In Search of Lost Time

Time is a fascinating concept. Today we learn that, according to the Oxford English Dictionary, ‘time’ is top noun in use terms in the English language. Interesting statistic that, especially as time is such an integral component in our decision making process.

Also in today’s news we learn from Dr. Kunio Kitamura of the Japan Family Planning Association that “”Japanese people simply aren’t having sex”.

Now why should these two little details be interesting, and what connection could there be between them?

Well, you guessed it, all this has got something to do with fertility, and one of the reasons why collectively we may be having less children. According to the Japan Times:

“An association survey of 936 people between the ages of 16 and 49 showed 31 percent had not had sex for more than a month “for no particular reason” — a condition known as ‘sexless.’ ”

And as Dr Kitamura tells us “As much as subsidies and welfare programmes are important, sexlessness is also a critical issue in this problem.”

Now I suppose to many of you this connection seems far fetched and ridiculous, but is it? Let’s think about all this a moment.

Only last week the Japanese Ministry of Health, Labour and Welfare proposed that workers who put in more than 40 hours of overtime a month will earn the right to an extra day off the next month. The reasoning behind this is that doing so much work is thought to leave Japan’s 30-something male with little time to think of other things – such as starting a family – remember that Japan’s birthrate, at only 1.25 per woman is still falling, is and is among the world’s lowest.

But why would having more time help. Well I have tried to address this problem briefly here. Basically their is an analytic framework called Life History Theory which comes to us from evolutionary biology and evolutionary anthropology, and life history theory is all about trade-offs, namely trade-offs between maintenance, growth and mating activity. Now clearly all this relates to our evolutionary past, but I cannot help feeling that the trade-off framework they have developed is also relevant to examine the way we take some strategic decisions, especially those related to time and energy allocations. Basically we could conceptualise what we do as allocating these resources precisely between maintenance-type, growth-type and mating-type activities. So on this account, Japanes males may be being thought of as giving too much to maintenance and growth (consumption, wealth accumulation) and too little to mating. Hence the concern of the Japanese government, and hence the low priority apparently allocated to sex.

Now I am not saying that this is any kind of explanation for low fertility, but it is interesting. And there is more.

Last year I posted here about global patterns in menarche age (age at first menstruation). What intrigued me at that point was the growing disconnect between the actual arrival of sexual reproductive capacity and the age of giving birth which has been steadily rising (I have subsequently discovered that these falling menarche ages may in some cases be more problematic than they seem since in their lowest-low age variety they are often associated with some form or other of fetal metabolic syndrome, whereby low birthweights – think mums who smoke, or practice dieting during pregnancy – are later asociated with early menarche, obesity and diabetes).

Now this disconnect may well have fertility consequences, and yes, it is all about sex. Basically the more the couple passes thirty the harder they have to try. And this may mean try and try and try, somthing which may not be so easy after a couple have been together ten years or more as it is between say five to ten years. (Some of the scientific reasoning behind this assertion can be found here).

Now to some extent it appears Japanese couples may be suffering from some of this ‘reproductive fatigue’.

According to a article in the March 2006 of the Japanese Journal of Population:

“Japan’s TFR in 2004 was 1.29 , which is “lowest-low” fertility, i.e. having a TFR of 1.3 or less.It seems to be impossible for cohorts born after 1960 to achieve the complete fertility of their predecessors. The delay in childbearing was accelerated again after 2000. It was shown that both nuptiality and marital fertility contributed to the recent fertility decline. For marital fertility, it was supposed that coital frequency and infecundity were primary factors, though data were not available.”

Well, as they say, data were not available, but obviously Dr.Kitamura is convinced, this is part of the picture. I will close with a quote from the Russian futurist painter Pavel Filonov, who when asked whether he was thinking of going to the front replied “As it is I’m waging a war already, but not for territory – for time. I am in a trench wrestling with the past for a shred of time”. Maybe there is a lesson here for some of these ‘sexless’ couples, go out in search of some of that illspent time, and get on with some wrestling!

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About Edward Hugh

Edward 'the bonobo is a Catalan economist of British extraction. After being born, brought-up and educated in the United Kingdom, Edward subsequently settled in Barcelona where he has now lived for over 15 years. As a consequence Edward considers himself to be "Catalan by adoption". He has also to some extent been "adopted by Catalonia", since throughout the current economic crisis he has been a constant voice on TV, radio and in the press arguing in favor of the need for some kind of internal devaluation if Spain wants to stay inside the Euro. By inclination he is a macro economist, but his obsession with trying to understand the economic impact of demographic changes has often taken him far from home, off and away from the more tranquil and placid pastures of the dismal science, into the bracken and thicket of demography, anthropology, biology, sociology and systems theory. All of which has lead him to ask himself whether Thomas Wolfe was not in fact right when he asserted that the fact of the matter is "you can never go home again".

22 thoughts on “In Search of Lost Time

  1. I have a copy of the British National Corpus on hand, so I can check if “time” really is the most common noun in English, But it takes an hour to scan with perl over a network connection, so it’ll be a while before I can confirm their result.

    As for sexlessness, there’s really no need to bring anything as remote a gaming evolutionary strategies into it. Long work hours and stress are characteristic of Japanese working life. Everyone old enough to know what long hours and stress feel like should be able to understand how that can kill your sex life. Binge drinking and smoking are also natural consequences of that kind of lifestyle, are well documented in Japan, and both are known to lower sexual response.

    A day off to compensate for 40 hours a month of overtime is like shaving 2 inches of snow off Greenland. The people who get that day off will: 1 – sleep. 2 – drink. 3 – watch a game on TV. 4 – Almost certainly not have the same day off as anyone willing to have a baby with them. 5 – Have a 10% chance – at best – of being fertile that day. 6 – Still question whether they have the time, money or household space to support offspring. Natalist bonuses that actually cover some significant part of the cost of having and supporting children, good paternal leave policies, and banning any level of overtime close to 40 hours a month might make a difference.

    Japan has the death penalty. Why not extend it to cover the manager of anyone working more than 40 hours a month of overtime? Give management a motivation to kick workers out and make them sleep with their wives.

  2. Scott,

    Really I don’t disagree with a great deal of what you have to say, although probably I draw the line at the death penalty under any circumstances :).

    Just two or three points:

    I am sure you are absolutely right that this kind of ‘pro-natal’ policy will have no impact at all. Primarily because it is a form of tokenism, and secondly even were it valid the kind of issues it is trying to address – like the decline in spontaneous passion among couples who have spent many years together before they start having children – are not the prime drivers of lower fertility, but rather secondary ‘aggravators’. The underlying issue is why people now wait so long before trying to have children. Here I am sure the key issues are growing gender equality and the arrival of the ‘knowledge economy’ which means that people spend more time in education and ‘learning on the job’ before they can become fully economically independent from their parents than they did in the old ‘industrial society’ era.

    The second thing is that I didn’t really mention game theory, nor did I intend to do so. No-one involved in LHT as far as I know is proposing that we have been evolved to think like this. I am simply saying that, as a matter of fact, it may be that this tripartite allocative trade-off framework offers a better description of how we actually take decisions that many of the other proposals which are on offer. In the first place I think it is much nearer to reality than the so-called homo-economicus model, and in the second it seems to me much more plausible than the old Maslow hierarchy of needs approach.

    This latter has long seemed to me to be flawed since many of the things which are identified as ‘higher level’ needs could really be thought to be among the most basic. Falling in love would be a case in point. It’s not really something we take decisons about, but it does involve a huge allocative switch of time and energy from maintenance to mating, at least in the short run. And of course, depending on who we fall in love with, this decision can either offer large long term growth benefits or entail huge long term costs, and all on the basis of very imperfect initial information.

    Thirdly, while I am talking about Japan, since this is where they seem to be discussing these issues at the present time, I am sure that all this has more more general applicability.

    Well, just a few thoughts.

  3. Oh, by the way, just look at the add in the left sidebar, “you didn’t want to do it anyway”. Rich in meaning that expression :).

  4. Well, I think that transaction cost economics has a lot to with “for no apparent reason.” As mating is moving from a more clan/hierarchically mediated act to a “market-like” activity, the transaction cost structure is bound to be different. In the case of modern relationships (in the west, in which I will include at least large parts of Japan post “lost in translation”) adaption costs within a relationship have moved forward in the relationship cycle and have become search costs. However, as the market size and alternatives have also grown significantly compared to the size of the village during the last demographic shift, unit serach costs per act of mating are likely to have risen and as such the timespan between two sexual acts. Combine that with Houellebecq, or the power law, as a not entirely implausible market outcome for short term relationships, and what you’ll get is, well, less sex than ever with more sex on tv than ever (well, you know, you’re in Spain ;)…

    Between choice dilemmas (Barry Schwarz, forgot the title of the book) rising unit search costs in a far less transparent mating market (now really a market structure), and rising economic insecurity, I’m not particularly surprised about people’s choices.

  5. God this is a stupid discussion.

    Until the Japanese government figures out a way to make more land, all the inducements in the world aren’t going to generate more babies. Japanese people, just like any other people, don’t want to spend their lives cooped up in some 600 sq ft apartment, packed into subways, squeezed around tiny tables in restaurants, and the only way they can change that is by having fewer children. For christs sake, put yourself in their shoes.

    The sooner the Japanese government (and its crowd of lunatic hangers-on around the world) accept this and come up with more sensible plans for dealing with an aging society, the better off they’ll be. This inanity about “sexlessness” is just one part of this denial. Exactly how much Japanese families find themselves in the position of wanting children but somehow not being able to muster up the energy to screw? And do we really expect that the 3 couples in Japan that fit this profile, with their miniscule free time and constant lack of energy, will make great parents?

    All this article tells us is that the same sort of neanderthal mentality that drives the US religious right exists in Japan; it just manifests itself in slightly different ways.

  6. “God this is a stupid discussion.”

    Well, I guess that is one point of view.

    “Exactly how much Japanese families find themselves in the position of wanting children but somehow not being able to muster up the energy to screw?”

    Well at least this is a recognition that at some level there is an energetics component here. Scott’s point about about stress is also valid at this point, especially in relation to cortisol levels in the female case.

    But the big point, Maynard, is that this isn’t only about Japan, it is already about what is happening across the whole developed world ex-US, and will soon be about China. There is no special shortage of land in China is there (or Russia for that matter). So I think special case pleadings don’t work here, an explanation on a more general level is needed. We still don’t have a satisfactory one.

    Tobias

    Very much to the point. I think the ‘factoring in’ process of relationship instability, or changing patterns of relationship, or whatever you want, is very important. This must affect how people structure their life cycle and life course decisions. Strangely, there has been relatively little work in macro-economc theory which takes account of this, although there has been, as you are suggesting, a micro-economic literature.

    Another neglected detail I’d throw in at this point is the consequence of growing gender equality in an environment of unequal parental ‘sunk costs’. Women still carry the major part of the burden here and so this must influence decision making about partners. The sociological and anthropological literature has looked into this somewhat, and essentially they have come up with the idea of increasing female ‘choosiness’. This choosiness, of course, only fuels the birth postponement process even more, which is just one more reason why I think the UN median forecast of a return to TFRs of around 1.9 is absolute pie in the sky (and of course all the economic projections are based on this). Again these issues do seem to be being discussed in Japan:

    http://news.bbc.co.uk/2/hi/asia-pacific/3694230.stm

    “and rising economic insecurity, I’m not particularly surprised about people’s choices.”

    The thing is Tobias are you talking about economic insecurity or employment insecurity here? They are not necessarily the same. In Spain for instance it is hard to talk about economic insecurity, what with the huge boom and everything, but qualified young people still do not find stable employment till they are in their late twenties. This is a sea change, and it is here to stay. It raises all the old issues about just how adaptationally ‘plastic’ we are in the face of rapidly changing environemnts. The jury is out.

    “UNBELIEVABLE”

    Hard to interpret this, since it could be a positive statement or a negative one :).

  7. Maybe Maynard is right, maybe this is the solution :).

    Extra-picky pandas given their space

    BEIJING (Reuters) – China is giving an unusually endangered species of panda extra space, privacy and protection to help the animals reproduce, state media said on Friday.

    he 300 pandas of a rare subspecies who call northwest China’s central Shaanxi province home will soon be protected by five new reserves in the fog-shrouded Qinling mountains, the China Daily said.

    “This will mean better protection for the animals and help enlarge their population,” Sun Chengqian, of the Shaanxi Provincial Forestry Department, told the newspaper.

    The reserves would cover about 80 percent of the pandas’ habitat once they are expanded from 181,100 to 500,000 hectares, the paper said.

  8. Unlike Maynard, I find arguments that people reduce their offspring because of physical crowding rather difficult to support. The birth rates are globally independent of crowding – they are high in some countries with very little space and low in some with plenty of space.

    Edward, I see what you mean about Life History Theory. It’s not evolutionary gaming. But I’m still sceptical about its utility in addressing declining birth rates.

    Fetal programming has been evoked to explain some important elements of embryo development lately, like how when you mate a big dog to a little dog, the fetus limits its growth to the size of the birth canal. It’s an interesting hypothesis for explaining the falling age of menarch in women. But I think the traditional explanation – better nutrition – still provides a better solution because there has been no corresponding drop in the age of first fertility for boys. Child-bearing consumes far more metabolic energy than sperm production, so making female fertility more dependent on resource availability than male fertility is plausible.

    Off hand, I’d have to question this:

    “For marital fertility, it was supposed that coital frequency and infecundity were primary factors, though data were not available.”

    Given the availability of birth control methods, I’d have to question if this is really a viable assumption. When my wife and I were younger and had decided we didn’t want children yet, we used birth control. There is also anecdotal data suggesting significant increases in real sexual frequency (as opposed to imagined) for people in their 30s in the developed world, motivated in part by the greater access to a stable partner while when you’re young, single and horny in your 20s, you may not just be able to just get laid when you want to.

    The overall rise in male infecundity is becoming a more serious issue as well. There is ambiguous data suggesting a sharp decline in sperm counts in the last generation in the developed world.

  9. Scott,

    I definitely think that at the bread and butter level we are not that far apart, of course, conceptually I am framing this in a very different way and I take complete responsibility for that. The ‘endogenous twist’ I am giving to LHT is entirely my own responsibility, although Kaplan really opens the door to this kind of interpretation (as to some extent does Carol Worthman).

    “But I’m still sceptical about its utility in addressing declining birth rates.”

    Well try this, which I completed last week:

    http://www.edwardhugh.net/Demogrpahic_Dividend_Additional__Mechanisms.pdf

    It’s more about health and longevity, but the core issues are the same, since at some level lonegvity and fertility are interconnected.

    Also I think you might be interested in the work of Carol Worthman:

    http://www.anthropology.emory.edu/CHB/members/worthman.html

    especially this one:

    http://webdrive.service.emory.edu/groups/research/lchb/PUBLICATIONS%20Worthman/PUBLICATIONS%20CMW%202005/Receding%20horizons%20of%20health.pdf

    She looks at endocrine mechanisms and is really working the stress-cortisol feedback loop.

    The thing is all of this is riddled with feedback mechanisms so it is hard to know where to start.

    “Fetal programming has been evoked to explain some important elements of embryo development lately,”

    This is very important, in fact in some ways it is the key (again see my paper I have linked to above)

    You may also find this paper by Barcelona paediatrician Lourdes Ibañez interesting in this context:

    http://pediatrics.aappublications.org/cgi/content/abstract/117/1/117

    “But I think the traditional explanation – better nutrition”

    The thing is there is not only ‘better’ nutrition, there is also ‘excessive’ nutrition, especially in the context of high carbohydrate diets and sedantism.

  10. The thing is there is not only ’better’ nutrition, there is also ’excessive’ nutrition, especially in the context of high carbohydrate diets and sedantism.

    Yes, the evidence linking obesity and early menarch seem pretty conclusive, although it’s impact on lifetime fertility is not something I’ve followed closely. The paper linking low prenatal growth to precocious puberty is interesting. I can’t read the article itself, and it probably doesn’t address the issue of causes, but it’s intriguing to think that fetal programming plays a role. It would support one of my favorite ideological axes to grind if true – undermining the role of genes in apparently inheritable outcomes.

    I like the Carol Worthman paper. “The social production of health” is a phrase to warm the heart of an old leftist.

    No, were not far apart on this really. This line of thought highlights a paradox in economic development that goes back at least to the 18th century: Greater social productivity should lead to actually better lives for people, but often it doesn’t. Productivity increases should lead to less stressed lives, but regularly don’t. I’m not sure who started making that point, but it predates the early socialists at least.

    Your paper raises another interesting point where there’s an existing literature that is probably not well known in economics or biology. You ask about the trade-off between brain growth and “improvements driven by greater interaction with the environment.” There is no discernible relationship between brain size within normal ranges and intelligence. This doesn’t make brain size irrelevant, but it strongly suggests that interaction with the environment is a far stronger factor in outcomes. The Vygotskyan school of social psychology is primarily about the kinds of mechanisms through which this might occur.

    I don’t have any trouble with your conclusion that there is strong prima facie evidence of health and life expectancy process operating at least partially endogenously in economic development. For an old leftist, this is a really easy conclusion to accept. But I still have an old reflex to recoil from giving biology – even developmental biology – too large a role in economic phenomena.

    As an example, I want to offer you a problematic argument based on the notion of health factors in economic development – one I heard years ago in Montreal when people started complaining about Haitian immigrants: In Haiti, there are quite serious health problems ranging from poor nutrition to widespread disease. Protein deficiency in particular is a problem, and protein deficiency is known to affect brain development. Ergo, Haiti is a mess because it’s full of intellectually inferior people and no endogenous economic or political solution to its problems is feasible.

    Now, I’m making this argument for the sake of devil’s advocacy – I do not actually agree with it – but I can see making such an argument within the framework you’ve outlined. Such an argument is quite damaging, and in Montreal in the 90s, it was at the root of a lot of nasty anti-Haitian racism masquerading as social realism. A framework that emphasizes the social origins of individual capital over the biological ones avoids this class of claim.

  11. Scott,

    “The paper linking low prenatal growth to precocious puberty is interesting. I can’t read the article itself, and it probably doesn’t address the issue of causes”

    Well you are not missing too much since the important info is in the abstract. Here is a post I did on her work:

    http://demoblography.blogspot.com/2006/06/lourdes-ibaez-menarche-and-low-birth.html

    Come to think about it you may find the other material on that blog (which isn’t really a blog at all but a links store) useful. The summary page for her work is in Catalan, but I guess you can hack that :).

    “undermining the role of genes in apparently inheritable outcomes.”

    I think this is more or less a done deal, maybe it will take another four or five years for this to get through to the general public, but the research is there and growing.

    This doesn’t mean that genes have no importance, some of us have longer noses than others, some have blue eyes, some have lactose resistance etc etc. But genes don’t have the importance they were assumed to have in explaining the big picture about health, IQ etc. This is what the modern epidemiological evidence tells us. We simply share far too many genes in common.

    “I like the Carol Worthman paper. “The social production of health” is a phrase to warm the heart of an old leftist.”

    She probably is an old leftist, but that doesn’t make her either right or wrong :).

    “This doesn’t make brain size irrelevant, but it strongly suggests that interaction with the environment is a far stronger factor in outcomes.”

    Of course, now think about the internet as an environment during the adolescent growth period, and think what might happen.

    “A framework that emphasizes the social origins of individual capital over the biological ones avoids this class of claim.”

    I’ll skip your Haiti point. Obviously there is plenty to do in a place like Haiti, but that is for another post. Except to say that obviously with a TFR at 4.7 the population pyramid is heavily weighted to the bottom end. The point about Fetal Programming is that it is both about the environment in-utero and during later growth, how these two interact, so the right kinds of intervention could make a difference, and relatively quickly.

    “A framework that emphasizes the social origins of individual capital over the biological ones avoids this class of claim.”

    Conceptually these two are now inextricably inter-linked. Social environments condition nutrition (which nowadays doesn’t mean mal-nutrition in the under-nutrition sense in the first world, but in the over-nutrition sense. The middle classes pay more attention to health education, and normally live longer etc.

    But these ‘poverty-trap’ ideational processes are horribly difficult to break down, that is the problem. Think smoking and pregnancy.

  12. All this health talk assumes that there is a substantial population around the world that wants to have more children and simply cannot. I see no evidence of this. I see inability to have wanted kids as a very minor yuppie ailment that occasionally is useful in the plot development of TV dramas and hence gets much more press than it warrants.

    How about, before we spend more energy worrying about whether the problem is too much meat or too many carbs or too little time or too much stress or global warming or cell phones, we get some evidence that this is the actual issue? I am not denying that most people round the world are having few kids. I have my own opinions as to why this is happening and that it’s a good thing. What I am not at all convinced of is that what is stopping them from having more kids is some kind of infertility (as opposed to the arguments I give, which I’m quite willing to see stated as economic arguments, ie “we’d love more kids but we can’t afford them”).

  13. TFR is around 1.9 if you correct for the increase in the age people get children so i don’t think the UN is so wrong though by guess is that this will only be happening after 2050

    ps. Edward, you made a type in your article. The Dutch hunger winter was 1944-45 and not in 43

  14. “ie “we’d love more kids but we can’t afford them”).”

    The thing is Maynard this doesn’t really ring true when you think about the fact that poorer people tend to have slightly more children. Are they better able to afford them? The poorest poor in the US start having children as teenagers.

    I think the problem is a little more complex than this. If people can’t afford them, it must be can’t afford them *and* do something else. That something else might be maintain a certain level of consumption (well above the poverty level) – in which case they are valuing maintenance and growth in purely materialist terms over mating and reproduction (which is their right, of course). Or it might be ‘I can’t afford to have the children I want now and continue to prepare myself for the long term career I want’, which means people partly postpone for economic reasons, and then find themselves running into all the fertility issues we are touching on as they try to have children ever later in life.

    Charly, thanks for the correction on the typo about the famine winter. On final achieved Tfr’s, the position is more complex as it varies from one country to another. Your figure of 1.9 is fine for Sweden, France, the UK etc, but hardly realistic for Germany, Spain, Italy etc. Also this argument fails to take into account the missing births produced by postponement, missing births which send a generational shadow across the age pyramid for anything from 30 to 50 years, depending on how long the postponement process actually lasts.

  15. The issue Charly raises is important but horribly technically complicated, since it involves sorting out and differentiating between ‘tempo’ and ‘quantum’ effects. For those who follow this, it is worth making the point that final ‘quantum’ data only becomes available as all the women in a particular cohort pass reproductive age. The evidence is that since 1960 quantum levels have been declining slowly but steadily across the developed world with each successive cohort that has passed the finishing line.

    The big issue is the US, and whether the US case is a statistical ‘blip’ cause by:

    i) Late initiation of the postponement process among the Afro Americans

    ii) the arrival of large numbers of Latinos with comparatively higher fertility (although they, of course, are now initiating postponement

    iii) Continuing high fertility among statistically insignificant populations in Idaho and Utah.

    Analytically the whole process can possibly best be understood using an LHT allocation trade-offs model originally developed by Lack (1954,which was well in advance of the more reduced economic version of this subsequently promoted by Becker) where there are *two* dimensions, quantity/quality and reproduce now/reproduce later, the former is essentially quantum, and the later essentially tempo.

    Some idea of the actual cohort situation in Japan can be derived from this lengthy extract I reproduce from the Japanese report linked-to in the main post:

    1-1. Cohort Fertility

    The Complete Fertility Rate (CFR) of a real cohort is a more desirable measure than the TFR, because the latter suffers from tempo distortion and the parity composition effect (Ortega and Kohler, 2002). The problem is that the CFR cannot be determined until the cohort completes its reproduction. However, the CFR of cohorts in their forties is predictable because only a small number of births will be added to the current level. Figure 1 displays the cumulative fertility relative to that of the 1950 cohort, using the scheme by Frejka and Calot (2001).

    Although the 1955 cohort was behind its predecessor in the early twenties, it succeeded in catch up and will fulfill a near replacement level. However, a significant decline in the CFR for cohorts born after 1960 seems to be inevitable. The cumulative fertility of the 1960 cohort is 1.84 at age 43 and will not reach 1.9 eventually. Though it is difficult to predict the CFR for cohorts born after 1965, the postponement in the early twenties seems too serious to be compensated later. Thus, the CFR of younger cohorts in Japan can be as low as 1.6, which is predicted for Italian cohorts (Frejka and Calot, 2001, p. 112; van Imhoff, 2001, p. 55).

  16. “The thing is Maynard this doesn’t really ring true when you think about the fact that poorer people tend to have slightly more children. Are they better able to afford them? The poorest poor in the US start having children as teenagers.
    I think the problem is a little more complex than this. If people can’t afford them, it must be can’t afford them *and* do something else. That something else might be maintain a certain level of consumption (well above the poverty level) – in which case they are valuing maintenance and growth in purely materialist terms over mating and reproduction (which is their right, of course). Or it might be ‘I can’t afford to have the children I want now and continue to prepare myself for the long term career I want’, which means people partly postpone for economic reasons, and then find themselves running into all the fertility issues we are touching on as they try to have children ever later in life.”

    Fine, the opportunity costs are higher for wealthier people. That’s one more way of stating it.
    You’re missing (or avoiding) my central point which is that I see no reason to believe that lower fertility is a consequence of something physical (or quasi-physical like being too tired) as opposed to being a choice.

  17. You’re missing (or avoiding) my central point which is that I see no reason to believe that lower fertility is a consequence of something physical (or quasi-physical like being too tired) as opposed to being a choice.

    But choice is based on preferences, and while sometimes preferences may seem arbitrary, the marketing industry would not exist if they were not informed by something.

    While the most direct relationship between tiredness and childlessness, we’d like children but we’re too tired to do the deed, does seem absurd, I’d readily believe that stress due to overwork can negatively color one’s estimation of the world in general and one’s own means in particular, and cause one to underestimate one’s means for childrearing. Childrearing is an entrepreneurial act, and depressed pessimists rarely start businesses.

  18. Great, Robert, you “readily believe it”, Meanwhile I don’t.
    That’s what I’m asking for — some evidence as opposed to “well my gut feeling tells me”.

  19. “You’re missing (or avoiding) my central point which is that I see no reason to believe that lower fertility is a consequence of something physical (or quasi-physical like being too tired) as opposed to being a choice.”

    Oh, this is the issue. You are talking about the fecundity point, rather than the fertility one, if making this distinction is helpful. Of course I am saying that this is not an either/or situation, the underlying process is socio economic, although it is rather to do with being richer than poorer, so the economic badly-off arguments don’t work in a crudely economic materialist form. We make choices, but constrained or contextualised ones, they do not come ex-nihilo.

    Basically we could call fertility how many children we want to (or try to) have and fecundity how many nature lets us have. Postponement is all about fertility decisions, but then we collide with nature, since fecundity goes down with age. This is where being tired comes in, since with lower fecundity you simply have to make more effort.

    This article from Ruth Mace about the fecundity impact of putting a tap in an Ethiopian village makes the point, I think:

    http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10%2E1371%2Fjournal%2Epmed%2E0030087

    And if you want examples coming from modern female atheletes that exercise and dieting can make you too ‘tired’ to have children, then try this from Peter Ellison, who is, perhaps, the expert on this topic:

    http://www.healthsystem.virginia.edu/internet/neuroscience/Education/Spring2005NESC720/Ellison.pdf

    Of course dieting and exercise are choices for athletes, whereas not going to fetch the water was hardly a ‘choice’ in the Ethiopian case.

  20. Of course, Maynard, if we are both agreed that underlying the movements in fertility lie human decisions, the next question is what drives those decisions, is there a structure to them, or are we happy with ad-hoc explanations for each separate case.

    I think it is possible to develop a general theory, in fact that’s what I’m into right now, but to find out what that theory might be you’re going to have to wait for another post (we have to keep readers somehow). Anyway, don’t worry, in this department at least it promises to be a long hot summer :).

  21. I agree to your concept of time as an integral component in our decision making, that’s why it’s said “a stitch in time saves nine”.

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