4: Fertility
By Malthusian principles, the only way to improve living standards was to control the population to keep it in balance with the resources available to sustain it. That is, societies would either have to reduce fertility or increase mortality to prevent exceeding the sustaining capability of the resources of a given geographic area.
For a short while, having fewer of mouths to feed would increase the living standards of a population and/or increase life expectancy until their lack of productive capability brought resources back into balance with the population.
Likewise, an overabundance of population results in a decreased living standard, lower birth rates, shorter lifespan, which tend to persist until the overall population is decreased to the level that resources can sustain.
European Fertility
The author presents a table of data that show birth rates among women of varying ages in Europe before 1800 - there are subtle differences, but the range is generally between 7.6 (England) and 9.1 (Belgium and France) children per adult female (recall this is birth rate, and child mortality was high), with a breakdown of about 0.5 children between ages 20-24; 0.45 between 25-29; 0.4 between age 30-35, 0.3 between age 35 and 40; and 0.16 between 40 and 45.
The author considers various factors that influence these numbers: the absence of contraception, the morals and habits of the time, the typical age at which women were married, etc., and goes into more detail than is likely useful for most readers.
East Asian Fertility
The author suggests Malthus's assumptions about reproduction in eastern countries were not entirely accurate, and studies in recent decades have suggested that the birth rates in China and Japan were not significantly less than those in Europe, but the growth in their population is more attributable to lower child mortality rates, with the exception of intentional infanticide of female children.
AS such, the comparison finds that European women gave birth to 8.3 children on average, whereas in China and Japan, the numbers are 5.0 and 5.2 respectively. Likewise, birth rates among younger women were substantially less: 0.30 (compared to 0.45) for women aged 20-24, 0.25 (compared to 0.42) for women aged 25-30, etc. The author concedes "it is not known why fertility in East Asia was so low," but speculates it may have been a factor of low income rather than conscious control.
An additional factor driving down birth rates was the practice, particularly in China, of female infanticide, which not only reduced the number of children, but meant that almost 20% of men were unable to find brides and reproduce. It is speculated that female children were born, but their births were not recorded, and in such numbers that the actual birth rate in China might have been closer to the figure shown in Europe.
Forager Society Fertility
The author considers the fertility in forager societies, though it is difficult to compare given the shorter lifespan of individuals in foraging societies, along with a lack in documentation. The range varies from 8 children born to mothers between ages 20 and 42 in the Ache tribe, to a low of 3.8 between ages 18 and 26 for the Batak.
It's considered that forager societies are typically restrained in their reproduction, given fewer people living in proximity and the need of the female members of a tribe to contribute to the labor pool, and that lifespan are generally much shorter.
Explaining Preindustrial Fertility
Fertility was limited in almost all preindustrial societies, and with rare exceptions there is little evidence this was a conscious individual decision, nor was much control exercised at a community level. There is some speculation that personal choices, such as the age at which to marry and how many children to have, are guided by the degree of prosperity in a given society, which seems in line with the statistical correlation of these phenomena.
Given the lack of contraception, the author considers the age of marriage to be the primary means by which population was controlled, provided that it is coupled with a cultural imperative for unmarried women to practice abstinence.
The author also speaks to the "marriage market" in which people seeking spouses were a bit more particular: not any member of the opposite sex would suffice for a mate, but both parties would seem a mate who was similar or better to them in terms of their economic and social class, ethnicity, age, and other factors - not to mention the typical focus on finding a partner who is physically attractive and capable of providing for or supporting a household.
There is some mention of the church's attempt to intervene by refusing to marry couples, but there is ample evidence that there were alternatives: institutions such as Fleet Prison, Southwark Mint, and King's Bench were the 18th century equivalent of Las Vegas wedding chapels - and there is ample evidence that significant numbers of people travelled from nearby counties to be married when their local parishes refused to perform the rites.
The Birth Rate and Income
There's much debate over whether it is primarily the birth or death rate that changes to adjust population, and it's likely both have some degree of influence. Given that birth records do not provide the income or occupation of the parents, the author instead looks to the wills to determine the economic position of men and the number of heirs among whom their estate is divided.
What's suggested by these spotty numbers is that wealthier individuals had more heirs living at the time of their death than did poorer ones, which suggests a correlation between income and the number of children. Even so, this comes at the caveat that will as only created by those who had property to bequeath, though wills came into fashion for the lower classes.