Razib Khan of Gene Expression has put together a series of charts on changes in trust in the United States over the last 40 years. The trust data comes from the General Social Survey, and shows a slight decline in trust over this time.

Besides some interesting results, such as the level of trust in the media, what struck me was the strength of the link between trust and education or vocabulary scores.

This result is consistent with earlier findings that trust correlates with IQ, as I discussed in my recent post. While that post focussed on the implications of increased trust on a country’s institutions, these results show that a range of trust levels exist within a country under these same macro-level institutions.

One interpretation of this is that within a country, there is assortment by IQ and education levels, which can allow micro-level institutions in which trust is rewarded to develop. What that implies, of course, is that lower IQ groups face a micro-institutional framework in which people behave in a less trustworthy way.

One commenter to Khan’s post suggested that high IQ people are more able to judge whether someone is trustworthy. I tend to agree with Khan’s response – that one can be trusting in an environment where trustworthiness flourishes. I would suggest that in many situations, high-IQ people are as likely to get fleeced as other people, but fortunately high-IQ people tend to live in environments where this is unlikely.

Bryan Caplan has a simple recommendation. Have more kids. If you have one, have another. If you have two, consider three or four. As Caplan spells out in his book, Selfish Reasons to Have More Kids, children have higher private benefits than most people think. Research shows that parents can take it easy, as there is not much they can change about their children. He also argues that there are social benefits to a higher population, with more people leading to more ideas, which are the foundation of modern economic growth.

Caplan provides a fun, easy to read book that gives a great, swift overview of his case. This is the book I’ll be giving to parents, grandparents and friends who have heard me go on about twin studies and genetics. I particularly like it that Caplan gives some practicality to the swathes of findings about trait heritability. Caplan brings to life the arguments of the giants on whose shoulders he stands, particularly Judith Rich Harris and Julian Simon.

I felt that the largest shortcoming of the book was that it does not address the third factor affecting outcomes for the child – non-shared environment. While heritability explains some of the variation in a child’s traits and outcomes, and nurture generally explains close to nothing, Caplan does not explore the research into non-shared environment. Instead, he puts the variation down to free will:

So far, researchers have failed to explain why identical twins – not to mention ordinary siblings – are so different. Discrediting popular explanations is easy, but finding credible alternatives is not. Personally, I doubt that scientists will ever account for my sons’ differences, because I think their primary source is free will. Despite genes, despite family, despite everything, human beings always have choices – and when we can make different choices, we often do.

Caplan states that several of his friends call his belief in free will his “most absurd belief”. While I don’t know all of Caplan’s beliefs, for the moment I will agree with his friends. In Judith Rich Harris’s The Nurture Assumption: Why Children Turn Out the Way They Do, she explored what this non-shared environment might be. In her case, she argued for the effect of peers. What bothered me most with Caplan’s take on free will was not that he did not agree with Harris’s suggestion, but rather, his “it’s all too hard” approach. Unlike Caplan, I expect that over the next few years we will add even further to the explanations for how non-shared environment influences children.

When Caplan came to addressing potential reasons why family size has decreased over the last 60 years, I wanted to hear his arguments in more depth. Take Caplan’s take on Gary Becker’s argument that as women now earn more, they have to give up more income to have kids:

This explanation sounds good, but it’s not as smart as it seems. Women lose more income when they take time off, but they also have a lot more income to lose. They could have worked less, earned more, and had more kids. Since men’s wages rose, too, staying home with the kids is actually more affordable for married moms than ever. If that’s too retro, women could have responded to rising wages by working more, having more kids, and using their extra riches to hire extra help.

It sounds neat, but Caplan assumes that the income effect, which would tend to increase the number of children, dominates the substitution effect, which would tend to decrease the number. It is perfectly plausible for the substitution effect to dominate and women to decide to have fewer children, but Caplan does not address this. He might be right, but as there is no depth to his discussion, it is hard to judge the strength of his argument.

Caplan does point out that in the United States, fertility bottomed out in the 1970s. This occurred despite further increases in income and Caplan uses this as evidence against any income based hypothesis. But the people having children in the 1970s are different to the people having children now. For those women who chose to have no children in the 1970s and possibly responded most strongly to the income effect, they did not contribute to the gene pool and any heritable predisposition has disappeared with them. It is the children of larger families that are having children today. Second, the net fertility rate in the United States is substantially affected by recent immigrants.

Caplan’s preferred view on the decline in fertility is that we have gained a small amount of foresight, allowing us to see the negative effects of early childhood, but not gained enough foresight to note the benefits of children when they are older. There might be some truth to this, but I expect that the other factors that Caplan dismisses are also relevant.

One point where I disagree with Caplan is around his statement that men and women see eye to eye on the number of children they wish to have. Caplan considers that this puts to bed any arguments around women having increased bargaining power. While Caplan’s statistic is true in the most basic sense, the number of children that a man or woman want are a function of a number of things. The main one of these is who the other parent will be. If a woman is paired with the man of her dreams she is likely to want more children than if she is married to a guy who showed promise but has gone nowhere. While Caplan notes that condoms have been widely available since the end of World War II, the pill gave women extra power to decide who exactly the parent is. There is some interesting scope for sexual conflict here.

When it comes to policy prescriptions arising from his position, Caplan explicitly opposes natalist policies to increase birth rates. Caplan states:

After natalists finish lamenting low birthrates, they usually get on a soapbox and demand that the government “do something about it.” There are two big reasons why I refuse to join their chorus. First, while I agree that more kids make the world a better place, I oppose social engineering – especially for such a personal decision. When people are deciding how many children to have, government ought to mind its own business.

Instead, Caplan suggests that grandparents replicate the natalist incentives privately. Given this, it is interesting that Caplan drifts into supporting natalist tax credits in his recent Cato Unbound essay (as I have commented on here). I prefer his arguments for the use of private incentives from his book than his more recent encouragement of government action.

As I noted in yesterday’s post, Bryan Caplan has written the lead essay for this month’s Cato Unbound on The Politics of Family Size. Caplan argues that as there are strong benefits to increasing population, libertarians should support “libertarian policies” to increase population, educate and persuade people to have more children and while they are at it, have more children themselves.

Caplan suggests that people underestimate both the social and private benefits of having children. In the case of the private benefits, Caplan uses twin research (among other things) to build the case that as a parent’s contribution to the child is largely in the form of their genes, children require less work than people think. This is a major focus of his new book Selfish Reasons to Have New Kids, which I am currently reading. I find these arguments convincing, and I will address them in more detail when I review Caplan’s book next week (the review can be found here).

The social benefits referenced by Caplan rest in part on the work by Julian Simon. A larger population has benefits as more people leads to more ideas. Caplan writes:

Economists’ central discovery about economic growth is that new ideas are more important than labor or capital. The main reason we’re richer than we used to be is that we know more than we used to know. We know how one man can grow food for hundreds. We know how to build flying machines. We know how to build iPhones. Best of all: Once one person discovers a new idea, billions can cheaply adopt it.

Caplan also notes that we tend to seek areas of higher population. Despite the problems with congestion and crowds, people choose to live in cities – and in fact, more than half of the world’s population now does so.

In the first response to Caplan’s essay, Gregory Clark questions for how long increased population will continue to deliver net benefits. Clark notes that there is a balance between the costs and benefits of population growth:

Population growth always generates gains and losses. More population drives up the cost of limited resources: land, minerals, and fossil energy. But larger populations reduce production costs through scale economies. … There is thus a race between resource costs and scale economies as population grows.

I have some sympathy with Clark’s argument. We have had a 200 year period, in some parts of the world, where the benefits of population have outweighed the costs. As Clark points out, the costs of population are evident in the time after the Black Death in Europe, with the lower population delivering incomes that were not exceeded again until 100 years after the Industrial Revolution. Today, there are many parts of the world where population growth has resulted in problems. Jared Diamond’s discussion of Rwanda in Collapse comes to mind. Some parts of the world are still in an effective Malthusian trap.

Even for the developed world, I am reluctant to extrapolate such a small slice of history too far forward. Eventually, population could catch up with and possibly overtake economic growth, as those who have a heritable inclination to have more children do so. Having stated this, I agree with Caplan’s argument that in the short-term for developed countries such as the United States, if resources are priced appropriately, people would be better off with the increased range of ideas that comes with a larger population.

On the fiscal (government finance) side, Caplan argues that despite concerns about the weight of new people on government programs, new children have a large, positive fiscal externality. Citing work by Wolf and colleagues (which I am going to have to read in detail – published here), Caplan notes that each child born in the United States has a $217,000 positive externality (2009 dollars). After noting the significant fertility effect of a small baby bonus in Quebec, Caplan suggests that anyone who wants to improve the government’s fiscal health should support natalist tax credits to boost fertility (I have some doubts about the strength of these effects for reasons I will expound in a later post).

This is one point where I depart from Caplan. While a tax credit is clearly better than a subsidy, this type of social engineering by government makes me nervous, particularly where it seems to be based on a fiscal cost-benefit analysis. In Australia, the social engineering attempts of successive governments have resulted in a horrible mess of tax credits for childcare, women in the workforce and stay at home mothers. While Caplan’s argument might be clean, the actual implementation never is.

The claim of a positive fiscal externality is also interesting. Given that the United States government runs a large deficit, it would seem that government spends more than it receives. Wolf and colleagues achieve their result of a net positive fiscal benefit to children by excluding pure public goods – that is goods that are non-rivalrous. An extra child should theoretically result in no extra expenditure for these pure public goods. Defence is one example.

The problem with this argument, however, is that government does not work in this way. As most governments’ persistent deficits suggest, governments tend to spend all that they receive. On average, people are close to fiscally neutral or mildly negative. On that basis, an extra child is likely to be fiscally neutral or mildly negative once you consider how a government will actually act and spend the surplus generated during the child’s life. In that case, I suggest that Caplan is on stronger ground when he argues of the positive social benefits received by other people, in the form of the ideas, goods and services produced by that child, rather than the child’s lifetime fiscal contribution.

This month’s Cato Unbound is on The Politics of Family Size. The lead essay is by Bryan Caplan, who is on a mission to get people to have more kids.

Caplan frames his piece around Julian Simon’s argument that people are the ultimate resource and that increased population is a good thing. He suggests that decreasing fertility should be worrying for those who believe Simon’s argument and he makes a case for libertarian approaches to increasing population (I should note that as Caplan seems to be an optimist, this worry is probably not a case of foreseeing impending doom, but a suggestion that things could be even better).

I’ll comment on Caplan’s general argument in another post, but, the first thing that struck me about Caplan’s piece was that I cannot recall another example of Julian Simon being referenced in support of an argument suggesting that there is a problem (that is, beyond arguments that government intervention is a problem). Simon is a favourite source of those who suggest we don’t need to worry about environmental degradation or human living conditions and, as Simon has shown, human living conditions over the last 200 years have invariably trended up.

Despite the manner in which Simon is usually quoted, Simon’s position was not that we never need to worry. As the following quote in Scarcity or Abundance: A Debate of the Environment suggests, worry is one of the mechanisms that solves problems:

Let me correct a misapprehension. I have never said that we don’t need to worry about anything. We need to worry about everything, in the same sense that you had to worry whether you’d get here on time, whether there’ll be enough food in your kitchen for next week, and so on. The world needs the best effort of all of us. I’m saying that the result of all this worry – and of your constructive work, of your throwing your life into trying to do good things for the world and for other people – is that on balance you will create more than you will use in your lifetime, and you will leave the world a little better than before, on average. So, while we all need to worry, we can forecast that the result of all the worries will be that we will wind up better off than we are now.

I don’t preach complacency. And certainly in my own life I don’t think you’ll find complacency. We have to struggle like the dickens. But we’ll win, we’ll overcome.

Simon’s statement describes a situation similar to the operation of the efficient market hypothesis, which in the semi-strong form suggests that fundamental analysis is of no use as current market prices reflect all publicly available information. If everyone believed that was true, no-one would spend effort trying to earn excess returns, which is what causes prices to reflect the publicly available information. The hypothesis is more likely to be true if some people do not believe it. Similarly, Simon’s argument suggests that one of the reasons we do not need to worry is because we worry.

On that count, Caplan’s concern might sit comfortably with Simon’s view, and Simon might have worried about declining population growth. But as for what action Simon would recommend, I am not so sure.

Update: I found a second Simon quote that I was looking for when I initially wrote this post – from The Ultimate Resource 2:

Of course progress does not come about automatically. And my message certainly is not one of complacency, though anyone who predicts reduced scarcity of resources has always drawn that label. In this I agree with the doomsayers – that our world needs the best efforts of all humanity to improve our lot. I part company with them in that they expect us to come to a bad end despite the efforts we make, whereas I expect a continuation of successful efforts. And I believe that their message is self-fulfilling, because if you expect your efforts to fail because of inexorable natural limits, then you are likely to feel resigned, and therefore to literally resign. But if you recognize the possibility – in fact the probability – of success, you can tap large reservoirs of energy and enthusiasm.

Last week, the New York Times ran a profile of economist Robert Fogel in anticipation of the release of the book The Changing Body: Health, Nutrition, and Human Development in the Western World since 1700, of which Fogel is a co-author. During his career, Fogel and his colleagues have amassed a mound of evidence on the shape and size of the human body and how this has changed over the last few hundred years. I have not read much of Fogel’s work before, but the book looks like it is worth a look.

The key theme from Fogel’s data is that there have been significant gains in height and mass as countries develop. As the Times states:

To take just a few examples, the average adult man in 1850 in America stood about 5 feet 7 inches and weighed about 146 pounds; someone born then was expected to live until about 45. In the 1980s the typical man in his early 30s was about 5 feet 10 inches tall, weighed about 174 pounds and was likely to pass his 75th birthday.

Across the Atlantic, at the time of the French Revolution, a 30-something Frenchman weighed about 110 pounds, compared with 170 pounds now. And in Norway an average 22-year-old man was about 5 ½ inches taller at the end of the 20th century (5 feet 10.7 inches) than in the middle of the 18th century (5 feet 5.2 inches).

This rate of change over the last few hundred years is much higher than that of the previous millennia.

The Times talks of how “technology has sped human evolution”, although this is not evolution as biologists would call it. Fogel infers no change in underlying genotype. Rather, Fogel calls it “technophysio evolution”, and it provides one of the strongest illustrations of environmental effects on phenotype. Technophysio evolution includes changes due to the womb environment, so might be considered to include epigenetics.

Having said that, this is another area where we should not ignore evolution in the biological or genetic sense. As much of Fogel’s work details, Americans around the time of the civil war were surprisingly sick, and were often ill from a young age. While improvements in environment have been responsible for much (or most) of the improvement in health and increase in body stature, there would also have been strong selection pressures on people at this time. While I am not hugely familiar with the literature, I would expect that there would be some differences in fertility by stature (as John Hawks suggests here). Three hundred years is enough time for genetic changes to have occurred.

Genetic considerations are also relevant to some of the debates about the meaning of Fogel’s results. For example, the Times quotes Angus Deaton, who is sceptical about some of the conclusions on height, and in particular, he questions whether they should be attributed mainly to nutrition. Deaton states that:

We don’t really understand why African adults and children are so much taller than Indian adults and children, but it can’t be their income, because Indians are much richer.

Is this missing the obvious genetic explanation?

Having said that we should not ignore evolutionary factors, stature information is still a useful indicator of development. If height in a developing country is stagnant or decreasing, it is a solid signal that living conditions are not improving. But, if height differences between countries persist despite income increases, consideration of genetics might allow us to stop worrying that everyone is not the same height.

In response to my recent post on some statements by Garett Jones on immigration and IQ, Jones tweeted:

@jasonacollins If slightly-below-average member of high-IQ country moves to low-IQ country, both means can rise: A new export for China.

Typically, I was wearing my developed-country hat when I wrote the post, and was considering migration from a developing  to a developed country. While migrant flow is typically in that direction, I missed the important implications for adoption of an IQ-focussed policy by a developing country. As Jones indicates, attracting slightly below average-IQ immigrants from China could boost the mean IQ of many developing states, and following his argument on IQ and trust, improve the country’s institutions and economic outcomes.

Many countries have historically benefited from Chinese immigrants (developed and developing alike), but I doubt if there is any other policy proscription that could deliver greater benefit. As Jones points out in his research, a two standard deviation increase in a country’s average IQ score would lead to a prediction of a 700 per cent increase in average wages, while for an individual, a two standard deviation increase predicts a 30 per cent increase. There are large positive externalities from high-IQ immigrants.

As an end note (and what triggered me to write this post today), test results for Australian students indicate that Australia’s existing immigration framework, which for many migrants has a strong skilled component, is acting as a reasonably strong, but far from perfect, filter. From The Age:

STUDENTS from non-English-speaking backgrounds do better than their classmates in all areas of literacy and numeracy except reading, according to test results released yesterday.

The results of last year’s national literacy and numeracy tests show that students from homes where a language other than English is spoken have higher average scores in writing, spelling, grammar and punctuation and numeracy than students from exclusively English-speaking homes. However, students with English language backgrounds typically do better in reading.

It seems, however, that Australia is unique in achieving this:

The findings are consistent with international test results released in December, showing Australian students with immigrant backgrounds did better on average than those without an immigrant background. Australia was the only nation in which this was true.

Gary Becker’s 1976 article Altruism, Egoism and Genetic Fitness: Economics and Sociobiology is an article that I cite often. Becker’s closing paragraph has one of the earliest statements of the benefits of combining economics and sociobiology. He wrote:

I have argued that both economics and sociobiology would gain from combining the analytical techniques of economists with the techniques in population genetics, entomology, and other biological foundations of sociobiology. The preferences taken as given by economists and vaguely attributed to “human nature” or something similar – the emphasis on self-interest, altruism toward kin, social distinction, and other enduring aspects of preferences – may be largely explained by the selection over time of traits having greater genetic fitness and survival value.

Despite my regular references to the article, I have not spent much time dwelling on the article’s substance, an analysis of altruism as an extension of Becker’s “rotten-kid” theorem. At the recent conference Social Decision Making: Bridging Economics and Biology, Alan Grafen addressed Becker’s paper in his plenary presentation. This triggered me to revisit the paper.

Becker’s “rotten-kid” theorem, first laid out in a 1974 paper, works on the following premise. Suppose there is a parent who cares about the welfare of their children and will give them wealth and other gifts. Suppose further that one of the kids is rotten and he would like to harm his fellow siblings. Becker argued that if the parent redirected money to the hurt sibling when the rotten kid acted on his impulses, the rotten kid would have an incentive not to harm his siblings as it would cost him in the form of lost transfers from his parent. This induces to rotten child to act benevolently.

In his 1976 article, Becker extended this argument to general altruistic behaviour. Suppose there is a single altruist in a large group that cares about the welfare of all the members of the group. They are willing to transfer resources to other group members to increase their welfare. Becker argued that any egoist in the group would refrain from harming the altruist or others in the group to the extent that the harm would cut transfers to them from the altruist. This altruism exists through interaction, not kinship, so does not need the altruists or egoists to be related.

As well as analysing from the perspective of consumption, Becker examines the fitness of the altruist and egoist and shows that a similar result holds. The only added element that a consideration of fitness requires is that transfers may contribute to the fitness of the altruists and egoists at different rates.

Becker provides an example where there is a single egoist and altruist and the egoist could increase his income by $800 at the cost of $5,000 to the altruist. As the altruist cares about both his own and the egoists welfare, the net result of the egoist’s action is that the egoist will receive a lower transfer from the altruist and on net, will suffer a loss due to his egoism. As the egoist will not take the selfish action, the altruist’s altruism could be said to have saved him $5,000 in income.

This example, while providing a useful illustration, indicates the weakness in the model. The egoist will only be restrained to the extent that the transfer lost would be more than the gain from acting selfishly. If we reversed the above the numbers, the egoist would unequivocally take the action. The equation becomes even less tenable as a group becomes large. Suppose there is one altruist in a group of 10. The size of the transfer any egoist would receive from the altruist would be expected to be very small, and unlikely to be of a comparable size to any gain from cheating. This is particularly the case if the gain for the egoist approaches the size of the loss to the altruist (the technical term for these types of situation is a corner solution).

One of the interesting points Becker makes is the distinction between actual and simulated altruism. In his model, altruists are actual altruists because they care about the welfare or fitness of others. Egoists are simulated altruists because it is in their own personal interest to act altruistic, despite their egoist underpinnings. From an evolutionary point of view, I am not sure this distinction exists.

I should note, finally, that there is no shortage of other literature that addresses the “rotten-kid” theorem and this paper, and shows the restrictive assumptions that need to be applied to the model for it to work (such as by Bergstrom).

Following yesterday’s post on Ian Morris’s approach to biology in Why the West Rules – for Now, below are my thoughts on the some other elements of the book.

In general, I found the book to be an interesting and easy to read description of the history of the West and East, and I will probably use it as a reference for that in the future. I recommend the book for this. At times it felt like Morris was describing “one damned thing after another”, and I found that I was waiting for the theoretical tie-ins. When they did come, they seemed weak, as Morris frames his theoretical explanations with what might be described as slogans, somewhat in the style of Thomas Friedman.

So, to Morris’s main points. First, Morris provides his central line that:

[H]istory is made by lazy, greedy, frightened people (who rarely know what they’re doing) looking for easier, more profitable, and safer ways to do things.

Morris takes this to be a universal human characteristic (no argument from me there), although as I suggested yesterday, Morris does not address whether there are differences in the inherent characteristics of the people who seek to meet these goals.

On geography, Morris is of the “maps, not chaps” school of thought. In addition to supporting Jared Diamond’s geographic account for the origins of agriculture and why development is higher some parts of the world, Morris uses geography to explain why the West discovered the Americas first and obtained the associated bounty.

As Morris describes, the size of the Atlantic and Pacific, island positions and prevailing winds made it far more likely that someone from the West would bump into the Americas before someone from the East. I don’t find that controversial. However, this leaves unexplained why small ships and crews were pouring out of Europe, with various degrees of incompetence, while China had become quiet on this front. For example, Morris describes Columbus’s systematic search for someone to sponsor his voyage to China. Morris suggests that it was inevitable that someone would support Columbus, and there were plenty of other explorers willing to take similar risks.

Given the level of exploration by explorers from the West and the absence of explorers from China, if the advantages of geography were reversed, China probably would still not have discovered the Americas, unless Zheng He had discovered it during China’s ocean going days in the early 1400s. Someone from the West, possibly through accident or incompetence, eventually would have. Morris explicitly counters the argument that culture led to this lack of exploration by the Chinese, suggesting that people develop solutions to the problems they face, which in turn creates new problems and so on. Morris argues that China was not engaging in this process of exploration and technological innovation as it did not match the problems faced by it at the time.

I found this approach by Morris to be a state or whole of culture centred view. The question in my mind is what were the problems faced by the majority of individuals. Whether from the East or West, people in the 1400s (or most eras) would be trying to increase family income and well-being, innovate new ways to increase business profitability and so-on. Morris spent little time considering what problems individuals faced, and most of his time on the state, which I am not sure reveals the true motivations of most of the economic actors.

Following from this concept that people respond to the problems they face, Morris writes of the advantages of backwardness and how social development creates the very factors that undermine it. I would rephrase it slightly to state that the traits, skills and ideas that are most useful at a point will depend on the environment, but the concept provides a useful encapsulation why development is not linear and why there is no steady lead of the West over the East (although as I discussed yesterday, that does not mean that there are no long-term underlying factors to be considered). Morris describes a Red Queen type scenario, where each side needs to run to stay still and over time each will have different advantages.

This approach allows Morris to weave in a Malthusian thread to the story. He notes that people can be better off when disaster occurs in per capita sense, such as after the plague, but that this may be negative for social development . At many times in the book I wished his index of development (which consisted of energy usage – which dominated the results until after 1800, war-making, communications and the largest city size) was accompanied by an individual level measure of well-being. Apart from individual well-being being what economists tend to be interested in, it might also have given some shape to the specific problems faced by individuals at any point and their respective motivations.

Finally, Morris closes his book with some predictions about the future. With a framework that suggests there are advantages to backwardness, you can argue that China will pull ahead. But drawing on Ray Kurzweil’s vision of the singularity and the looming horsemen of the apocalypse, such as climate change, it might all go bad. At this point, the book degenerates a bit into some home-spun wisdom, but I do give credit to Morris for making his predictions with an underlying theme that it is inherently unpredictable.

Over the Easter break, I read Ian Morris’s Why the West Rules- for Now. Morris seeks to develop what might be called a “unified theory of history” that can shed light on why the West rules the world and not the East. He covers from the emergence of the first members of the genus homo in Africa, through the development of agriculture and the Industrial Revolution to modern times.

Morris looks at his question through the lens of biology, sociology and geography. In this post, I’ll focus on Morris’s treatment of the biological factors, as his conclusions on biology make it obsolete for his central claims. I’ll offer my thoughts on the rest of the book in another post later this week (which I should note are more positive than what I am have written below).

In Chapter 1, Morris describes the history of human development. Starting from the emergence of homo habilis in Africa, Morris walks the reader through the various migrations of early humans out of Africa and their spread across the globe, the discovery of “Peking man” and finally, the Out of Africa migration that occurred 60,000 to 70,000 years ago. For Morris, the final migration from Africa and the fact that this migration generally swept away humans from earlier migrations is the nail in the coffin for any biological theory of why there is a difference between East and West. He states that:

If modern humans replaced Neanderthals in the Western Old World and Homo erectus in the Eastern regions without interbreeding, racist theories tracing contemporary Western rule back to prehistoric biological differences must be wrong.

Morris then looks at some of the evidence for interbreeding. While DNA evidence shows some interbreeding with Neanderthals, the similar, low proportion of Neanderthal genome in modern Easterners and Westerners suggests that this could not be a reason for the difference. He concludes that:

Racist theories grounding Western rule in biology have no basis in fact. People, in large groups, are much the same wherever we find them, and we have all inherited the same restless, inventive minds from our African ancestors. Biology by itself cannot explain why the West rules.

I find it odd that Morris tackles this 1930s argument, which can now only be described as a straw man. Morris should have addressed the modern argument that biology matters, which tends to focus on evolution in the last 60,000 years – that is, since modern humans left Africa. Differing selection pressures in the last 60,000 years and in particular, since the dawn of agriculture, has shaped human traits. This was the argument that Morris needed to discuss before he could ignore biology as it relates to his question.

Further, Morris’s statement that while people are different, you take large groups of these people and the mean traits of the group will be similar, is a sound statistical concept, but to hold it relies on you drawing the groups from the same sample. If you consider that different groups of humans have faced differing selection pressures, then measuring the mean traits of each group won’t bridge the difference.

Some of Morris’s other references to biology were also unsatisfactory. Through the book, Morris uses an index of social development as a framework for discussing development. His index suggests that between (about) 541 and 1773, Eastern development was higher than that in the West. On this basis, he states that:

[I]f Westerners really were genetically superior to everyone else, the graphs of social development that fill Chapters 4–10 would look very different. After taking an early lead, the West would have stayed ahead.

A biological explanation requires nothing of the sort. Through the book, Morris talks of “the advantage of backwardness”. This refers to the idea that in a more backward area, the pressures faced by that population may give them incentive to develop solutions to their particular problems that may lead to that area becoming more developed. In some ways it is an evolutionary idea, with different ideas working better in different times and places and the successful ideas being shaped by the relevant environment. Sometimes harsher environments are better for developing these ideas.

We can apply this same concept to biological explanations. Whether one group’s biological traits lead to a higher state of development than another depends heavily on the environment the group is in. The shifts between violence, disorder and peace that Morris describes through the book would change whether a violent disposition, health, patience or intelligence were more beneficial traits for an individual to have. Based on this, it is possible to argue that there are biological factors relevant to development without requiring linear growth in development. Was it between 541 and 1773 that certain traits in the West, which were particularly conducive to economic growth and the reproductive success, spread (as Gregory Clark suggests was the case for England in his book A Farewell to Alms), leading Europe to an Industrial Revolution before the rest of the world? Unfortunately, Morris does not address this point.

Update: Part II of my review can be found here.

In my last post, I questioned whether a stranger sitting next to you on a train would be more similar to you than an ancestor from 10,000 years ago and suggested that this could be tested genetically.

A few issues arise in testing this. First, as I suggested in the last post, the particular ancestor we choose might affect the result. If an ancestor contributed through only a single ancestral line (of the approximately 10^120 lines), any similarity due to ancestry will be very low to negligible, unless that person is, say, a direct male-male ancestor and has contributed the Y-chromosome, much of which does not engage in recombination (that is, the crossover of genes between the chromosomes inherited from ones parents).

A bigger issue in my mind is convergent evolution. Given the selection pressures that agricultural populations have been under, it is likely that a number of shared phenotypic traits (that is, traits that are expressed in the person) have emerged, with these traits having different genetic origins. Take the ability to digest lactose in adulthood, which has separate origins in Europe and sub-Saharan Africa (and possibly other locations). While the genetic mutations that cause the traits are different, the phenotypic result is similar, which reflects the common selection pressure.

I expect that this is the case for many other traits. Distinct populations developed agriculture in a number of separate locations, which is likely to have resulted in some similar selection pressures in these locations (I won’t describe these events as independent developments of agriculture, as is sometimes done, as they aren’t independent). If the traits favoured by the adoption of agriculture are similar, despite being expressed by different genes or mutations, they would spread and increase similarity between populations in a way which may not be apparent in a genetic test.

Given this, as I did in my last post, I still question whether Seabright’s statement would be generally true. Further, if we could also capture similar traits expressed through different genes or mutations, we may be more similar to the modern stranger than the genetic test would suggest.