Apparently the foraging life is more mentally demanding than is the farming life. Brain size rose during the forager era, but fell during the farming era. During the industry era brain size is rising again, yet another way we are returning to forager ways with increasing wealth.
There is a gigantic driving force for smaller brains, the 1% or so maternal death that occurs in childbirth per pregnancy in the absence of medical C-section due to cephalopelvic disproportion.
I think what is being selected for is greater specialization in brain function, programmed in utero. A tribe needs experts in many different fields, not everyone with equal abilities in all fields. I think that maternal cephalopelvic disproportion has driven greater specialization of the human brain and that specialization has to occur in utero, when the major structures of the brain are being formed.
If this is correct, it explains why no one can find any "genes for intelligence". There aren't any. What is important for a successful tribe with successful genes is that it have multiple experts. The tribe with an expert tool maker, an expert rope weaver, an expert wood carver, an expert tracker, an expert wild-animal domesticator, where those experts can pool their expertise and teach the other non-experts how to make and use each of their expert-level products will do much better than a tribe where all its members have the same level of expertise and has no experts.
The “successful” genes that make the tribe “successful” and so are shared by the members of the tribe are the genes that create diversity in abilities. That diversity can't be genetic because it would then require genetic diversity to achieve phenotype diversity and a tribe consists mostly of related individuals. The successful genes must be those that create cognitive diversity without genetic diversity. They must get their “diversity” from somewhere, they must get it from coupling to the environment in utero at the level of noise via stochastic resonance and not from genetics.
This hypothesis explains the inability to find genes for intelligence, explains the Flynn effect, it explains why animal models are inappropriate (they didn't have hundreds of millennia of evolution driving diversity in cognitive abilities in limited brain sizes).
Yes, they are. They had to keep track of all the predators of the day, defenses, escape and evasion tactics. They had to remember all local fauna, what's edible, what's poison, what they are more likely to catch prey near. Remembering countless prey animals, their habits, behaviors, capture techniques, their relation to other predators and prey animals. How to deal with competing clans, their habits, ranges, possibly partial cooperation. Studies have shown that indigenous populations more readily grasp geometry and similar spatially oriented sciences than people from developed countries. Along those lines, people with no economic training score better in economics than those with PHDs. Go beyond a certain extent in education and you get too much into the theoretical and you can hand pick anything that sounds good in theory to support your views or biases. Indigenous people deal with reality every day and very little social conditioning. So when you relate to them a theory, they are more likely to call BS on something that isn't workable or logical. They are more accurate on many topics than the educated from developed countries.
Where's the evidence that forager bands who survived into the 20th Century are terribly intelligent? We have lots of ethnographic data on, say, Australian Aborigines or Bushmen. Most of it is depressing about their ability to adjust to the modern world. In particular, abstract thinking is uncommon among foragers.
That sounds just like the old "Pith Helmet" myth, that Europeans had to wear pith helmets when in the tropics because their big brains would overheat in the sun, while small brained natives were protected by their thick skulls.
Nothing I have said questioned or commented on your attitude toward religion broadly, just the connection between it (or its proscriptiveness) and brain size. That was the initial subject of Robin's post and your comment
It is general knowledge that predators have bigger brains than herbivores, because huntig moving animals requires more cognitive effort that "hunting" fixated grass; than, it is logical that foragers should have bigger brains than farmers.
"Combined with social brain theory, that our brains are big to deal with complex "ocial worlds, suggests farmer social worlds are less complex. Perhaps this is because stronger town social norms better discourage hypocritical norm evasion."
I don't care what you think about my attitude towards religion. To be honest, I have friends or at least know people of probably every religion on the planet (Buddhist, Hindu, Sikh, Muslim, most flavors of Christianity). I get along well with these people as they do with me. For these people, religion is a part of their self and cultural identity. It is a personal belief system for them. I respect these people and their worldviews.
I have no problem with those who believe in religion as a personal worldview or philosophy.
I have absolutely no patience or tolerance for those who make a political ideology out of it. Religion has no place in politics, period. Those who try to inject religion into political discourse utterly disgust me.
They may be "psychotic", but they are not known for low IQs. Robert Aumann is orthodox, and Eliezer Yudkowsky at least was raised that way. He looks like he has a pretty big noggin to me.
Haven't read Gould's book, but I heard he relied on Franz Boas regarding skulls. If you don't mind reading racist blogs, some coverage of the anthropologist R. L. Jantz' revisiting of Boas' work on skulls here.
Possible. However, people in both societies suffered from sub-optimal nutrition compared to their Western (or Southern) counterparts. So, parsing out which is due to sub-optimal nutrition as opposed to simply not using ones' mind is difficult in these two cases.
A very large driving force for brain shrinkage may be cephalopelvic disproportion. Without medical c-section, a few percent of women die in child birth because their baby's brain is too large.
Optimization of brain function, so that a smaller brain can do the same as a larger brain would be a fabulously successful adaptation.
Of course if thinking is of no value (or negative value), then a small brain would be better.
We are one species and of course foragers have exchanged genetically with farmers, however we would be one species regardless of whether these hunter gatherers had had genetic exchanges with farming communities or not.
In any case I believe the weight of evidence suggests that the cranial reduction in foragers is largely endogenous and not the result of gene flow from farmers. Certainly, the cranial size reduction trend in foragers predates the "last few thousand years".
There is a gigantic driving force for smaller brains, the 1% or so maternal death that occurs in childbirth per pregnancy in the absence of medical C-section due to cephalopelvic disproportion.
I think what is being selected for is greater specialization in brain function, programmed in utero. A tribe needs experts in many different fields, not everyone with equal abilities in all fields. I think that maternal cephalopelvic disproportion has driven greater specialization of the human brain and that specialization has to occur in utero, when the major structures of the brain are being formed.
If this is correct, it explains why no one can find any "genes for intelligence". There aren't any. What is important for a successful tribe with successful genes is that it have multiple experts. The tribe with an expert tool maker, an expert rope weaver, an expert wood carver, an expert tracker, an expert wild-animal domesticator, where those experts can pool their expertise and teach the other non-experts how to make and use each of their expert-level products will do much better than a tribe where all its members have the same level of expertise and has no experts.
The “successful” genes that make the tribe “successful” and so are shared by the members of the tribe are the genes that create diversity in abilities. That diversity can't be genetic because it would then require genetic diversity to achieve phenotype diversity and a tribe consists mostly of related individuals. The successful genes must be those that create cognitive diversity without genetic diversity. They must get their “diversity” from somewhere, they must get it from coupling to the environment in utero at the level of noise via stochastic resonance and not from genetics.
This hypothesis explains the inability to find genes for intelligence, explains the Flynn effect, it explains why animal models are inappropriate (they didn't have hundreds of millennia of evolution driving diversity in cognitive abilities in limited brain sizes).
Australian Aborigines are not as subject to predation as other indigenous cultures nor as diverse an ecosphere.
Yes, they are. They had to keep track of all the predators of the day, defenses, escape and evasion tactics. They had to remember all local fauna, what's edible, what's poison, what they are more likely to catch prey near. Remembering countless prey animals, their habits, behaviors, capture techniques, their relation to other predators and prey animals. How to deal with competing clans, their habits, ranges, possibly partial cooperation. Studies have shown that indigenous populations more readily grasp geometry and similar spatially oriented sciences than people from developed countries. Along those lines, people with no economic training score better in economics than those with PHDs. Go beyond a certain extent in education and you get too much into the theoretical and you can hand pick anything that sounds good in theory to support your views or biases. Indigenous people deal with reality every day and very little social conditioning. So when you relate to them a theory, they are more likely to call BS on something that isn't workable or logical. They are more accurate on many topics than the educated from developed countries.
Where's the evidence that forager bands who survived into the 20th Century are terribly intelligent? We have lots of ethnographic data on, say, Australian Aborigines or Bushmen. Most of it is depressing about their ability to adjust to the modern world. In particular, abstract thinking is uncommon among foragers.
That sounds just like the old "Pith Helmet" myth, that Europeans had to wear pith helmets when in the tropics because their big brains would overheat in the sun, while small brained natives were protected by their thick skulls.
Religious belief is a form of mental illness, plain and simple. Plenty of intelligent people are mentally ill.
Nothing I have said questioned or commented on your attitude toward religion broadly, just the connection between it (or its proscriptiveness) and brain size. That was the initial subject of Robin's post and your comment
It is general knowledge that predators have bigger brains than herbivores, because huntig moving animals requires more cognitive effort that "hunting" fixated grass; than, it is logical that foragers should have bigger brains than farmers.
"Combined with social brain theory, that our brains are big to deal with complex "ocial worlds, suggests farmer social worlds are less complex. Perhaps this is because stronger town social norms better discourage hypocritical norm evasion."
Or the social brain theory is simply wrong?
TGGP,
I don't care what you think about my attitude towards religion. To be honest, I have friends or at least know people of probably every religion on the planet (Buddhist, Hindu, Sikh, Muslim, most flavors of Christianity). I get along well with these people as they do with me. For these people, religion is a part of their self and cultural identity. It is a personal belief system for them. I respect these people and their worldviews.
I have no problem with those who believe in religion as a personal worldview or philosophy.
I have absolutely no patience or tolerance for those who make a political ideology out of it. Religion has no place in politics, period. Those who try to inject religion into political discourse utterly disgust me.
This is all I am going to say about religion.
They may be "psychotic", but they are not known for low IQs. Robert Aumann is orthodox, and Eliezer Yudkowsky at least was raised that way. He looks like he has a pretty big noggin to me.
Haven't read Gould's book, but I heard he relied on Franz Boas regarding skulls. If you don't mind reading racist blogs, some coverage of the anthropologist R. L. Jantz' revisiting of Boas' work on skulls here.
Yeah, the ultra orthodox are just as psychotic as the fundamentalist Muslims. Any form of religious fundamentalism is psychotic.
Possible. However, people in both societies suffered from sub-optimal nutrition compared to their Western (or Southern) counterparts. So, parsing out which is due to sub-optimal nutrition as opposed to simply not using ones' mind is difficult in these two cases.
A very large driving force for brain shrinkage may be cephalopelvic disproportion. Without medical c-section, a few percent of women die in child birth because their baby's brain is too large.
Optimization of brain function, so that a smaller brain can do the same as a larger brain would be a fabulously successful adaptation.
Of course if thinking is of no value (or negative value), then a small brain would be better.
We are one species and of course foragers have exchanged genetically with farmers, however we would be one species regardless of whether these hunter gatherers had had genetic exchanges with farming communities or not.
In any case I believe the weight of evidence suggests that the cranial reduction in foragers is largely endogenous and not the result of gene flow from farmers. Certainly, the cranial size reduction trend in foragers predates the "last few thousand years".
Foragers and farmers over the last few thousand years have high levels of interbreeding. We are one species, not two, and evolve together.