by bobcousins » Wed 02 Nov 2005, 09:45:09
$this->bbcode_second_pass_quote('lyrl', 'I') agree that's she's right in her basic thesis: within a single culture, where wealth is increasing average fertility rates will go up and where wealth is decreasing average fertility rates will go down.
But culture is a HUGE factor in fertility rates. As is access to modern family planning methods. Especially in third world countries (the ones with the problems with population growth), these two factors way outstrip the effect she's describing.
It is a complicated picture, but if the assumption is that people make a rational decision based on some direct or indirect assessment of 'wealth', then surely the calculation is more like :
n = I / C
where n is number of offspring
I is income available for childrearing
C is cost to raise one child.
This has the property that birthrate is proportional to income where the cost of childrearing is roughly constant (as in these western examples)
In the industrialised world, the cost of bringing up a child - education, health, playstations etc, is significantly higher than in non-industrialised countries. This might explain why despite higher incomes, richer nations have lower birth rates. In fact, if you can get useful work out of a child, then they could be seen as a net asset.