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Human brain has reached it's evolutionary limit?

  1. Jul 1, 2011 #1
    I recently read an article in Scientific American,it was given that the laws of physics will prevent the human brain from becoming an even more powerful thinking machine,i would like to know how do the researchers predict about the human brain's evolutionary limit when we are one of the most recently evolved organisms.
    i also read about the inefficiencies in the brain caused due to it's size(elephant's).
    the brains of large mammals were compared to old hollow chested grandfather clocks and the brains of small flying insects were compared to exquisite pocket watches.
    Evolution has come across many problems before,why is it not possible for evolution to come up with more compact and efficient version of the human brain?,is it not possible for evolution to increase the density of the brain without increasing it's size by squeezing more neurons per unit volume?

    Modern generation of human beings are putting more pressure on their brains compared to their previous generations,we are trying to understand more complex phenomenon in nature and concepts in science and technology than our previous generations,scientific knowledge is expanding exponentially and we are trying to stuff all that into our brains to some extent atleast,does this not result in slight modifications in the human brain after some generations to increase the capacity?
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  3. Jul 1, 2011 #2

    Filip Larsen

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    I'll venture a guess: there are no particular advantages in being exceptionally intelligent relative to being normally intelligent in our current society that will lead to more off-spring, thus higher intelligence is not something genetic evolution can "optimize" any further. For it to have any effect you would need some evolutionary pressures to favoritize the "gifted", like giving them higher number of off-springs, better chances of survival, or something similar.

    However, if you include memetics [1] into evolution you can perhaps say that evolution in the memetic "dimension" still favors the intelligent and still has a lot of room left for "optimizing". Successful off-springs here are ideas and "visions" that are widely "used" or "assimilated" by the culture. Or in other words, on a culture level evolution is still increasing our capability for solving complex problems even if the individual human on a biological level should have stopped evolving in this regard.

    I'm no expert, but it seems to me that different levels of cultural capability for solving complex problems probably collaborate with the different types of human capabilities, thus what is required in human capability to solve a complex problem in year 2100 is probably different than it was in year 1900. For instance, in 2100 you may be more successful at solving complex problems if you have the ability to initiate and steer a huge computer based research program while in year 1900 you would have had to excel at highly abstract thinking (this is just example to illustrate my point - I obviously do not know what happens in year 2100). In year 2100 we may perceive people to be "highly intelligent" if they are able to solve complex problems even if they do it using different abilities than they would today.

    [1] http://en.wikipedia.org/wiki/Memetics
  4. Jul 2, 2011 #3
    Is this the article that you have been reading? If that is all there is to it, then I must say that I am skeptical. It does not provide any references to studies that support its claims.

    The brain can be made more efficient, but there has to be adequate selective pressure. And no, trying to remember more and process more information does not increase brain power. Evolution works by differential survival of organisms. See Natural Selection.

    The possibility of soft inheritance however still remains. But since I cannot find any studies regarding this, I am in no position to comment.

    I do not understand. The brain is to a meme what the environment is to a gene. How then can a meme favour intelligence? A meme cannot shape intelligence; in fact it is the other way round.
  5. Jul 3, 2011 #4

    Filip Larsen

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    In that section it probably didn't come across very well that I was talking about two kinds of intelligence: the biological one present in an individual human which evolves via genes, and the cultural one present in our society as a whole which evolves via memes.

    What I meant to say was, that cultural intelligence (and thus our capability to solve complex problems as a culture) may well increase through cultural evolution (memetics) even if it should be the case that biological evolution (genetics) no longer is "optimizing" biological intelligence, that is, even if it is the case that there no longer is any selective advantage in biological evolution for individuals having a very high biological intelligence.

    And I said this to offer a counter argument to the last paragraph made by the OP where he seems to pose the hypothesis that an increase in cultural intelligence (the ability for our culture as a whole to solve even more complex problems) can only be due to an increase in biological intelligence.
  6. Jul 3, 2011 #5


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    I agree with Mish on this one, there is nowhere near enough data to make a claim like that. It's not even sensible to make a claim that something has reached it's "evolutionary limit" as it implies evolution is has a goal to reach.

    I think you are kind of right here, our biology gives us our ultimate limits as individuals. No matter how good our nurture is at developing intelligence there are some thing's we just can't do.

    What is interesting is that group intelligence can grow just by adding more people who can specialise. This does have it's own problems though, interdisciplinary discoveries may be missed if the relevant collaborations don't occur but I would tentatively suggest that there is no limit to group intelligence providing the relevant number of trained people.
  7. Jul 4, 2011 #6
    Well yes that's simply the case of having sufficient processing power but insufficient data. One may have a super high-tech calculator but if one doesn't have knowledge of all the variables involved in the particular calculation one cannot solve the problem. The physical abilities of our brain haven't changed for the past few thousands of years and yet we are doing science that is immensely complex compared to those times. That is because we have more information and knowledge about the world than before.

    Socialization is yet another miracle of evolution I would say.
  8. Jul 5, 2011 #7
    It also doesn't take into account the silicon revolution, where in the future, it may be possible to meld neurons in the brain with perhaps virus sized computers to add to the size of available networks in the brain, making the whole thing much more intelligent.
  9. Jul 5, 2011 #8


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    And if any of that were to have basis outside of speculative fiction (sometimes espoused by scientists) it still wouldn't have anything to do with evolution which does not have anything to do with technological innovation save providing the platform for it and having the capacity to be affected by it.
    Last edited: Jul 5, 2011
  10. Jul 5, 2011 #9
    The cited article focuses on structure only and never mentions language and learning-theory based improvements.
  11. Jul 6, 2011 #10
    Well, if we consider that language skills and adaptive learning are direct influences in modern mating then you have a great point. Still, we know that high intelligence in parents does not necessarily translate to their offspring as much as physical traits do, so we'd have to have actual information over at least a couple dozen generations, with the ability to track the actual bloodlines to know whether a higher brain function were being passed on in the general sense. Those who choose to mate for beauty or strength would just make the overall experiment much harder to quantify. Then come issues regarding the parents like the order a 'gifted' child were born in versus age reached, and all the environmental factors that we impose on ourselves. I just don't think that we are anywhere close to being able to do anything more than lay a potential groundwork for this type of study.
  12. Jul 8, 2011 #11
    ok, i got it .The only reason why the human brain might have stopped evolving is because currently our society is not demanding the people to be exceptionally intelligent to successfully raise off-springs and not because evolution has reached it's limit.

    If in the future every person starts~~~``~```` demanding for exceptionally intelligent people as their partners then the human brain will get a chance to evolve into something even more powerful,but what about the laws of physics question?

    will the laws of physics come in the way of evolution and say "this is the end,there is no road ahead"?

    In the time scale of life on earth , i think evolution started focusing on developing intelligence only very recently,before that it was only about muscle power,speed or size,
    so i also agree that making such a statement that "the human brain reached it's evolutionary limit" is almost certainly wrong, as it is because of the current society that evolution must have slowed down(if it has in the first place) not because evolution is not capable of doing anything more.
  13. Jul 8, 2011 #12


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    Physics only applies in this situation to provide the basis for what is going to happen. If selective pressure on the brain increased (and by the way intelligence selection may not change the brain at all) then it could change in a myriad of ways. It's basically down to biology to see what is going to happen.

    As we don't have a comprehensive understanding of how ones genome affects ones intelligence (something the http://en.wikipedia.org/wiki/Connectome" [Broken] might help address) we can't explore this issue much further.
    Last edited by a moderator: May 5, 2017
  14. Jul 8, 2011 #13
    “Our brains have evolved to help our bodies find their way around the world on the scale at which those bodies operate. We never evolved to navigate the world of atoms. If we had, our brains probably would perceive rocks as full of empty space. Rocks feel hard and impenetrable to our hands because our hands can’t penetrate them. The reason they can’t penetrate them is unconnected with the sizes and separations of the particles that constitute matter. Instead, it has to do with the force fields that are associated with those widely spaced particles in ‘solid’ matter. It is useful for our brains to construct notions like solidity and impenetrability, because such notions help us to navigate our bodies through a world in which objects – which we call solid - cannot occupy the same space as each other.” Richard Dawkins (evolutionary biologist)
    Last edited: Jul 8, 2011
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