Evolution of the Human Mind: Understanding Brain Development Over Time

[Graeme M]

I got to wondering about the development of the human brain, and the consequent development of human intelligence (and to an extent the mind). I googled the question and after reading several articles, was left not much the wiser in regard to the development of 'intelligence'. Part of my problem is not knowing what 'intelligence' is.

However, I think what I mean is that today's body of human knowledge is quite extensive. A smart well educated man today can know a lot of facts and can entertain rather sophisticated ideas about the nature of the external and internal environments. A scientist can know quantum theory, advanced cosmological concepts, deep knowledge about biology and microbiology, ever increasing understanding of the functions of the brain and mind itself.

This knowledge, this mode of thinking, is far in advance of the mind of a man of say 10,000 years ago. Yet how has the brain changed in that time to facilitate this?

My reading tells me that the size of the human brain increased over the course of several millions of years until around 10,000 years ago when brain size began to decrease slightly. Today's brain appears to be about the same size, or slightly smaller than, the brain of 10,000 years ago. Yet I found little to describe how the internal structures of the brain might have changed in that time.

Broadly speaking, I got the impression that the brain has not changed much other than size in the past 10,0000 years. The essential structures appear to have been well in place by that time.

Presumably then, the potential of a human brain to know and understand the knowledge that we have today was present 10,000 years ago. That raises some intriguing questions about the mind. But I suppose first I need to know if that core fact is true.

Has the human brain changed in the past 10-20,000 years? Or more exactly I guess, does science have a view on when the human brain developed its current form and function?

 

[Ryan_m_b]

The human brain hasn't changed in any significant way in tens of thousands of years. The reason why people can know so much more today is thanks to:

A) The accumulation of knowledge over thousands of years
B) A socioeconomic setup that allows for, and even encourages, long periods of education.

 

[Graeme M]

But this means that a modern human without the benefit of education or access to knowledge would be the same as a human of 10,000 years ago. It suggests that modern man's mind is essentially different due to the evolution of the mind itself. That is, accumulation of knowledge and long periods of education allow the human mind to form more complex associations and conceptual arrangements than it would otherwise be able to, regardless of the structure and function of the brain.

The brain, or mind, of any human in the past 10,000 years has the potential to be as knowledgeable, as smart as a modern human. Yet it was not because the mind itself had not 'evolved'? What does this say then for people of today from impoverished backgrounds? Would say a human from a tribal culture without access to either knowledge or education have a less sophisticated mind, less ability to form deep abstractions about his environment, than say a university professor from New York?

In effect, the accumulation of knowledge over time and the development of complex ideas and understandings can be informed to the modern brain by way of education and access (as you say), which further suggests that the mind of a person is more complex in earlier stages of life than in the past.

 

[Ryan_m_b]

But this means that a modern human without the benefit of education or access to knowledge would be the same as a human of 10,000 years ago.

Correct, likewise if you were to take a baby from 10,000 years ago and raise it in a modern setting it would be the same as anyone here. It's worth noting however that humans of tens of thousands of years ago might have known less but were by no means less intelligent. They were still remarkably capable of thriving in their environment, planning how to survive and building tools to aid them.

It suggests that modern man's mind is essentially different due to the evolution of the mind itself. That is, accumulation of knowledge and long periods of education allow the human mind to form more complex associations and conceptual arrangements than it would otherwise be able to, regardless of the structure and function of the brain.

Education can (but doesn't necessarily) make one more intelligent, in the sense that you practice logical and critical thinking. That has nothing to do with evolution.

The brain, or mind, of any human in the past 10,000 years has the potential to be as knowledgeable, as smart as a modern human. Yet it was not because the mind itself had not 'evolved'? What does this say then for people of today from impoverished backgrounds? Would say a human from a tribal culture without access to either knowledge or education have a less sophisticated mind, less ability to form deep abstractions about his environment, than say a university professor from New York?

No it's not because the brain has evolved significantly (I don't know what you mean by the mind evolving). People from impoverished backgrounds or primitive cultures are not necessarily less intelligent than a university professor. A professor has the benefit of education within their field and generally is quite intelligent but if you were to put them in the middle of a rainforest with no tools they would be in trouble. Conversely an individual raised in a tribe would be very knowledgeable on their environment but wouldn't know as much as the professor with regards to the professors field.

In effect, the accumulation of knowledge over time and the development of complex ideas and understandings can be informed to the modern brain by way of education and access (as you say), which further suggests that the mind of a person is more complex in earlier stages of life than in the past.

I don't know why you think it automatically makes the mind more complex. Why would an intelligent person's mind be more complex than another? What do you mean by complexity here? I'd argue that the ability to form complex thoughts is superficial compared to the entirely of a person's psychology.

 

[Choppy]

You might want to look into some anthropological studies of people who live in hunter gatherer tribes today (or at least in recent history). From what I've read there is no difference in intelligence between those and people who live in modern societies.

In fact if I recall there is an argument that modern lifestyles may actually make us less intelligent. Figuring out which icon to tap on you iPhone is a lot less complicated than figuring out how to build shelter with only a set of sharp rocks.

 

[Graeme M]

Yes I agree, I would need to read a lot more to gather a better understanding, but I think I can raise a few of my basic questions here and establish a starting point for understanding.

What I've gathered so far is that the brain was largely in its modern form over 10,000 years ago. However, the accumulation of knowledge over that time, and the capacity to retain and share that knowledge has helped modern humans to have a deeper understanding of the universe.

Apparently the capacity to learn and apply this greater knowledge existed in an individual from 10,000 years ago as much as in an individual today. The brain has not changed (evolved) in response to the more complex reasoning undertaken by individuals today.

So the mental ability of a smart person today is not a result of a physical change in the brain, nor has this ability driven any physical changes in the brain.

Now, the point that knowledge and capacity to apply knowledge is not intelligence escapes me a little here, but we can come back to that.

The question of evolution of mind is what I want to consider. If all humans had never chosen to pursue knowledge and its application beyond basic survival, such as for example a primitive tribe in the Amazon, humans would not have relativity, theories of the origin of the universe based on scientific observation, quantum physics and so on.

It seems to me that the way a mind works that permits these sorts of insights and mental frameworks requires an evolution of a sort. It requires the development of ideas over time, the retention of the learnings, and improved methods to apply these learnings. We codify this information into books and other records, but we still require that the mind be trained to be able to do so.

We do that from birth. Our educational institutions and our workplaces place demands on our minds but equally train our minds to be able to do this. That is why a native from the Amazon, or a 40 yer old woman from 10,000 years ago, could not undertake a discussion with a modern quantum physicist.

The modern physicist, or philosopher, or biologist, do far more intricate reasonings and maintain far more complex abstractions in their minds then did ancient man. Yet this is not due to a change in brain structure of function. And a pile of books of themselves do not confer that capability upon an ancient man. Or a modern Amazon indian. So 'something' has evolved over time. Is that simply knowledge? Or is it the mind (or more exactly, how a mind can be utilised)?

 

[Evo]

It seems to me that the way a mind works that permits these sorts of insights and mental frameworks requires an evolution of a sort. It requires the development of ideas over time, the retention of the learnings, and improved methods to apply these learnings. We codify this information into books and other records, but we still require that the mind be trained to be able to do so.

You are confusing the capabilities of the brain with information learned. Again, the brain has not "evolved/changed over the last ~10k years.

We do that from birth. Our educational institutions and our workplaces place demands on our minds but equally train our minds to be able to do this. That is why a native from the Amazon, or a 40 yer old woman from 10,000 years ago, could not undertake a discussion with a modern quantum physicist.

If you take the child of a Nobel prize winner in physics and place them in a tribe in the jungle to be raised as one of them, when they grew up, they, as you put it, "could not undertake a discussion with a modern quantum physicist". I fail to see what your point is. It has nothing to do with the brain, but with information that is learned. To be clear, we are talking about equally healthy, normal brains.

 

[Graeme M]

Yes I agree Evo. That is my whole point of interest. In thinking about how a human mind works, I began contemplating how it is that we think the things we do. It is clear that a man of 10,000 years ago simply could not have thought of a theory of relativity. So I wondered if the brain itself had changed over time to give rise to that capacity. Apparently it has not.

now I know little of human anatomy or development or even the history of man beyond a basic awareness of the timeline. So I was working with an incomplete idea of how all of this works.

So far, it is stated here that the brain has not changed. So the capacity to develop complex ideas and to form deep intellectual frameworks for inquiry evolved with no immediate application. It appears that somehow, the brain formed the ability to do this sort of thing without that sort of thing actually being done.

I think it is not reasonable to claim that a man of 10,000 years ago was as 'intelligent' as a man of today. But as I said, I'm not sure what intelligence is. To know what spear point to use is trivial, as is to know what food to eat or how to bind a stone axe. these are simply matters of survival.

The knowledge and application of knowledge today is far greater than the past. A smart man today is smarter, has more knoweledge, and can apply that better than a man of the past. our ideas in all things are far more developed - in science, in philosophy, in art, in music, policitcs, social and cultural frameworks, economics - you name it.

So something has evolved. It's not the brain. it's not 'knowledge', for what is knowledge without a mind capable of understanding it and applying it?

 

[Guco]

So something has evolved

Society has evolved. Our ability to pass on knowledge to the following generations. As people have said before you vastly overestimate the importance of factual knowledge (semantic memory) to everyday functioning. There is more to our brain than that.

To know what spear point to use is trivial, as is to know what food to eat or how to bind a stone axe.

Is it though? This reminds me of a quote about Paul Dirac (which I shamelessly copied from somewhere):
Another time, Dirac was watching Anya Kapitza knitting while he was talking physics with Peter Kapitza. A couple of hours after he left, Dirac rushed back, very excited. "You know, Anya," he said, "watching the way you were making this sweater I got interested in the topological aspect of the problem. I found that there is another way of doing it and that there are only two possible ways. One is the one you were using; another is like that. . . . " And he demonstrated the other way, using his long fingers. His newly discovered "other way," Anya informed him, is well known to women and is none other than "purling."

 

[Evo]

I think it is not reasonable to claim that a man of 10,000 years ago was as 'intelligent' as a man of today. But as I said, I'm not sure what intelligence is. To know what spear point to use is trivial, as is to know what food to eat or how to bind a stone axe. these are simply matters of survival.

The knowledge and application of knowledge today is far greater than the past. A smart man today is smarter, has more knoweledge, and can apply that better than a man of the past. our ideas in all things are far more developed - in science, in philosophy, in art, in music, policitcs, social and cultural frameworks, economics - you name it.

Do you think that someone just woke up one day and knew quantum physics? I believe this is where your thinking has gone wrong. We know what we know today because we have been learning bits and pieces for thousands of years and building on those bits and pieces. It's not the brain that has changed, it's the fact that we gain knowledge, then add to that knowledge, the amount of knowledge is increasing, and our brains are capable of handling that new knowledge without having to physically change, please stop using the word "evolve".

And if your ancestors hadn't learned to make that spear point or what food was safe to eat, you wouldn't be here right now, it was very important.

As Ryan pointed out at the beginning of this thread, you could take a child from 10,000 years ago, and raise them as a modern human and they would have the same potential to learn everything that a modern human can. They would not be sitting around making spears.

 

[Ryan_m_b]

If you think knowing how to make a spear tip is trivial of emplore you to go look up knapping and wood craft and try it yourself. Like many, many vocational skills it can take years to master.

 

[Guco]

Perhaps another way to think about this is that we can use several modes of thinking. I would argue that scientific reasoning does not so much rely on developing an advanced intelligence, but rather has more to do with learning how to suppress otherwise useful modes of thinking in favour of slow, deliberate and highly accurate reasoning.

Think about it like this: learning to speak is actually quite difficult when you think about it. Langauge is essentially a logical code, with many different rules and often allowing for ambiguous interpretation. Yet children are capable of learning it... simply by being exposed to speech. If you study language you realize the rules underlying it are actually not all that different from many other logical systems that we learn about in science. Speaking also requires advanced physical muscular coordination. It's just that because everybody does it that we don't perceive how amazing it is that every healthy human being can do it.

 

[Ygggdrasil]

One might argue that most of the advances in human knowledge that you speak about came not from biological changes but from cultural and social changes. The transition from nomadic hunter-gatherer societies to sedentary, agrarian societies during the Neolithic Revolution is thought to have been key to the development of technology-based and knowledge-based societies. In societies with agriculture (domesticated plants and animals) could produce food much more efficiently allowing them to support larger populations with a smaller fraction of the population dedicated to food production. This allowed for the specialization of labor, in particular, the ability for societies to support a number of non-food producing individuals who specialized in the generation and propagation of knowledge and technology. For example, before the invention of the printing press, much knowledge was preserved by monks who would work tirelessly all day making copies of books by hand. It is hard to imagine hunter-gatherer societies being able to support such activities.

Jared Diamond makes this point about the connection between agriculture and technological advancement in Guns, Germs and Steel when he points out that the most technologically advanced societies are those that arose in the geographic locations most amenable to the development of agriculture.

 

[Graeme M]

Thank you for some valuable comments. I think some have misunderstood where I am coming from. Also Evo, I think 'evolve' is exactly the right word. I use the word evolve in a broader sense. The idea is not limited to the concept of physical evolution of organisms. In the context I am using it here in respect to the mind, or to knowledge, I simply mean that something has changed, has become more complex, or more complete, over time.

Human knowledge is much richer, more complex and complete today than it was 10,000 years ago. I am not arguing that there is any intrinsic value to that, just observing the fact. Knowledge has 'evolved'. If you can think of a better word, I am happy to use it.

I also still argue that making a spear point, or any other skill enjoyed by stone age man, is a relatively trivial task IF our brains at that time were the same as those of today. I would imagine that most members of any stone age tribe would have been able to do most of the normal day to day tasks to which they applied themselves. And pretty much any normally functioning stone age man should have been able to accumulate and assimilate every last bit of knowledge of his culture.

Let me pose it another way. If a 40 year old man of today were transported to 10,000 years ago, could he have learned the various skills and knowledge of that culture? I would say yes because the skills and knowledge would have been very limited. 'Knowledge' would be simply the basics of survival plus perhaps some simple religious beliefs - our modern man would know far more than his ancient fellows. Manual skills are able to be learned, especially simple ones like tool making, hunting, etc. But could the 40 year old man of 10,000 years ago, transported to today, adequately learn enough to take his place as a smart man of today?

Let me ask another question that I should have asked earlier. What proof do we have that the brain of today is no different from that of the past? All I have been able to find is that we know the size of the brain by looking at fossil remains. And we can determine that generally speaking, the shape and surface of the ancient brain is not dissimilar to that of today. But what evidence do we have that internally the structures and function were the same?

 

[Ryan_m_b]

It's late here so I'm only going to comment on one of your points: evolve has a very specific meaning in biology and you are posting in a biology sub forum. Please refrain from trying to use it in a broader context as this will inevitably cause misunderstanding.

 

[Evo]

Thank you for some valuable comments. I think some have misunderstood where I am coming from. Also Evo, I think 'evolve' is exactly the right word. I use the word evolve in a broader sense. The idea is not limited to the concept of physical evolution of organisms. In the context I am using it here in respect to the mind, or to knowledge, I simply mean that something has changed, has become more complex, or more complete, over time.

Well, that's not correct, so please stop using it. You also don't seem to be willing to understand what everyone is telling you, so I am afraid that this thread is done. If you find an acceptable peer reviewed scientific paper that agrees with you, then you can start a new thread citing that source, but make sure that you read the rules and understand what is acceptable.

 

[Ygggdrasil]

Let me ask another question that I should have asked earlier. What proof do we have that the brain of today is no different from that of the past? All I have been able to find is that we know the size of the brain by looking at fossil remains. And we can determine that generally speaking, the shape and surface of the ancient brain is not dissimilar to that of today. But what evidence do we have that internally the structures and function were the same?

Anatomically modern humans first appeared ~ 200,000 years ago and began spreading throughout the world ~150,000-100,000 years ago. Thus, some of the research into changes in intelligence after this timepoint is controversial because it would have the implication that some populations of humans might be intrinsically more intelligent than others. In the absence of any anatomical evidence, we'd likely have to rely on molecular evidence (i.e. finding signs of recently acquired changes in our DNA) that would suggest changes to the brain. Unfortunately, figuring out how a change in DNA sequence translates to an effect on a complex trait like intelligence is a very difficult task, so while there are some ideas and hypotheses floating around, research has not been able to come to any firm conclusions.

Many studies have compared DNA sequences across different indigenous populations across the world to look for recent changes to the human genome (see this previous PF discussion), and have indeed found some changes. Many of the changes relate to immunity and probably arose in response to disease. There is also evidence in agrarian societies of adaptations to agriculture, such as the development of lactase persistence in many populations (our humans ancestors were lactose intolerant, and the ability to digest the milk sugar lactose into adulthood is a relatively recent evolutionary innovation).

There are some published reports that a few genes that could potential modify brain development have changed in recent human history. There are reports that certain variants for the genes for microcephalin and ASPM arose fairly recently (the authors estimate that the changes to ASPM arose as early as ~ 6,000 years ago), and show signatures of positive selection (indicating that the traits are beneficial). However, this research has been challenged as other methods of examining the data do not find signs of positive selection, and comparisons of people with and without the changes do not show any differences in cognitive abilities or brain size. Thus, it seems like these initial reports were false positives.

Other studies looking for recent changes in the human genome show no obvious signs that would suggest changes in brain development or brain function (though it is worth pointing out that we don't yet understand enough about genetics and neurobiology to confidently say we haven't missed anything), but there remains no molecular evidence that human brain function has changed in recent history. Because it is very difficult to prove a negative, on the basis of the fossil record and DNA evidence, we'll have to accept the null hypothesis that the brain today is no different from that of the past until we can find convincing evidence otherwise.

 

[Graeme M]

That's intriguing Ygggdrasil. Thanks for the links, I will have to read that and digest it. Some of what you say goes over my head, especially the molecular/genetic stuff. Not because I don't understand your words but I have little learning of that aspect of the subject.

However, you are saying (if I read you correctly) that a modern brain appeared around 200,000 years ago. Which is a long time ago. If I use 50,000 years ago as a point of reference, I would be safe to say that the brain of that time is generally understood to be the same as one of today?

The question of intelligence is tricky as I don't know what one defines as intelligence. From my rather ignorant perspective, I can observe dumb people and smart people. I assume we could say a dumb person is not as 'intelligent' as a smart person. But that is somewhat beside the point of my particular inquiry. I am more interested in the mind and its development and relationship to brain development, but I'll come to that in time if we can work towards that. But perhaps it isn't possible to separate 'mind' from 'intelligence'?

 

[Mark44]

I also still argue that making a spear point, or any other skill enjoyed by stone age man, is a relatively trivial task IF our brains at that time were the same as those of today.

I disagree. Have you ever made a spear point or stone knife or arrowhead? I can't say that I have, but then I am not saying that these are trivial tasks. They certainly wouldn't be trivial to someone who hasn't done them before. Even if you were able to make a reasonable facsimile of a spearpoint, you need to attach it to a pole it to a staff of some kind. How would you fasten the spearpoint to the staff? What kind of wood should you use for the staff? If you made an arrowhead, you still need to make the shafts to hold the arrowhead, and to fasten the arrowhead somehow? What would you use for the bow itself? For the bowstring?

I would imagine that most members of any stone age tribe would have been able to do most of the normal day to day tasks to which they applied themselves. And pretty much any normally functioning stone age man should have been able to accumulate and assimilate every last bit of knowledge of his culture.

Let me pose it another way. If a 40 year old man of today were transported to 10,000 years ago, could he have learned the various skills and knowledge of that culture? I would say yes because the skills and knowledge would have been very limited.

And I disagree here as well. The best metaphor I can think of for transporting someone to a time 10,000 years ago would be the situations people find themselves in following plane crashes or car accidents that occur in remote locations, or even hiking trips where the hikers get lost. Many of these people, even those without injuries, are unable to survive long enough to make their way back to civilization.

'Knowledge' would be simply the basics of survival plus perhaps some simple religious beliefs - our modern man would know far more than his ancient fellows. Manual skills are able to be learned, especially simple ones like tool making, hunting, etc.

"Simply the basics of survival..." and "simple [tasks] like tool making, hunting, etc."
I don't believe that any expert on survival skills would call such skills "simple."
Often the timetable for learning those skills is of very short duration -- if you can't figure out how to make a trap or snare or edged weapon fast enough, you might starve to death, or even be killed by a hungry cougar or bear. Survival skills that you wave off so cavalierly have to be learned over many years of practice.

But could the 40 year old man of 10,000 years ago, transported to today, adequately learn enough to take his place as a smart man of today?

I sincerely doubt it.

 

[Graeme M]

Mark, I am not sure if I can respond to your observations as I have been severely censured for differing with previous comments or offering my own opinions. I would observe that your comments appear to be your own opinions. I don't mean that in an antagonistic way, but do you have evidence to support your claims?

In saying what I did, I was not suggesting that making a spear point, or affixing it to a stick, is simple to someone who hasn't done it before. That would be a somewhat vacuous claim. Rather, I am suggesting - without evidence it is true - that the mental processes for making a spear are relatively simple by comparison to those required to design and build a jet engine. I think that to be able to design and build a jet engine requires the accumulation of a lot of knowledge and the application of particular modes of thinking/problem solving/conceptualisation that have been developed over many centuries.

I think that building a spear is relatively simple, and in context would have been easily taught to most members of a tribe. Designing and building a jet not so much. I venture therefore that a primitive man of 40 years of age brought to today's world would struggle to be taught many of the things that people of today can do. Whereas, a reasonably intelligent man of today transported to a time 10,000 years ago would be able to learn all of the necessary skills to survive, if he was supported in doing so. And he probably could learn all of the knowledge that the tribe possessed.

 

[PeterDonis]

the mental processes for making a spear are relatively simple by comparison to those required to design and build a jet engine

But one human being cannot design and build a jet engine all by himself; it requires many humans cooperating. Whereas one human being can make a spear by himself. So the extra complexity in the mental processes required is dealt with by increasing the number of humans involved, not by increasing the capacity of a single human.

to be able to design and build a jet engine requires the accumulation of a lot of knowledge and the application of particular modes of thinking/problem solving/conceptualisation that have been developed over many centuries.

So does making spears. The sophistication of spear points seen in archaeological finds is not constant; it improves over time. Humans still have to invent these things and then develop and improve the methods for making them.

And accumulating knowledge over many centuries is also a process that involves many humans, not just one. So, again, the increased knowledge (or better, the increased adaptability of the knowledge--see below) is a product of more and more humans being involved in the process, not any increase in the capacity of a single human.

I venture therefore that a primitive man of 40 years of age brought to today's world would struggle to be taught many of the things that people of today can do. Whereas, a reasonably intelligent man of today transported to a time 10,000 years ago would be able to learn all of the necessary skills to survive, if he was supported in doing so. And he probably could learn all of the knowledge that the tribe possessed.

I share Mark44's skepticism of these claims, but let's assume for the sake of argument that they're true. That still does not imply any difference in the mental capacity of a single human; all it implies is that the human of today has the advantage of having all the accumulated knowledge of 10,000 years taught to him from birth. That's not to say that the human who was born and raised 10,000 years ago didn't get a lot of knowledge taught to him from birth; it was just different knowledge, knowledge which, as we now know after 10,000 years of further exploration of knowledge, was far less adaptable to different situations than the knowledge humans are taught today. (Remember, this is assuming that your claim about today's humans being far more adaptable is actually true.) In other words, today's humans, by being taught the knowledge they are taught, are not taught a lot of knowledge that humans 10,000 years ago were taught; the total amount of "stuff taught" is the same, but the specific items taught are different, and that makes a big difference in adaptability.

 

[Ygggdrasil]

However, you are saying (if I read you correctly) that a modern brain appeared around 200,000 years ago. Which is a long time ago. If I use 50,000 years ago as a point of reference, I would be safe to say that the brain of that time is generally understood to be the same as one of today?

Yes. There is no evidence that the brain has evolved recently and existing evidence points to there being no major changes.

The question of intelligence is tricky as I don't know what one defines as intelligence. From my rather ignorant perspective, I can observe dumb people and smart people. I assume we could say a dumb person is not as 'intelligent' as a smart person. But that is somewhat beside the point of my particular inquiry. I am more interested in the mind and its development and relationship to brain development, but I'll come to that in time if we can work towards that. But perhaps it isn't possible to separate 'mind' from 'intelligence'?

I agree. Given the difficulties in quantifying intelligence, it's probably best to focus on brain development and morphology. The fact that diverse human populations that diverged earlier than 50,000 years ago share the same brain development and morphology suggests that no major changes have occurred during this period.

 

[Mark44]

Mark, I am not sure if I can respond to your observations as I have been severely censured for differing with previous comments or offering my own opinions. I would observe that your comments appear to be your own opinions. I don't mean that in an antagonistic way, but do you have evidence to support your claims?

Mostly anecdotal, and drawn from reports going back many years about people in survival situtations. I spend a significant amount of recreational time in places that most people would consider extremely remote, carrying everything I need on my back. Because I spend so much time in these remote areas, I'm more tuned in than most about the accidents that befall others in similar places, many of whom wind up dying, due to lack of knowledge about the environment they find themselves in.

In saying what I did, I was not suggesting that making a spear point, or affixing it to a stick, is simple to someone who hasn't done it before. That would be a somewhat vacuous claim. Rather, I am suggesting - without evidence it is true - that the mental processes for making a spear are relatively simple by comparison to those required to design and build a jet engine. I think that to be able to design and build a jet engine requires the accumulation of a lot of knowledge and the application of particular modes of thinking/problem solving/conceptualisation that have been developed over many centuries.

Sure, designing and building a jet engine, or for that matter, something as simple as a personal computer, takes a lot of expertise from a lot of people.

I think that building a spear is relatively simple, and in context would have been easily taught to most members of a tribe. Designing and building a jet not so much. I venture therefore that a primitive man of 40 years of age brought to today's world would struggle to be taught many of the things that people of today can do. Whereas, a reasonably intelligent man of today transported to a time 10,000 years ago would be able to learn all of the necessary skills to survive, if he was supported in doing so. And he probably could learn all of the knowledge that the tribe possessed.

IMO, the "fish out of water" business goes both ways. Of course, we can't transport anyone 10,000 years back in time, or from that time to the present, but a documentary I saw about 15 years ago might be instructive. It was long enough ago that I don't remember a lot of the details, but it involved a tribe of Indians in South America, possibly Venezuela. Three of the men (and it will be pretty much exclusively the men who hunt) went out hunting for howler monkeys, using very small bows and very long, poison-tipped arrows. They didn't find any monkeys, but settled for catching about a dozen tarantulas, each of which they wrapped in a leaf tied with a short piece of vine, keeping the spiders alive.

When the hunters camped for the night, they built a fire. They dispatched each tarantula, twisted off the head and abdomen, and threw the thorax/legs on the coals of the fire to singe off the hairs. The skills involved here, ranging from building a fire (no matches), to knowing enough about plants to know which were edible and which were poisonous, knowing how to hunt, and on and on, might be simple skills in comparison to creating a jet engine, but they are skills that IMO most of us don't have. If we survived long enough to acquire these skills, it would take years of study to do so. The hypothetical tribe of 10,000 years ago might not have the patience to teach a modern man the skills needed for survival, especially since so much of their time would be devoted to scratching out a living for just themselves. As evidence of this, consider that the Aleuts and Eskimos of not too many years ago set aged members of their tribe out on the ice -- making a living was too precariouos to justify continuing to feed the old ones.

The same documentary I saw also followed some members of the S. American tribe who had emigrated to New York. Although they were able to make a living in what for us would be a very hostile jungle environment, they were completely at sea in a modern city. I believe that plucking an ordinary individual out of his/her normal environment, whether a modern human going back 10,000 years, or someone from that time brought to the present, would have a very difficult time of surviving.

 

[scientific601]

Just to add some varying opinion that states that it's possible that knowledge is inherited. That would support the view that the physical structure of the brain does "evolve" based on experience / learning.
http://www.extremetech.com/extreme/...fears-and-memories-can-be-inherited-via-sperm
http://phenomena.nationalgeographic...nherit-specific-memories-because-epigenetics/

 

[Evo]

Just to add some varying opinion that states that it's possible that knowledge is inherited. That would support the view that the physical structure of the brain does "evolve" based on experience / learning.
http://www.extremetech.com/extreme/...fears-and-memories-can-be-inherited-via-sperm
http://phenomena.nationalgeographic...nherit-specific-memories-because-epigenetics/

None of this suggests a physical change of the structure of the brain, which is what the OP is suggesting, and it's not what we consider "evolution". The brain is capable of learning new things without the brain having to physically change.

http://www.sciencedaily.com/releases/2009/12/091223125125.htm

"When something comes into your brain -- a thought, some sort of stimulus, you see something interesting, you hear some music -- synapses get activated," said Kosik. "What happens next is really interesting, but to follow the pathway our experiments moved to cultured neurons. When synapses got activated, one of the proteins wrapped around that silencing complex gets degraded."

When the signal comes in, the wrapping protein degrades or gets fragmented. Then the RNA is suddenly free to synthesize a new protein.

"One reason why this is interesting is that scientists have been perplexed for some time as to why, when synapses are strengthened, you need to have proteins degrade and also make new proteins," said Kosik. "You have the degradation of proteins going on side by side with the synthesis of new proteins. So we have now resolved this paradox. We show that protein degradation and synthesis go hand in hand. The degradation permits the synthesis to occur. That's the elegant scientific finding that comes out of this."

 

[berkeman]

Mark, I am not sure if I can respond to your observations as I have been severely censured for differing with previous comments or offering my own opinions. I would observe that your comments appear to be your own opinions. I don't mean that in an antagonistic way, but do you have evidence to support your claims?

In saying what I did, I was not suggesting that making a spear point, or affixing it to a stick, is simple to someone who hasn't done it before. That would be a somewhat vacuous claim. Rather, I am suggesting - without evidence it is true - that the mental processes for making a spear are relatively simple by comparison to those required to design and build a jet engine. I think that to be able to design and build a jet engine requires the accumulation of a lot of knowledge and the application of particular modes of thinking/problem solving/conceptualisation that have been developed over many centuries.

I think that building a spear is relatively simple, and in context would have been easily taught to most members of a tribe. Designing and building a jet not so much. I venture therefore that a primitive man of 40 years of age brought to today's world would struggle to be taught many of the things that people of today can do. Whereas, a reasonably intelligent man of today transported to a time 10,000 years ago would be able to learn all of the necessary skills to survive, if he was supported in doing so. And he probably could learn all of the knowledge that the tribe possessed.

Please let me chime in. I agree with Mark's points, and find your posts in this thread a bit strange. What is your motivation for taking this position? And Mark does not have to post peer-reviewed journal article references before you do. You started this thread, so the burden to post scientific references in this debate is on you first.

Also, I think you should rephrase your final question in the post I quoted above -- you should be asking if 100 newborn babies from that long ago were introduced into modern society, would there be measurable differences in their intellectual performance.

 

[Graeme M]

I am at work and cannot respond in any depth. Evo's comment suggests that there is some misunderstanding of my post. I am not suggesting that the brain has changed in recent times, or in response to people being 'smarter'. Nor am I suggesting that people from the past who shared a brain of the same morphology as today were less intelligent. I just don't know enough to make any such claim.

Rather, I am trying to understand the development of the 'mind'. At a very rudimentary level - I am just intrigued.

My first question was aimed at giving me a starting point. That is, when did a modern brain first evolve. I am quite happy with the answer ~200,000 years ago. It's what I thought would be the case. But I didn't know if there was any substantial evidence for this. You have told me that there is. So that's an excellent first step for me.

Mark, I'd like to come back to your comments because that is closer to my main area of interest/curiosity. I shall post later from home.

 

[PeterDonis]

The brain is capable of learning new things without the brain having to physically change.

Just to clarify, by "physically change" I assume you mean "change the overall capacity of the brain". The changes that happen in your brain when you learn something are physical changes; they're just not changes to the overall capacity of the brain, they're changes in what specific information that capacity is being used to store and process.

 

[PeterDonis]

I am trying to understand the development of the 'mind'.

You're going to need to clarify what you mean by "mind", since it's evidently something different from "the biological structure and capacity of the brain". Whatever you mean by it might well be off topic for this forum.

 

[Evo]

Just to clarify, by "physically change" I assume you mean "change the overall capacity of the brain". The changes that happen in your brain when you learn something are physical changes; they're just not changes to the overall capacity of the brain, they're changes in what specific information that capacity is being used to store and process.

Exactly!

 

[Graeme M]

You could be right PeterDonis. My apologies for not grasping that distinction. From my lay perspective I would have thought biological science would also have had an interest in the working of the mind. Perhaps not in the psychological sense, more in the mechanical sense - how does mind arise from the physical function of the brain, and what is the relationship between the two.

Also, you say there are physical changes to the brain when skills/knowledge are learned but not to the overall capacity of the brain. By 'capacity', do you mean size or volume, or do you mean form and function?

 

[PeterDonis]

how does mind arise from the physical function of the brain, and what is the relationship between the two.

This is basically the domain of cognitive science, which is not quite biology and not quite psychology, but something in between. The Wikipedia article actually gives a decent overview:

http://en.wikipedia.org/wiki/Cognitive_science

By 'capacity', do you mean size or volume, or do you mean form and function?

I mean something like what a computer scientist would call "processing power": the equivalent of the specs you would look at when buying a computer, things like CPU speed, RAM, hard disk space, network bandwidth, etc. In other words, capacity for information processing, independent of what specific information is processed.

Obviously this is not something we know how to directly measure for a brain; the best proxies we have for it at present are probably overall brain volume and the surface area and density of convolutions of the cerebral cortex. Those may not be very good proxies, but they have the advantage that we can estimate them from fossilized skulls, so we can track how they evolved over long periods of time.

 

[DiracPool]

My first question was aimed at giving me a starting point. That is, when did a modern brain first evolve. I am quite happy with the answer ~200,000 years ago. It's what I thought would be the case. But I didn't know if there was any substantial evidence for this. You have told me that there is. So that's an excellent first step for me.

Of course, it's first important to define what you mean by modern. I personally wouldn't say that the modern brain appeared or evolved 200,000 years ago, I would say it was roughly 1.8 mya with the appearance of Homo erectus. The cranial capacity of H. erectus and related archaeological artifacts around that time suggest a major bifurcation in cognitive abilities relative to those of more archaic hominins. From there it was a slow, steady evolution of the brain in a manner that's difficult to substantiate archaeologically because we don't have fossilized remains of the soft tissue anatomy of the brain. The best we can do are endocast reconstructions, which only reveal a tenuous geography of the cortical surface. Instead, what we use to try to reconstruct the evolution of the brain/mind connection are archaeological artifacts created by humans and, more recently, genetic studies.

Contrary to Ygggdrasil's claim:

The fact that diverse human populations that diverged earlier than 50,000 years ago share the same brain development and morphology suggests that no major changes have occurred during this period.

...there is ample evidence that the human brain has evolved in the past 50,000 years, and that these changes in brain morphology have been instrumental in the cognitive advances of evolution of human thought. The big leaps did not occur 200,000 years ago with the appearance of "anatomically modern humans;" to think that brain architecture or any internal organ development evolves pari passu with skeletal changes is a naive assumption. The evidence from my research suggests that the major bifurcative changes in brain architecture that coincided with marked changes in cognitive abilities occurred first with the appearance of Homo erectus, as stated above, at 1.8 mya, the next event coinciding with the "upper paleolithic explosion" around 37,000 years ago, and then most recently about 5500 years ago with the appearance of writing and the rise of city/states. This assessment again combines archaeological and brain genetic data.

Again, Ygggdrasil has referenced an earlier thread I commented on and has offered a rebuttal to the genetic evidence. But just because there's a rebuttal to the genetic evidence doesn't mean it's not "evidence" per se, it just means that someone has contested that evidence. I've followed the debate on the microcephaly genes and their relation to brain evolution closely over the past decade, and I feel that research in this area has been stunted due to "culturally sensitive" reasons. Basically, Bruce Lahn and his lab have been unfairly bullied out of continuing their research in this field, and it has subsequently put a chill on other researchers efforts, although they are still continuing. But to make statements such as:

However, this research has been challenged as other methods of examining the data do not find signs of positive selection, and comparisons of people with and without the changes do not show any differences in cognitive abilities or brain size. Thus, it seems like these initial reports were false positives.

...is a short-sighted conclusion, to say the least.

http://forum.ebaumsworld.com/archive/index.php/t-145358.html
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4376118/
http://www.gnxp.com/blog/2006/06/bruce-lahn-moving-on-to-non-iq.php
http://www.wsj.com/articles/SB115040765329081636

Put simply, the human brain is under a continuous evolution and the selective pressure on that evolution has been enormous culturally especially over the last 50,000 years. If you took a newborn baby today and placed him/her in a tribe 50,000 years ago, they would fare just fine. If you took a baby from 50,000 years ago and placed them in a family today, I do not believe they would be able to read or write or do math as we expect children to do today. We only developed that capacity biologically 5500 years ago. All the talk in this thread about the accumulation of knowledge as a factor in advancing the content of human cognition are valid, but this regresses back to the old nature vs nurture argument. The bottom line is that both nature and nurture are needed. We know this from studies of feral children. You can take a modern child with a modern brain, and if they are deprived of cultural training, they don't fare so well.

 

[AlephNumbers]

Bruce Lahn and his lab have been unfairly bullied out of continuing their research in this field

It seems to me that Bruce Lahn was just in a hurry to prove a point. Unless he has hard evidence that the genetic differences in brain size between the Americas, Europe, Asia and Sub-Saharan Africa are a result of recent evolution, then the whole thing seems erroneous. And completely unrelated to the topic at hand.

 

[DiracPool]

It seems to me that Bruce Lahn was just in a hurry to prove a point. Unless he has hard evidence that the genetic differences in brain size between the Americas, Europe, Asia and Sub-Saharan Africa are a result of recent evolution, then the whole thing seems erroneous. And completely unrelated to the topic at hand.

Well, I think he does have hard evidence, or else Science magazine and Nature Reviews Genetics and other publications would not have published these articles, and as far as I know, none of these articles has been rescinded from any of these publications. Look for yourself. What does that tell you? As far as the geographical distribution of the gene presence you refer to, this was an unnecessary inclusion in the early papers, and it is what got his group involved in the controversy in the first place. He later went on to defend himself by raising the flag of "celebrate genetic diversity,"

http://www.nature.com/nature/journal/v461/n7265/full/461726a.html

...and I certainly agree with him, but the connection of advancing the adaptive evolution of ASPM and MCPH1 to geographical/cultural associations was misplaced. There are at least 7 and probably several more microcephaly related genes that interact in complex ways to build and evolve the human brain (and that of all mammals), and for him to imply that there is a connection between these two genes in and of themselves and gross brain size/intelligence differences between various human populations geographically was and is unsubstantiated