There's an evolutionary reason for that. Unlike less intelligent animals, humans can assess long term consequences for short term behavior. A cave man would lock up his daughter or keep an extra eye on his wife if he knew either were in heat. Because of that, women who had pronounced signs of heat bred much less than women who's heat was hidden. Nature has had to use trickery to get the human female pregnant, and has also given human females the reward of orgasm, something no other type of female animal has.
Before the invention of abortion and the pill, more than half the people born were accidents. The invention and widespread adoption of the pill happened too fast for nature to adapt new tricks. The result is having a profound impact on the gene pool. The smartest women do not have any kids, pretty much capping how smart women in general can be.
Odd. I'd say the smartest women DO have children. They understand the connection between genetics and the intelligence of offspring. They are not afraid of changing from a high-power career to a higher calling at home where they are raising the next generation. They understand the importance of replentishing the human race. They are, in a word, intelligent. Assuming that woman are so "intelligent" as to not have children is insulting, and ignorant.
I'm considered fairly smart. I have three children.
There are a LOT of female FReepers who will gladly disillusion you on that point.
On the point of heat, I'm of childbearing age still, and go into 'heat' once a month. It's just the normal ovulation cycle. Using your cavewoman/man analogy, most likely, women go into heat more often in order to keep their males interested, and AROUND. If he takes off, it's quicker and easier to catch another male to help raise the kids, because human children take the longest to grow into adulthood.
I'm sure that someone has already pointed out that if your first clause is true, your second clause must contain an error -- women bear all kids, at least until medical science gives is the Ronco Wonder Womb, so your cap is on the whole human race, not just women.
But your statement also contains an assumption that is actually a common error. Smart people don't always have equally smart kids. In fact, if they are smarter than average, the statistical tendency is for the kids to be less bright than they are, and closer to the median. But statistical tendency doesn't tell the whole story of the inherited part of intelligence. Because very smart people can have very dumb kids (more rarely than dumb people do, but it happens). And very dumb people can have much smarter kids.
Finally, IQ isn't entirely heritable. Scientists disagree on what percentage it is, from 50% or 60% to a high of 80%. (Yeah, there are scientists that say it is not heritable at all, but they are not people any psychometrician, or even any serious student of human biodiversity, would take seriously).
For lots of good info, analysis and just plain thinking on human differences, including male/female differences, check out Steve Sailer. If you're interested in how evolution has influenced humanity, Steve is a must-read guy.
d.o.l.
Criminal Number 18F
Somebody always has to bring up the evolution myth.
Huge BUMP!