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On the contrary, the evolutionary argument here is that a few generations under these conditions would allow more biologically "stupider" humans to survive (sin

On the contrary, the evolutionary argument here is that a few generations under these conditions would allow more biologically "stupider" humans to survive (since intelligence isn't being selected for) and pass on their genes, creating future generations of dumber humans. Jared Diamond makes a similar argument in Guns, Germs, and Steel for why the people of New Guinea are smarter than their western counterparts.

JoeAltmaier 12y ago
Deny. There's no reason dying of wood smoke or disease selects for the smart or the dumb. Removing those pressures has no obvious effect on the intelligence of the survivors.
- JoeAltmaier 12y ago
  By that I mean, no evolutionary pressure on intelligence. Of course a healthy upbringing will increase exhibited intelligence.
Retric 12y ago
Human evolution is almost meaningless on those time scales.
- weeksie 12y ago
  There has been shrinkage in the average brain size over the last five thousand years. Intelligence is a very complicated thing and brain size might not be the only factor—that shrinkage might not even be relevant. But that does not mean that evolutionary change cannot take place on thousand year timelines.
  - Retric 12y ago
    Current theory is skull size was adapting based on temperature not intelligence. http://en.wikipedia.org/wiki/Brain_size#mediaviewer/File:Brain_Size_Map.png http://en.wikipedia.org/wiki/Brain_size#mediaviewer/File:Bra... Also, there are likely more people alive now with larger brain volumes vs five thousand years ago and the same apples to just about any trait you can name due to the rapid population boom. The important thing to note is the human population covers the globe. There are plenty of sifts in populations like Lactose tolerance becoming widespread over the last 7,500 years, but even that is a long way from becoming effectively universal.
    - weeksie 12y ago
      I think that was my point. You said that ten thousand years of civilization was too short for meaningful evolution. At least that was my understanding.
      - Retric 12y ago
        10,000 years is long enough for significant beneficial traits to spread widely. It's not enough time to Change neutral traits that used to be beneficial. That's generally a vary slow change consider most animals don't need dietary vitamin C even if there diets provide plenty of the stuff. However, you used the term "a few generations" as in below 1,000 years and that's rediculusly fast for a species that takes as long as we do to reproduce and have so few children.
        weeksie 12y ago
        I didn't use the term "a few generations", that was another commenter. :) That said, you mentioned a beneficial trait becoming neutral, and that's making the assumption that greater intelligence is neutral. It could be that larger social organizations reward slightly less intelligent critters. That would do the trick rather quickly. I'm not making that claim, but am saying that discussions around evolution and traits that we have bias toward seeing as "good" are fraught. There's also the further issue of intelligence being a very nebulous term that encompasses tons of cognitive traits, which makes any discussion of intelligence in evolutionary terms even more difficult. It's also possible that some of what we call intelligence is epigenetic.
        Retric 12y ago
        I don't think we have good data on people’s intelligence 10,000 years ago. But, civilization as we think of it only impacted a fairly small chunk of humanity for a relatively small time period. So, at best 'larger social organizations' was rather localized. Just 500 years ago lots of people in North America where living nomadic hunter gather lifestyles. Even just 100 years ago you could find tribes in many parts of the world still living hunter gather lifestyles little changed over the last 15,000+ years and probably similar to how people lived 100,000+ thousand years ago. As to epigenetic factors, the classic hunter gather lifestyle could be very healthy as long as population numbers stayed low. Farming actually lowered many heath indicators even as it allowed for massive increases in population sizes. PS: Anyway, evolution is only 'fast' when there are significant benefits or harms. If a single mutation or environment change increases survival chances by say +/- 1% it takes exponentially longer to spread than a +/- 10% change.

JoeAltmaier 12y ago

Deny. There's no reason dying of wood smoke or disease selects for the smart or the dumb. Removing those pressures has no obvious effect on the intelligence of the survivors.

JoeAltmaier 12y ago
By that I mean, no evolutionary pressure on intelligence. Of course a healthy upbringing will increase exhibited intelligence.

Retric 12y ago

Human evolution is almost meaningless on those time scales.

weeksie 12y ago
There has been shrinkage in the average brain size over the last five thousand years. Intelligence is a very complicated thing and brain size might not be the only factor—that shrinkage might not even be relevant. But that does not mean that evolutionary change cannot take place on thousand year timelines.
- Retric 12y ago
  Current theory is skull size was adapting based on temperature not intelligence. http://en.wikipedia.org/wiki/Brain_size#mediaviewer/File:Brain_Size_Map.png http://en.wikipedia.org/wiki/Brain_size#mediaviewer/File:Bra... Also, there are likely more people alive now with larger brain volumes vs five thousand years ago and the same apples to just about any trait you can name due to the rapid population boom. The important thing to note is the human population covers the globe. There are plenty of sifts in populations like Lactose tolerance becoming widespread over the last 7,500 years, but even that is a long way from becoming effectively universal.
  - weeksie 12y ago
    I think that was my point. You said that ten thousand years of civilization was too short for meaningful evolution. At least that was my understanding.
    - Retric 12y ago
      10,000 years is long enough for significant beneficial traits to spread widely. It's not enough time to Change neutral traits that used to be beneficial. That's generally a vary slow change consider most animals don't need dietary vitamin C even if there diets provide plenty of the stuff. However, you used the term "a few generations" as in below 1,000 years and that's rediculusly fast for a species that takes as long as we do to reproduce and have so few children.
      - weeksie 12y ago
        I didn't use the term "a few generations", that was another commenter. :) That said, you mentioned a beneficial trait becoming neutral, and that's making the assumption that greater intelligence is neutral. It could be that larger social organizations reward slightly less intelligent critters. That would do the trick rather quickly. I'm not making that claim, but am saying that discussions around evolution and traits that we have bias toward seeing as "good" are fraught. There's also the further issue of intelligence being a very nebulous term that encompasses tons of cognitive traits, which makes any discussion of intelligence in evolutionary terms even more difficult. It's also possible that some of what we call intelligence is epigenetic.
        Retric 12y ago
        I don't think we have good data on people’s intelligence 10,000 years ago. But, civilization as we think of it only impacted a fairly small chunk of humanity for a relatively small time period. So, at best 'larger social organizations' was rather localized. Just 500 years ago lots of people in North America where living nomadic hunter gather lifestyles. Even just 100 years ago you could find tribes in many parts of the world still living hunter gather lifestyles little changed over the last 15,000+ years and probably similar to how people lived 100,000+ thousand years ago. As to epigenetic factors, the classic hunter gather lifestyle could be very healthy as long as population numbers stayed low. Farming actually lowered many heath indicators even as it allowed for massive increases in population sizes. PS: Anyway, evolution is only 'fast' when there are significant benefits or harms. If a single mutation or environment change increases survival chances by say +/- 1% it takes exponentially longer to spread than a +/- 10% change.