Order Without Law, Robert Ellickson

Robert Ellickson's Order Without Law is a study, as its sub-title says of "How Neighbors Settle Disputes". Ellickson starts with a deep dive into how ranchers and farmers in Shasta County, in the rural northern part of California actually deal with a problem that Richard Coase brought up in a classic paper on transactions costs. In "The Problem of Social Cost", Coase argued that if transaction costs were irrelevant, it wouldn't matter how property rights were allocated. Regardless of whether ranchers were responsible for keeping their cattle from straying or farmers were responsible for keeping unwelcome beasts out of their crops, the same solutions would be reached. If the law doesn't allocate responsibility to the low cost actor, then according to Coase the other party would find a way to pay the other party to do the cheaper thing. Of course, most of the argument since then has focused on the fact that transaction costs are seldom negligible.
Ellickson says that Shasta County is uniquely positioned for a study on this issue

Shasta County is "open range." In open range an owner of cattle is typically not legally liable for damages stemming from his cattle's accidental trespass upon unfenced land. Since 1945, however a special California statute has authorized the Shasta County Board of Supervisors, the county's elected governing body, to "close the range" in subareas of the county. A closed-range ordinance makes a cattleman strictly liable (that is liable even in the absence of negligence) for any damage his livestock might cause while trespassing within the territory described by the ordinance. The Shasta County Board of Supervisors has exercised its power to close the range on dozens of occasions since 1945, thus changing for selected territories the exact rule of liability that Coase used in his famous example.

This is the kind of change that economists love to study, because they can look at how behavior changes over time and treat the change of law as an independent variable. Any consistent changes in people's activity after the law changes can be treated as the result of the legal change.Ellickson focuses on how neighbors actually respond when trespasses occur. The book is filled with colorful stories giving details of what happened when particular responsible or irresponsible ranchers allowed their livestock to wander. The main observation is that while people were generally aware whether their property was in 'open' or 'closed' lands, their resolutions to incidents had little to do with what the law called for and more to do with a commonly accepted wisdom about that cattle owners are morally responsible for the damage. According to Ellickson, this fits Coase's model, since cattle owners are the low-cost provider. There are a variety of different types of pasture throughout Shasta County, and the cattle owners know more about how densely they are using any particular piece, and are more aware of which neighbors are most sensitive to their intrusions.
One of the most important enforcement mechanisms that Ellickson cites is plain simple gossip. Most of the people he talks about are eager to make things right, rather than be the subject of their neighbors' pointed comments. There is one member of the community who gets discussed a lot, but there are more extreme measures available when there are repeated run-ins, and one party is a consistent non-cooperator.
Ellickson is a good story teller and an astute observer. While the subjects of his study are less tight-knit than the farmers Ostrum described, there is enough social cohesion so that norms develop, and neighborliness is for the most part, a stronger limitation on people's interactions than actual laws.




0.3productChris Hibbert

The Secret of our Success, by Joseph Henrich

Joseph Henrich's The Secret of Our Success has a fair amount of overlap with Herculano-Houzel's The Human Advantage, which I reviewed in July. Both spend most of their attention on explaining why humans, of all the products of evolution, turned out to be the smartest and hence dominant species on the planet. The Human Advantage focused on what makes the human brain unique, and found some surprising neuronal traits that sets mammals apart from other other animals, and that make primates unique among mammals in their neuronal architecture. Henrich, on the other hand, takes pains to point out that individual humans (even very smart ones) aren't very good at figuring out how to survive in new environments. He uses that evidence to argue that communication and culture make the difference. As individuals, he claims, we aren't much smarter than other primates.

They both agree that cooking was a huge step forward for us, but Henrich takes pains to point out that this only an advantage when we're raised in a cultural group. Unlike practically all other animals, we don't instintively know how to unlock the nutrition in common foodstuffs—without training, it would take a long time (during which you have to be subsisting on something else) to figure out how to prepare most of what we eat.

The book starts out with several stories about lost european explorers becoming stranded, and if they didn't get help from locals, they would starve in the midst of what the locals would consider plenty. In Australia, the Arctic, and Florida, well-funded and trained explorers slowly starved because they couldn't figure out how to find, harvest, or prepare the foods the locals subsisted on, and they either didn't think to ask for help, or they drove away those who tried to help them. In contrast, there are a couple of stories of individual aborigines who are separated from their kin, and do just fine for years, since they grew up gathering and preparing the local bounty. His point is that our strength, as a species, is learning from one another, and picking up on every small increment in survivability.

I've been saying for years (since reading Jared Diamond's Guns, Germs, and Steel) that the thing to realize about the spread of humans and their ability to make use of local flora and fauna is that there were enough people, and people are curious enough that we tried to exploit everything, and we tried to make use of everything available in all conceivable ways. How else to explain the fact that people ate acorns, seal livers, and nardoo. In preparing nardoo, the Australian aborigines grind seeds, leech them with water, mix them with ash during heating, and use mussell shells to serve them. If you miss any step, then like the explorers, you'll die of poisoning or stavation with a full belly.

Along the way, this book has lots of interesting proposals about how culture affects prestige and dominance in ways that make it possible for us to live in larger groups and take advantage of the skills and abilities of more people; how competition for living space between groups leads to cultural differences, and how our ability and drive to share culture and learn from each other leads to increasing communication abilties and common grammar strength across the species. There are interesting tidbits spread throughout.

In talking about how living in larger groups with a larger repertoire of tools and techniques make us more capable without requiring more individual smarts or inventiveness, Henrich gave a list of simple tools that is more interesting than the standard list of 6 simple machines known since antiquity:

wheels, pulleys, springs, screws, projectiles, elastically stored energy (e.g. bows, spring traps), levers, poisons, compressed air (blow guns), rafts, leisters [a barbed spear], and heating (fire and coooking).

Instead of focusing on mechanical advantage as we do with the simple machines, this focuses on shared, reusable knowledge, and shows that there were ideas around to be re-used even in societies that were very primitive by modern standards.

Henrich has a longer more detailed time-line than Herculan-Houzel, and his focuses on evidence about tool use showing accumulation of culture rather than archeological evidence relating to brain size, cooking, and gut size. I enjoyed this book as much as Human Advantage, and it added an interesting, non-conflicting story about the roots of our intelligence. It didn't feel as if it has as much relevance to the question about our place in the universe—once we set out on the path toward communication and shared culture, Henrich didn't mention further roadblocks toward increasing advantage as we exploited the new niche better.

0.3productChris Hibbert

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Chris Hibbert

Suzana Herculano-Houzel's The Human Advantage is a good book with some important insights hidden behind a fairly dry and dense presentation on "how I made these important discoveries." Herculano-Houzel (by her own account) pioneered a technique for determining the number of neurons in brain tissue, and managed (through a fair number of mildly interesting adventures) to bring together samples of many different primate, rodent, and other mammalian brains in order to work out the scaling laws that govern how brains and neuron counts grow with body mass in different tissues across different lineages. She shows a lot of graphs and charts to demonstrate that (with two exceptions) for most mammals, neuron counts scale up with an exponent of .5 with body mass, but in primates, the scaling factor is .8. If neurons have to be added in order to increase intelligence, this means that primates have a huge advantage. In order to get smarter, brains and neuron count have to increase. Larger bodies are necessary in order to sustain a larger brain, and if neuron count or neuron density is the limiting factor in intelligence, then you want to be able to pack more neurons into a denser brain in order not to require an enormous body.

Once Herculano-Houzel has established the basic scaling laws, she delves into the economics of maintaining a sufficiently neuron rich brain. The comparative scaling laws mean that as you look at bigger and bigger species of mammals, the neuron counts increase with the square root of the body mass. As primate species get larger, their neuron count increases much more quickly, which means that for a given body size, a primate is capable of supporting a larger brain than would a mammal. The cross-over point where the two lineages have comparable neuron sizes are with body sizes in the 10 gram range. At any larger size, if you compare a primate with another similar sized mammal, the primate is probably smarter.

There is a separate literature showing the energy requirements for many particular species. Herculano-Houzel used her new numbers on neurons for rodent and primate species to show that there is a direct correlation between the number of neurons and the amount of glucose consumed per minute by the brain. For humans (and others in the Homo lineage, being able to take advantage of the primate scaling laws gives a big boost, but you still have to find a way to ingest sufficient calories to afford the bigger brain.

Humans have two main advantages on this score compared to other primates. Walking on two legs is much more energy efficient than knuckle-walking like other (primarily arboreal) primates or on four legs. This increases the range over which foragers could range, and also freed up hands for gathering and carrying. It's not clear what originally drove bipedalism in the homo line, but it occurs at the same branch point that leads to the massive growth in cranial capacity.

The other big human advantage is cooking. I've seen discussions before that cooking increases the efficiency of digestion, and led to our shorter digestive tract, which allowed us to switch energy resources from digestion to our brains, but Herculano-Houzel points out that even before control of fire, other kinds of preparation (chopping and mashing for example) reduce the energy required for digestion. The anthropological evidence for food preparation goes back much further than the evidence of cooking, and significantly after bipedalism. The earliest evidence of eating meat is swiftly followed by anatomic adaptations to a more efficient diet, which is quickly followed by better tools, and the then bigger brains. Part of the evolutionary adaptation for bigger brains included smaller jaws.

Evidence of tool use and manufacture date back to 3.3 MYA (Million Years Ago). This date was recently pushed back from 2.6 MYA. These tools were simple flint knives. Archaeologists wouldn't count rocks that were used for pounding, since they are impossible to distinguish from unworked rocks. The flint knives would have been useful for cutting up meat, which would make it more digestible, and is necessary in order to survive with smaller jaws. Presumably, eating primitively processed foods had to become habitual before later evolutionary steps that relied on it would have survived in the population. The archaeological evidence gives the following timeline:

1. 4.4 MYA: bipedalism appears
2. 3.3 MYA: earliest tool use
3. 2.5 MYA: eating meat
4. 2.4 MYA: beginning of the reduction in size of the jaw
5. 1.9 MYA: smaller gut is clearly present
6. 1.7 MYA to 300 KYA: The Acheulean hand axe
7. 1.5 MYA-100 KYA: start of the increase in cranial capacity
8. 1 MYA: Clear indications of cooking

Another tantalizing clue is that the taste for cooked food may pre-date adoption of the habit. Herculano-Houzel refers to two studies that show that chimpanzees have a very strong preference for the taste of cooked food over raw. I don't know whether this has been investigated in other lineages, but if so, (even if it's just the body innately being able to detect foods that are provide big efficiency gains) it provides a boost for any lineage that can figure out how to reliably prepare foods--once you start, it would be an easy habit to keep, providing that the right food sources and tools are accessible.

Earlier, I mentioned that there are two exceptions to the laws regulating the number of neurons in primates and in all other mammals. The first is gorillas, which have brains and neuron counts much closer to those of other mammals rather than those expected of a primate. This fact about gorillas has been throwing off the results of previous researchers, who could only measure brain capacity. They concluded that the rules for primates would be the same as for other mammals, and argued that it was humans that were outliers. Once you plot the detailed data from small and medium primates and compare to mammals, it's easy to see a different trend line applies, and that humans fit on the primate line and gorillas do not. The other exception is elephants. (Herculano-Houzel has an entertaining section about her adventures getting elephant brains to analyze.) Elephants have brains whose size follows the standard scaling rule for mammals. They're huge, and they have huge brains. But their neurons are distributed very differently from all other species. 98% of the neurons are in the cerebellum, while the normal number doesn't get much above 80%. So elephants have big brains and a lot of neurons, but this explains why they're not even smarter than us, presuming neurons in the cerebral cortex are the thing that matters most.

Anyway, the later clues about cooking and bipedalism only added to my reaction that this work may provide an improved answer to the Fermi paradox. Herculano-Houzel doesn't appear to have data about the brains of animals beyond mammals, but if all the mammals outside of primates share a common scaling factor, then that's an indication that it's hard to evolve intelligence given the standard energy budget. It takes a special trick (which didn't have an immediate obviously benefit in the small primates in which it evolved) which was only discovered in one previously obscure branch of the mammal family tree to enable the efficient scaling that allows bodies to grow large enough to support brains supporting enough neurons to enable tool use. This enables (with other accidents like bipedalism and prepared food appearing in the same lineage) the feedback cycle that led to our massive growth in intelligence.

I've never been very worried by the argument that says the Fermi paradox indicates that there's a Great Filter, and if we can't figure out what the hard step was in our past, we should expect to encounter a hurdle in our future that has stopped other species from getting to space. The Human Advantage makes me even more sanguine. It's hard to evolve an intelligent species. There are a lot of happy accidents in our past, and the likely number of extra-terrestrial species in our light cone may be smaller than we thought. It would be nice to see more data showing the scaling laws that apply outside the primates (and in the cetaceans, which she didn't give much data about). I'll be surprised if any of them show divergent scaling progression compared to baseline mammals.

Steven Pinker: The Better Angels of Our Nature

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Chris Hibbert

Steven Pinker's The Better Angels of our Nature argues that violence has been declining over the last several centuries, and continues to decline, even though the common wisdom seems to say the opposite. Pinker marshalls an enormous quantity of data to buttress his story, and fills in with enough explanation to make a very convincing case. At the end, he tries to explain this long term trend, and comes up with several mechanisms, but since this section is less data driven, it's less convincing than the fact that the change is broad, pervasive, and has continued for a very long time.

Pinker starts out with wars, genocide, and other large scale killings. He amasses a dataset of all known mass killings before the modern age. The data is spotty, so it's hard to draw many conclusions, but it is clear that the distant past included its share of conflicts resulting in lots of deaths, and the twentieth century's war are memorable more for their recency than their scale. In addition, there's a pretty clear trend that the great power conflicts of the early twentieth have disappeared. At the end of his chapter on the Long Peace, Pinker points out that since the end of WWII there have been zero:

1. nuclear weapons used
   
2. battlefield fights between great powers
   
3. armies crossing the Rhine (longest interval since 200 BCE)
   
4. wars between european states
   
5. wars between developed countries anywhere in the world
   
6. territorial expansions by conquest for a developed country
   

As we're getting close to 50 or 60 years without a conflict between major powers, it becomes more plausible that it's a trend rather than an aberration.

From large-scale conflicts, Pinker moves on to socially-approved violence, and then to individual violence. Socially-approved violence includes things like slavery and wide-spread repression as of jews and gays as well as public execution and public torture and punishment. All these have gone from common to unacceptable over the long term. Pinker shows that, in parallel with granting rights to more and more groups the statistics on personal violence in a very broad range of contexts have been declining. Historic attitudes toward blacks, women, gays, ethnic groups, children, and animals have all changed dramatically.

Finally, Pinker tries to figure out what's been driving this change. He starts out by describing some broad trends: The Long Peace, and The Rights Revolution, but he admits they're just names, not a description of causes. From there he looks for factors that could have caused these trends. Empathy may have been increased because of the spread of literacy and mass entertainment that give us more access to other points of view. Self control, likewise may have been improved by the promulgation of personal habits that enable people to make their short-term desires subservient to their longer-range goals. He considers biological evolution, but concludes that while it would have been capable of producing a change, we don't have any evidence for the hypothesis. Next Pinker discusses whether humanity's moral sense or rationality has improved in some way to produce the improvement. He accepts that people are getting smarter (i.e. "the Flynn effect") and argues that once we reach a certain level, we can use reason to see that cooperation is more in our interest than violence, first at the personal level, and gradually at broader levels on interaction.

Finally, Pinker presents a framework for thinking about how various changes have impacted people's incentive structures, and what consequences they have for interactions. It's all based on the basic prisoner's dilemma payoff matrix, showing the options two parties face when they can make independent choices as they interact. The first version is called the Pacifist's dilemma, and shows that wars and fights are costly, but it's better to be the aggressor than the defeated. A second shows that "Leviathan" (a government) can change everyone's incentives by penalizing agression. Next is a chart showing that trade ("Gentle Commerce") improves things for everyone by improving the payoffs as long as agression is avoided. His final chart assumes that empathy and reason are added in, and everyone feels not only their own gains and losses, but those of the other party as well. At that point only positive sum outcomes make sense, since each player gains no advantage by imposing costs that are felt by both sides.

This model is plausible, but not compelling. Something like this might be going on, but it's hard to say that he's actually found the mechanism driving things. An interesting postscript is provided by Nassim Nicholas Taleb, who argues that Pinker doesn't understand the statistics of the fat tail that Taleb has been writing about for a while. If the proper curve is not a normal distribution, but instead a fat-tailed curve with most of the weight in the extremes, then the stats demonstrating that there is an effect to be explained are worthless. Taleb gives a bunch of (not well-explained) possible mechanisms for supposing that Pinker might have missed something, but he doesn't analyze whether the historical data looks more like a normal distribution or a fat-tail distribution. I suspect that the near-constant level of violence in the past makes Pinker's position more believable that violence has in fact gone down. It's possible that large-scale conflicts will occasionally arise with enormous body counts, but the drop in violence on all lesser scales doesn't seem likely to be reversed, and that doesn't seem consistent with Taleb's models of financial system variability.

Overall, the book provides good news, and more fodder I can use to try to convince people that what appears in the news is exceptions rather than trends.

Sex at Dawn: Ryan and Jethá

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Chris Hibbert

Christopher Ryan and Cacilda Jethá's Sex at Dawn argues convincingly that monogamy isn't particularly natural for humans. It certainly is one common choice, but many modern people have a lot of trouble sticking to the program despite a lot of exhortation and systemic incentives promoting the practice. Ryan and Jethá marshall evidence from anthropology, evolutionary evidence, comparisons with other primates, and examinations of current practices. Their main argument is that a reasonable definition of "naturally monogamous" would mean that most people pair up with someone from the opposite sex, and aren't tempted to stray. There are a few species that mostly act that way, but looking at the broad range of what humans do, we're not like that. It's an interesting question as to why sociologists, and anthropologists seem to want us to believe that it is natural in the face of all the evidence.

There are several places in the book where the authors don't seem to really understand how evolution works. When talking about male parental investment, they ridicule the notion that maximum reproductive productivity is anyone's goal. It's clear from context that they're misunderstanding a discussion in which individuals are described as acting as if maximizing fecundity is the goal. But the evolutionary reasoning is just that those individuals who produce more offspring end up predominating in subsequent generations, regardless of why they acted that way. But regardless of this, they still make a strong case.

When biologists compare anatomy and mating behavior across species, human genitalia and sexual cycles don't make sense for a species in which couples stick together over the long term and don't cheat on one another. The size of male Genitalia, timing and (lack of) visibility of ovulation, breast prominence, are all unnecessary if the pair bond is unshakeable. They make sense when you assume each individual normally mates with multiple individuals of the opposite sex.

Our close relatives the chimpanzees and bonobos don't restrict themselves to single partners and we look more like humans evolved in an environment where individuals didn't restrict their attention to a single partner. In this kind of environment, evolutionary pressures push toward the large penises (by body weight), external scrotum, long duration of intercourse, and large volume of ejaculate you see in humans. If our ancestors had had reliable access to a partner, they wouldn't have needed these (evolutionarily) expensive features.

Another myth they take on is that of the demure female, uninterested in sex. It certainly occurs, but it's not predominant, either in societies (like ours) that constantly promote the idea or in societies that don't. Ryan and Jethá also make it clear that, evolutionarily speaking, homosexuality is nothing to be ashamed of. Our nearest relatives and many other species engage in the practice, though seldom exclusively. Mainstream society's insistance that each person can be categorized as either heterosexual or homosexual, is just not consistent with our behavior or the evolutionary or anthropological evidence.

Anyway, if you're not sqeamish about these topics, it's a fun, eye-opening read. Not likely to change anyone's behavior, but maybe some people will feel less constrained about their choices. It'll probably also provide grist for some arguments, but that's a fine thing, too.

Charles Mann: 1491

0.2 Chris Hibbert 1491

Charles Mann's 1491 is a very interesting read. The main point is that the natives to the Americas were a lot more numerous and a lot more advanced before the arrival of the European adventurers than anyone realized until recently. Whatever you learned in school vastly underestimates the accomplishments and the scale of their civilizations. There are a lot of details still to be worked out, but that much seems clear.

Mann is very good at taking the discoveries and recent analysis and making the possibilities clear: there is disagreement in many cases about how many people were here, how much contact there was between groups, when and how they died off, and just how sophisticated they were, but at the end there is so much evidence that there was large-scale engineering in so many places (the North American Midwest, the Amazon basin, the Andes and along South America's west coast, and Central America) that the conclusion stands above the minor disagreements.

More than anything, it's an enjoyable read. Even though Mann is heaping up evidence, he tells good stories of how the people must have lived and struggled. He seems to make it clear when he is speculating, when the experts are in agreement on the basics, and when he is reporting on aspects of the history that are still in dispute. The North American natives didn't write anything down, so he can't tell many stories about individuals, but the South Americans had a variety of writing systems, so he's able to report on political struggles that demonstrate the extent of the civilizations and gives some hints about how the internal wars may have contributed to their demise in the face of the conquistadors and their diseases.

In all these areas, there are constructions that were large enough, and that have endured well enough that they are still visible if you know what to look for. Until recently, anthropologists and archaeologists didn't realize they were there, and so hadn't studied them. In the Andes and the western plains, there are dikes and large scale water works that have only been identified as such in the last twenty years. In the Midwest, there are humongous mounds that are clearly artificial. New pyramids have been discovered in the Amazon in the last twenty years using LIDAR that can penetrate the tree cover.

The mounds are a fascinating chapter all to themselves. My favorite is the Cahokia mound. Cahokia, near present day Saint Louis, was the largest (maybe the only?) city north of the Rio Grande for 300 years starting about 1000 years ago. They built a series of mounds, of which Monks Mound is the most interesting.

Its core is a slab of clay about 900 feet long, 650 feet wide, and more than 20 fee tall. From an engineering standpoint, clay should never be selected as the bearing material for a big earthen monument. Clay readily absorbs water, expanding as it does. The American Bottom clay can increase in volume by a factor of eight. Drying, it shrinks back to its original dimensions. Over time the heaving will destroy whatever is built on top of it.

To minimize instability, the Cahokians kept the slab at a constant moisture level: wet but not too wet. Moistening the clay was easy—capillary action will draw up water from the floodplain, which has a high water table. The trick is to stop evaporation from drying out the top. In an impressive display of engineering savvy, the Cahokians encapsulated the slab, sealing it off from the air by wrapping it in thin, alternating layers of sand and clay. [...] The final result covered almost fifteen acres and was the largest earthen structure in the Western Hemisphere: though built out of unsuitable material in a floodplain, it has stood for a thousand years.

The time of arrival of the pre-columbian inhabitants is more contentious than I realized. I've been using the figure of 13000 years before the present as the time that the first wave came over the Bering Strait, and wiped out all the mega-fauna. It appears that there were probably two waves of immigration before that, and possibly more, though the timing is completely unclear. There are indications that early humans were here as early as 30,000 years ago, and that there was another wave around 20000 years ago based on genealogical evidence and tantalizing archaeology. Those people didn't leave many artifacts, so there is still plenty of disagreement.

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