Must know this graph….

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This graph better be known to you.

22 Comments

  1. The labels on the axes are? 
     
    Y: Volume in CC? 
    X: Thousands of years BP?

  2. yes.

  3. Rumor has it that Neaderthals had more cranial capacity, and therefore larger brains, than we sapiens- sapiens types do. 
     
    This begs questions about determining the organ’s processing power by measures beyond volume, like, say, surface area?

  4. they might have been bigger in body mass.

  5. they might have been bigger in body mass 
     
    Why should bigger body mass need more brain? The control needs of hands/heart/etc. do not depend on size!

  6. not true. the relationship is not totally well characterized, but various hormonal, digestive and sensory-motor regulatory functions do require more neurons as they scale up in size. do a search in the symbolic species for the details….

  7. not true 
     
    Well, I know it’s not true. I just don’t understand why. To a small extent it makes sense to me, but not to the extent that we observe.

  8. humans are off the chart. but other mammals show a more modest covarying growth rate. also, there is a lowbound, mice have relatively large brain to body size ratios. a cheap explanation is allometric correlated response (ie; if you select for bigger body than development is constrained to give you a bigger cranium).

  9. How come cats are so clever and sheep so dim?

  10. In general carnivores are much more intelligent than herbivores. Before the development of agriculture (which permits people to obtain sufficient high quality protein from plant sources) most modern humans were essentially obligate carnivores. A different branch of hominids went the veggie route (the Paranthropus species), they developed bigger jaws and teeth but never developed a large brain. The natural status of modern humans in the EEA was to be carnivorous. Chasing after animals and devising projectiles and traps apparently selects for more g than gathering and consuming edible plants. If Lynn is correct about males having a few points of IQ advantage over females than this line of reasoning might be germane here as well (males as hunters, females as edible plant gatherers).

  11. My impression is that carnivory is highly regionally dependent. In some climates, a woman can easily gather enough calories for herself and children in a few hours per day.

  12. Cats aren’t very clever. 
     
    My guess is that wild herbivores are less dim than farmed animals, since the letter have been bred for docility. I’ve heard that the range of intelligence in dogs is very wide, with dogs bred for work very sharp, and dogs bred for appearance sometimes very dim.

  13. My guess is that wild herbivores are less dim than farmed animals, since the letter have been bred for docility. I’ve heard that the range of intelligence in dogs is very wide, with dogs bred for work very sharp, and dogs bred for appearance sometimes very dim. 
     
    all very correct from what i know. the nazi sympathizing ethologist konrad lorenz was worried that humans were becoming “domesticated” (ergo, dumber).  
     
    also, i think terming humans obligate carnivores is too strong a characterization. i think the extent depended on region, though it seems meat was always part of their diet from what i gather (midden).

  14. Michael Vassar says: 
     
     
    In some climates, a woman can easily gather enough calories for herself and children in a few hours per day. 
     
     
    And, to the extent that this is true, we should expect them to be less interested in paternal investment and more interested in other things, like indicators of good genes. 
     
    Wonder if we can get some such women into an MRI study to explore that …

  15. RichardSharpe said 
    “My impression is that carnivory is highly regionally dependent. In some climates, a woman can easily gather enough calories for herself and children in a few hours per day.” 
     
    I was talking about high quality protein, not mere calories. 
     
    Where exactly is this climate where abundant, and easily gathered wild plants provide sufficient high quality protein so that meat procurement by hunting males is not needed?

  16. Africa, as I recall. Steve Sailer has written quite a bit on this.

  17. Gorillas are vegetarians, and seem to get enough protein from mountain rainforests in Rwanda. 
     
    Now naming the protein-rich jungle plants they eat I can’t do, though I think certain beans and oil seeds fill this bill. 
     
    Harvesting any of these in a snowy winter was probably tricky, and best avoided in favor of mammoth hunting. 
     
    Go get ‘em Ogg…

  18. i think to the first approximation fryera’s contention stands. humans do need minimal supplements of protein and fats which are easiest to get via meat. gorillas are specialized vegetarians…the analogy with humans is weak. certain nuts might substitute for meats.

  19. “Cats aren’t very clever.” 
    What? Speaking as a close of observer of a great many cats, I could not begin to tell you stories that would blow that comment to smitereens. But there’s no arguing with a non-cat fancier. However, your comment was surprising because even those with no pro-cat bias have usually graded the cat about the same with the average dog.

  20. actually: “…blow that comment to smit[h]ereens.” but you get the idea

  21. “humans do need minimal supplements of protein and fats which are easiest to get via meat.” 
     
    Seems clear to me. 
     
    “gorillas are specialized vegetarians…the analogy with humans is weak. certain nuts might substitute for meats.” 
     
    Weak or otherwise, gorillas are large primates with similar biologies to humans and larger protein needs. If they don’t get their protein from animal sources, then they probably get it from plants.  
     
    Of course their willingness to eat most any plant they can, including thistles and tree bark, and spend most of their waking lives doing so, probably makes up in volume the quantity of protein needed from their relatively low-quality sources. But hey, I could be mistaken. 
     
    Doing this in a tropical rainforest with no real winter is one thing, and doing it in Siberia in January is another. Consuming meat, marrow and dairy products (eating animal foodstuffs produced from cellulose humans can’t digest) were very successful adaptations for us. 
     
    Pardon me while I leave to ‘put meat on the table’ by ‘making a killing’ and ‘bringing home the bacon’… ;-)

  22. “I was talking about high quality protein, not mere calories.” 
     
    I wonder if the high levels of iron and Vitamin B12 found in meat might be important as well.

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