beings have an absolutely outsize impact on the Earth, and the advent of human beings looks like one of the major evolutionary transitions, comparable in importance to the origin of the eukaryotic cell or multicellular life. But even if we buy this, it still leaves open the question of whether there’s a key adaptation – a One Weird Trick – that accounts for the exceptional course of human evolution. Here are some candidates that being are being batted around these days:

1) The cognitive niche. The basic idea is at least as old as Aristotle, that human brings are defined by their capacity for Reason. A modern version of this is advocated by evolutionary psychologist John Tooby and cognitive scientist Steven Pinker. Pinker in particular has elaborated the argument that humans are uniquely adapted to acquire and share knowledge, by virtue of a suite of cognitive, social, and linguistic adaptations. We’ve already touched on several aspects of this: Human beings seem to have taken the capacity for thinking about physical space and retooled it for thinking about the abstract cognitive space of possession – a social relationship. (Other abstract cognitive spaces include kinship, time, and change-of-state.) And humans seem to harness the machinery for processing the sounds of interacting solid objects in creating major categories of phonemes. For a more complete exposition, here’s an academic article by Pinker, and a talk on youtube.

2) Culture. Rob Boyd and Pete Richerson, who’ve done a lot of mathematical modeling of cultural evolution, are skeptical about the “cognitive niche” argument. Too much culture, they argue, is things that have been learned by trial-and-error, and are passed on from one generation to the next without people understanding why they work. Boyd and Richerson appeal, as anthropologists have for generations, to the importance of culture. We mentioned earlier their argument that the frequency of climate change in the Ice Age was nicely calibrated to favor social learning rather than individual learning or instinct. Joseph Henrich provides a recent defense of the importance of culture. Contra Pinker, he thinks humans often don’t have a good cause-and-effect understanding of the things they do, but depend heavily on imitation and the accumulated wisdom of the elders. And see this post, for the importance of High Fidelity cultural transmission in the evolution of animal and human intelligence.

Coming up: Part Two. Recursion and Shared Intentionality