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The human brain is getting smaller due to evolution

Magic Poriferan

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Let's step back for a moment. Perhaps the human race is not getting dumber. Even still, I severely doubt it is getting more intelligent. And perhaps this shrinking brain has nothing to do with our intelligence, in which case it's still entirely possible we are getting dumber.

Evolutionarily, I see no reason humans, as a species, would be development more individual intellgence. Our means of survival has become less and less individualistic essentially since we "began", and has accelerated in the direction as time has progressed. I repeat that the brain is expensive, and you don't keep what you don't need. So you might be right, maybe we're shedding the parts we don't need. Look at how things are going, those parts seem to be our capacity for solitary survival. We don't need those.

Any of the creatures on earth that have comperably populous masses, or acute division of labor (and there are few) are generally not regarded for their intelligence. Nearly all of them are hive insects. I suspect if every termite worker were a genius with an invidiualistic streak, it will hurt the species more than it would help. This approach was apparently more effective than other approaches, or else it would not have evolved. I simply can't fathom a reason humans would continue to develop all purpose intelligence at an individual level, given our current arrangement.

And as for our technology, that has little to do with cognitive skill, really. You could attribute most of it to written language. It was made possible only by our ability to preserve and send information. Now it appears that sets us apart from other animals, but I doubt it has improved much since we first developed it, and I doubt we suddenly had a click in our brains that granted us the ability to do it. I figure if, by some genie wish, you wiped the capacity for literacy from the human brain, we'd be neolithic people in one or two generations.
 

Stanton Moore

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This article explains a few things, specifically why brain size is not directly related to intelligence.

Bigger not necessarily better, when it comes to brains

"Animals with bigger brains are not necessarily more intelligent," according to Lars Chittka, Professor of Sensory and Behavioural Ecology at Queen Mary's Research Centre for Psychology and University of Cambridge colleague, Jeremy Niven. This begs the important question: what are they for?
Research repeatedly shows how insects are capable of some intelligent behaviours scientists previously thought was unique to larger animals. Honeybees, for example, can count, categorise similar objects like dogs or human faces, understand 'same' and 'different', and differentiate between shapes that are symmetrical and asymmetrical.
"We know that body size is the single best way to predict an animal's brain size," explains Chittka, writing in the journal Current Biology. "However, contrary to popular belief, we can't say that brain size predicts their capacity for intelligent behaviour."
 

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Whoever entertains the idea of such a radical collectivist path of evolution for mankind as being a favorable form of existence is my mortal philosophical enemy. I'm serious...
 

Magic Poriferan

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Whoever entertains the idea of such a radical collectivist path of evolution for mankind as being a favorable form of existence is my mortal philosophical enemy. I'm serious...

Let me be clear. I'm not talking about it being favorable in anyway that might phisosphically make sense to a human. Evolution doesn't care about what you think, though. There are animals all over this planet that live in ways that you or me might consider dreadful ways to live. They are here though, because that way ensured their survival.
 

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This article explains a few things, specifically why brain size is not directly related to intelligence.

Bigger not necessarily better, when it comes to brains

"Animals with bigger brains are not necessarily more intelligent," according to Lars Chittka, Professor of Sensory and Behavioural Ecology at Queen Mary's Research Centre for Psychology and University of Cambridge colleague, Jeremy Niven. This begs the important question: what are they for?
Research repeatedly shows how insects are capable of some intelligent behaviours scientists previously thought was unique to larger animals. Honeybees, for example, can count, categorise similar objects like dogs or human faces, understand 'same' and 'different', and differentiate between shapes that are symmetrical and asymmetrical.
"We know that body size is the single best way to predict an animal's brain size," explains Chittka, writing in the journal Current Biology. "However, contrary to popular belief, we can't say that brain size predicts their capacity for intelligent behaviour."

Agreed. Makes sense.

(Good thing I don't have a big head.)
 

ColonelGadaafi

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I doubt that we are experiencing a process of dumbing down. If the mean correlation between brain size and intelligence was high, then neanderthals would have been exceptionally intelligent, as they had approximately between 400-800 grams more brain mass then the average human who has between 1300-1400 kilograms of brain on average(100 grams less for women, since they have smaller statures), but they weren't, they were also shorter, and had a higher Brain to body ratio which is also traditionally correlated with intelligence in mammal species(having a larger brain means having a higher intelligence), but it was not the case. Neanderthals were stupid enough to not be able to adapt to the climate as our ancestors did, and drew the short strew in evolutionary competition, leading to their extinction. Also i think an explanation for the larger brain size of pre-historic homo sapiens, is that because of their protein based diet, it could've effect their average height, by making them taller, thus allowing them to have a greater muscular capacity which was necessary for things like hunting large prey, surviving and disease coping. And being larger, it is only reasonable to assume, that you're brain will correspond equally by being larger.

Infact i think that having a larger brain makes you dumber unless you have a higher neuron count on average, in which case a larger brain could be an advantage. Having a smaller brain means that the neuron density is higher, it also means that the neuroplasticity would accelerate at a faster rate.

I think rather then dumbing down, we are actually becoming more and more intelligent, as genotypes for intelligence are being more and more selected. Not just because of the accumulation of knowledge, but also because mental simulation, sufficient nutrition, education, market competitiveness is forcing the curve upward, in all of the world.

In fact modern day lifestyles with all of it's aspects, is far more demanding cognitively today in order to maintain then before. We have more writers, scientist's, philosophers, mathematicians, physicists then ever. While most of these might not be exceptional, they still excel enough to be adequate, which is by far speaks of how far the modern human being has gone. And no.. professions are not solely driven by being retaining information, we have far more complex machinations ongoing, like problem solving, comprehension, spatial perception, planning, reasoning, analysis, logic, which are all more or less a part of our daily lives, even if we have simple tasks as street sweepers or garbage collectors. Our societies are becoming more and more complex.
 

Fluffywolf

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Infact modern day lifestyles with all of it's aspects, is far more demanding cognitively today in order to maintain then before.

That raises a rather interesting question. This lifestyle and the beginning thereof is no more than several thousand years old. Surely not enough to evolve a brain. So from what need did the capacity to do what we do now come from in more prehistoric times? Hardships, climate changes, depleting food resources maybe? Stimulating our cognition in prehistoric times, the birth of the thinker race from the need to survive. A freaky byproduct of evolution. :D
 

ColonelGadaafi

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That raises a rather interesting question. This lifestyle and the beginning thereof is no more than several thousand years old. Surely not enough to evolve a brain. So from what need did the capacity to do what we do now come from in more prehistoric times? Hardships, climate changes, depleting food resources maybe? Stimulating our cognition in prehistoric times, the birth of the thinker race from the need to survive. A freaky byproduct of evolution. :D

It is recurring myth by social Darwinists that survival in prehistoric times demanded a lot of intelligence. The effect could only make as much as it's dynamism, it didn't take long for modern humans to perfect hunter-gatherer cultures, once the climates initially stabilized. In fact when you analyze the life of hunter-gatherers you will find that most of it was not that difficult.

From what we know of paleontology hunter-gatherers faced problems like:

1.Climatic change's.
2.Local predators.
3.Topography.
4.Opposing tribes.
5.Disease/Sickness.
6.Finding game-grounds and edible plants.
7.Securing a good basis.

None of this is particularly cognitively demanding, provided that you have ability to learn, some practical intelligence and perhaps a tad bit of innovation. While sure one must acknowledge the advantage of intelligence, which geared up smart humans to be able to more effectively deal with these challenges, i still don't think it had such significance that only the most intelligent of the species were able to survive. sure pre-historic survival does require a certain minimum of intelligence, but not to the point of it having drastic eugenic effects on the species as whole.

In fact every living human being is a descendant of human beings who managed to defeat all of these challenges, yet for the past thousands of years there has not been that much change in the average intelligence of mankind, which makes the "higher intelligence ensures survival" point moot.

Compare pre-historic survival to physics, and you'll find that the latter requires some of the most tedious intellectual conditioning and problem solving in order to comprehend even the most basic of concept's, on university level. So no.. i think the last 200 years has had monumental effects on the level of intelligence that we have retrieved. Humanity is as intelligent as ever, and as life gets more complex, and as we introduce more abstract concepts, humanity will have to to re adapt itself over and over again in order to suit the level of environment.
 
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Magic Poriferan

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I doubt that we are experiencing a process of dumbing down. If the mean correlation between brain size and intelligence was high, then neanderthals would have been exceptionally intelligent, as they had approximately between 400-800 grams more brain mass then the average human who has between 1300-1400 kilograms of brain on average(100 grams less for women, since they have smaller statures), but they weren't, they were also shorter, and had a higher Brain to body ratio which is also traditionally correlated with intelligence in mammal species(having a larger brain means having a higher intelligence), but it was not the case. Neanderthals were stupid enough to not be able to adapt to the climate as our ancestors did, and drew the short strew in evolutionary competition, leading to their extinction. Also i think the larger brains were caused by higher protein diet in our ancestors, thus giving them a larger mean height, which makes sense as height and brain size is correlated. The larger your body is, it is reasonable to assume that you're brain is proportionally larger.

Well, really, you and everyone else actually has incredibly little knowledge as to why the neanderthals died. They idea that they died simply because they were stupid is popular, but not exactly verified. And this kind of thing is coming from the same scientific community that tried to deny humans had neanderthal genes for as long as possible, but of course, they have finally been proven wrong.

.
In fact modern day lifestyles with all of it's aspects, is far more demanding cognitively today in order to maintain then before. We have more writers, scientist's, philosophers, mathematicians, physicists then ever. While most of these might not be exceptional, they still excel enough to be adequate, which is by far speaks of how far the modern human being has gone. And no.. professions are not solely driven by being retaining information, we have far more complex machinations ongoing, like problem solving, comprehension, spatial perception, planning, reasoning, analysis, logic, which are all more or less a part of our daily lives, even if we have simple tasks as street sweepers or garbage collector's. Our societies are becoming more and more complex.

And with society becoming more complex, the individual may become more simplistic and trivial. A cog in a machine.
 

compulsiverambler

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I think rather then dumbing down, we are actually becoming more and more intelligent, as genotypes for intelligence are being more and more selected. Not just because of the accumulation of knowledge, but also because mental simulation, sufficient nutrition, education, market competitiveness is forcing the curve upward, in all of the world.
They're not being selected for at all that I can see, at least not in developed countries. They're being selected against. The more intelligent you are the less likely you are to have children, and people with low intelligence don't die before giving birth significantly more often than anyone else. People with most mental disorders are dying young I would guess almost as often as they ever did, due to suicide, dangerous behaviour, self-neglect, homelessness, self-medication and addiction, but not people with just low or low-average intelligence. Most humans haven't benefited reproductively from being in the high-average range in any way I can think of for thousands of years.
 

ColonelGadaafi

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Well, really, you and everyone else actually has incredibly little knowledge as to why the neanderthals died. They idea that they died simply because they were stupid is popular, but not exactly verified. And this kind of thing is coming from the same scientific community that tried to deny humans had neanderthal genes for as long as possible, but of course, they have finally been proven wrong.
There is evidence which suggests that neanderthals were not as developed mentally in certain areas. For example

Neurological evidence for potential speech in neanderthalensis exists in the form of the hypoglossal canal. The canal of neanderthalensis is the same size or larger than in modern humans, which are significantly larger than the canal of australopithecines and modern chimpanzees. The canal carries the hypoglossal nerve, which controls the muscles of the tongue. This indicates that neanderthalensis had vocal capabilities similar to modern humans.[55] A research team from the University of California, Berkeley, led by David DeGusta, suggests that the size of the hypoglossal canal is not an indicator of speech. His team's research, which shows no correlation between canal size and speech potential, shows there are a number of extant non-human primates and fossilized australopithecines which have equal or larger hypoglossal canal.[56].



Steven Mithen (2006) proposes that the Neanderthals may have had an elaborate proto-linguistic system of communication which was more musical than modern human language, and which pre-dated the separation of language and music into two separate modes of cognition. He called this hypothetical lingual system 'hmmmmm' because it would be Holistic, manipulative, multi-modal, musical and mimetic.[59]

The separation of a Hmmmmm into the two systems of communication that we now refer to as language and music most likely occurred as part of the process by which modern H. sapiens originated in Africa. The appearance of compositional language would have had a profound cognitive impact, leading to the capacity for metaphor that underlies art, science and religion. Music has continued to deliver the adaptive benefits previously gained from the musicality of Hmmmmm, notably group bonding the expressing of emotional states, and the manipulation of behaviour by inducing emotional states in others.

which to me doesn't sound all too unreasonable, considering that they are a more primitive construct then homo sapiens, they pretty much died out before they could reach our point of development. While we on the other hand have proven that we can survive almost anything that nature throws at us. We have proven that we can make nature adapt to our needs instead of vice versa. Beginning with the neolithic and the invention of crops and animal husbandry.


And with society becoming more complex, the individual may become more simplistic and trivial. A cog in a machine.
You'd think so but the future presents endless possibility of outcomes. In fact i am guessing there is going to be a point where we will have progressed so far into technology that we can delve into the most complex problems today. In the future we will probably even be able to alter our own level of intelligence through artificial means( think of tinkering with neurological engineering). We could emulate or manipulate the processes that cause high intellect and accelerate these in humans. There is already literature on experiments with rodents, were scientist's implemented positive genotypes of "wisdom" genes into mice, which resulted in significant improvements in their overall performance in problem solving.
 
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kendoiwan

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This is false because evolution is only a theory and God doesn't do evolution, so there!
 

Amethyst

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Neanderthals had larger brains than humans...where did that get them?
 

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brain size doesent make real difference, the thing that makes the difference is how large that outer layer is when you straighten all the wrinkles(sorry i dont know what the fancy words are in english).
 

Andy

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There is a parallel for this, actually. Did you know that domestic dogs have brains that are around 10% smaller than wolves, relative to body mass?
 
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