Evolution of the Human Mind: Understanding Brain Development Over Time

[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

 

[AlephNumbers]

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 premature and thus, incorrect.

http://chronicle.uchicago.edu/050922/brainevolution.shtml

"The researchers emphasize that very little is known about the impact of these variants. They may not have anything to do with cognition or intelligence."

 

[Graeme M]

DiracPool, that is very interesting. If I can find the time, I will read your references. But if I can summarise, you are suggesting that cognitive improvements over time (eg language development) seem to correlate with changes in the form or function of the brain

I assume this is derived purely from genetic evidence (in terms of the physical architecture) because the fossil evidence cannot show any internal changes. And presumably if there is some controversy those changes are therefore not corroborated by evidence from endocast reconstructions?

Do you think that the appearance of language was a result of architectural changes, or the cause?

Nonetheless, that seems not to bear too significantly on my line of inquiry unless there is evidence that most improvements in human cognition arise from a proven physical evolution. But that may reflect my limited understanding of the topic.

 

[Graeme M]

Mark and Berkeman. You seem to be conferring a different meaning to my comments than I intend. This means I must not be explaining myself clearly, and indeed contributing in this punctuated fashion makes it difficult. I'll try to address your objections, but I am also aware I may stray into breach of policy in doing so. Please warn me if this becomes the case.

The first thing is that the mind experiment of transferring individuals between times is not meant to be taken so literally. Clearly a modern man dropped into some remote land 10,000 years ago is unlikely to survive very long. My analogy was meant more to consider the respective mental capacity of each subject. I simply pose the idea that a man of our time, with the knowledge, skills, problem solving techniques and awareness of history, would - I contend - be able to learn everything there is to know in an ancient society, and fairly quickly. He may not be quite as adept at the subtleties of spear point development and may suffer substantially socially, but I think he could easily master the local knowledge, and would be a genius in terms of problem solving.

I further pose the idea that the ancient man transported to today has none of the benefits of education, knowledge, problem solving techniques or familiarity with complex concepts that a modern man might have. I doubt that he could, even in time, learn much beyond the basics.

I suggest that this is because the entire framework of human knowledge, and the ability to apply that, is conferred to individuals in our time via a range of mechanisms. More complex language that can express more complex concepts, written language, extensive records and the ability to utilise these, an awareness of the nature of the world and the universe at large, and so on. A smart man of today armed with this sort of skillset is not left floundering in attacking quite complex problems.

This framework is taught from birth. I will suggest that this promotes a mode of thinking that initially is not 'natural' or accessible to an ancient man. I am not familiar with how the brain works beyond a basic understanding, but I assume that retention of, and application of complex knowledge and techniques requires quite complex neuronal connections. The process of learning creates and reinforces these, and I also suspect that this is more successful the early in life this is undertaken. I suggest that at 40 years of age, an indivudal would be significantly less able to learn all of the modern knowledge and techniques if he had never been exposed to them before. His knowledge set, his skillset, his very worldview, would not be flexible enough to permit him to do this.

Now I have no evidence of this - it's an opinion only based on my own introspection into these questions. But I hope it explains a little what I was driving at.

Mark, you suggested that building a jet engine requires cooperation between many people, and that is true. But it is something of a red herring. Individually, each member of the team (engineers, designers, etc) would have far more knowledge and ability to apply that knowledge than our ancient man. This seems to be clear from the long term process of development of human knowledge. People don't just 'get' stuff, it's taken a lot of work, thinking, experimentation and so on to learn. I think it takes a rather complex arrangement of 'mind' to be able to construct a theory of relativity, or a great piano concerto, or an insightful social manifesto than it does to make a spear, hunt animals, and worship a sun god.

 

[DiracPool]

Do you think that the appearance of language was a result of architectural changes, or the cause?

That's a great question, Graeme, and really hits to the heart of the issue. Unequivocally, I would say that language was/is a result of architectural changes. Just think about it for a second, why can't a chimpanzee talk? The fact that his larynx isn't descended doesn't prevent him from making utterances that we could interpret as human-like language.

In a similar vein, the fact that Steven Hawking can only communicate through twitches in his cheek can communicate that he definitely possesses human-like language.

The capacity for language preceded the changes in the throat that facilitated more complex and refined expressions of vowels and consonants. This began about about 300,000 years ago, prior to the appearance of anatomically modern humans. However, the context of those utterances was likely restricted to only several word utterances without any identifiable grammatical construction prior to the neolithic revolution.

 

[Graeme M]

DiracPool, that sort of goes to the heart of my question in a sense. I've titled this post 'evolution of the mind'. I don't really know what a mind is, but it clearly arises from the function of the brain. Now, it seems to me that it isn't possible to have complex thoughts, or to develop complex ways of interpreting the world, without language. But language itself has developed over time, which is what I was sort of getting at. Language, and consequently the capacity of the brain to express more complex ideas, has developed over time.

You have suggested that the brain changed to facilitate language before the throat had the ability to form more complex arrangements of sounds. Do you think those changes simply permitted language in itself, or did they gave rise to more sophisticated mental constructions that could be expressed via language?

 

[DiracPool]

You have suggested that the brain changed to facilitate language before the throat had the ability to form more complex arrangements of sounds. Do you think those changes simply permitted language in itself, or did they gave rise to more sophisticated mental constructions that could be expressed via language?

Again, you are asking the right questions...The answer is that those changes did both. There is a very intimate relationship between language, mathematical ability, and logical thought processes. They are all connected through a mechanism of hierarchical sequential processing. If you want the exhaustive details, review Jean Piaget's many books and articles on the subject, I especially recommend, "The psychology of the child" (1969) and "Genetic epistemology" (1971). The generative agent that allowed this hierarchical sequential processing to flourish was the progressive development of the human prefrontal cortex in the rostral forebrain and it's associated connections situated more caudally. My argument earlier relating to the microcephaly related genes is simply that the model is these adaptive mutations in these genes gave the progenitor or neuroepithelial cells more generations to develop "daughter cells" to build a more rubust infrastructure to carry out these hierarchically sequential schemes.

 

[Mark44]

The first thing is that the mind experiment of transferring individuals between times is not meant to be taken so literally. Clearly a modern man dropped into some remote land 10,000 years ago is unlikely to survive very long. My analogy was meant more to consider the respective mental capacity of each subject. I simply pose the idea that a man of our time, with the knowledge, skills, problem solving techniques and awareness of history, would - I contend - be able to learn everything there is to know in an ancient society, and fairly quickly. He may not be quite as adept at the subtleties of spear point development and may suffer substantially socially, but I think he could easily master the local knowledge, and would be a genius in terms of problem solving.

Unless I'm reading you wrong here, you seem to be contradicting yourself, with "unlikely to survive very long" and being able to "easily master the local knowledge". Your basic premise seems to be that the mind of modern man is so superior to that of someone of 10,000 (or whatever) years ago, that it would be very easy for him to quickly pick up everything he needed to know. There are copious examples of people who find themselves in situations roughly akin to those faced by our ancestors -- and who do not survive the experience.

My contention is that the knowledge, skills, problem solving techniques, and awareness of history would be just about worthless to a modern man transported into the long-ago past. How would, for example, an awareness of history help a modern man catch a fish or know which roots could be eaten? What skills does he have that would help him kill and skin an animal to make some item of clothing? How would his knowledge help him find drinkable water in a desert (like the Apaches) or an arid grassland (like the natives of the Kalahari)? How would a modern man learn all these things "fairly quickly" with no knowledge of the language of the people he finds? Do you think they would be willing to expend the extra effort of feeding someone who doesn't know how to hunt or fish, doesn't know which plants can be eaten, can't fashion tools, and otherwise has no useful skills?

 

[Ygggdrasil]

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.

I very much doubt the claim that we only developed the capacity to read, write or do math 5500 years ago. Archaeological and genetic evidence indicates that human populations diverged from each other ~ 100,000-50,000 years ago. A trait that evolved 5,500 years ago would not have time to have spread throughout all human populations. However, the ability to learn reading, writing, and mathematics is universal among humans. Clearly the ability to learn such subjects must have evolved earlier than the point at which human populations migrating to different locations and forming genetically distinct groups (a less plausible alternative, however, could be that such ability evolved independently in all these different populations).

As I mentioned in my previous post, there are very well substantiated non-biological explanations for the fact that some cultures developed writing, reading, and mathematics before others. See, for example, Jared Diamond's Guns, Germs and Steel which focuses on a geographic explanation.

I do sympathize with Lahn because this area is very controversial (see for example, the recent controversy over Nicholas Wade's book). But that controversy is there for good reason. Such findings of recent genetic changes that promote intelligence has enormous social consequences, so researchers must be very cautious to not overinterpret their data. The top journals like Science are often publishing research from those working at the vanguard of their field. They tackle questions that are just on the edge of our capabilities to solve, and in trying to extend the frontiers of science, researchers sometime make conclusions that go beyond the capabilities of their methods. Although Lahn made the claim that there are signs that the ASPM and MCPH1 are under positive selection, other have proposed alternative explanations for his data that do not involve positive selection. Does this mean that Lahn's conclusion incorrect? No, I don't think we have enough information to disprove his claims. However, I also do not thing we have sufficient evidence to support his conclusion either. Finding evidence for selection in genetic data is a difficult problem, and researchers are still trying to figure out better methods to address these problems. Lahn's papers present interesting hypotheses that still require more testing. Furthermore, this discussion about selection does not even touch on the even more difficult problem of determining the biological effect of the genetic variants Lahn describes. Even if Lahn is correct that the variants are under positive selection, they could be under selection for reasons that are completely unrelated to the brain or intelligence.

Thus, it is very premature to use his studies as the basis of an argument that the the ability to read, write, and perform math evolved recently. It is certainly possible that recent genetic changes (< 50,000 years ago) have influence brain development, morphology and function, but as I stated previously, there is no strong evidence supporting such claims yet. Such evidence could come in the future, especially given ongoing efforts to determine the extant genetic variants influencing intelligence and cognition, but as of now we do not have enough evidence to reject the null hypothesis that no significant changes have occurred.

 

[mattt]

I very much doubt the claim that we only developed the capacity to read, write or do math 5500 years ago.

I also doubt it very much. Does not make sense with what we already know.

Archaeological and genetic evidence indicates that human populations diverged from each other ~ 100,000-50,000 years ago. A trait that evolved 5,500 years ago would not have time to have spread throughout all human populations.

Exactly

However, the ability to learn reading, writing, and mathematics is universal among humans. Clearly the ability to learn such subjects must have evolved earlier than the point at which human populations migrating to different locations and forming genetically distinct groups

Exactly.

As I mentioned in my previous post, there are very well substantiated non-biological explanations for the fact that some cultures developed writing, reading, and mathematics before others. See, for example, Jared Diamond's Guns, Germs and Steel which focuses on a geographic explanation.

I do sympathize with Lahn because this area is very controversial (see for example, the recent controversy over Nicholas Wade's book). But that controversy is there for good reason. Such findings of recent genetic changes that promote intelligence has enormous social consequences, so researchers must be very cautious to not overinterpret their data. The top journals like Science are often publishing research from those working at the vanguard of their field. They tackle questions that are just on the edge of our capabilities to solve, and in trying to extend the frontiers of science, researchers sometime make conclusions that go beyond the capabilities of their methods. Although Lahn made the claim that there are signs that the ASPM and MCPH1 are under positive selection, other have proposed alternative explanations for his data that do not involve positive selection. Does this mean that Lahn's conclusion incorrect? No, I don't think we have enough information to disprove his claims. However, I also do not thing we have sufficient evidence to support his conclusion either. Finding evidence for selection in genetic data is a difficult problem, and researchers are still trying to figure out better methods to address these problems. Lahn's papers present interesting hypotheses that still require more testing. Furthermore, this discussion about selection does not even touch on the even more difficult problem of determining the biological effect of the genetic variants Lahn describes. Even if Lahn is correct that the variants are under positive selection, they could be under selection for reasons that are completely unrelated to the brain or intelligence.

Thus, it is very premature to use his studies as the basis of an argument that the the ability to read, write, and perform math evolved recently. It is certainly possible that recent genetic changes (< 50,000 years ago) have influence brain development, morphology and function, but as I stated previously, there is no strong evidence supporting such claims yet. Such evidence could come in the future, especially given ongoing efforts to determine the extant genetic variants influencing intelligence and cognition, but as of now we do not have enough evidence to reject the null hypothesis that no significant changes have occurred.

If we put, say, 1000000 babies from 50,000 or 60,000 years ago, and are raised in todays world, I doubt it very much that we could find any statistically significant difference in their "intelligence" or cognitive abilities with respect to us.

 

[PeterDonis]

Mark, you suggested that building a jet engine requires cooperation between many people, and that is true. But it is something of a red herring. Individually, each member of the team (engineers, designers, etc) would have far more knowledge and ability to apply that knowledge than our ancient man.

Actually, I was the one that made that suggestion about the jet engine. You're correct that the individual humans involved each have a very different set of background knowledge than a human of 10,000 years ago would have. But once again, that background knowledge was not developed by those individual humans; they were taught it. The knowledge they were taught arose from an ongoing process of discovery in which many, many humans participated. So, once again, the greater "complexity of mind" required to build a jet engine, as opposed to a spear, does not necessarily imply greater capacity of a single human brain.

 

[PeterDonis]

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.

This is certainly plausible, but I think it's important to remember that evolution is not the same as "improvement". It's quite plausible that the human brain has changed over the past 50,000 years, or the past 10,000, so if a newborn baby from those times was time transported to the present day, they would be at a disadvantage even given the same environment for development as other newborns. But it's also quite plausible that a newborn baby of today would also be at a disadvantage if time transported to 10,000 or 50,000 years ago and given the same environment for development as other newborns.

In other words, the humans of 50,000 years ago were adapted for that environment; humans of today are adapted for today's. Placing either one into a different environment than the one for which they are adapted would be expected to place them at a disadvantage.

 

[Graeme M]

There are some excellent comments here for me to read and digest further. I thank those who have contributed so far, you have given me some excellent food for thought as well as a lot of further reading.

Mark44 and PeterDonis, the difficulty here is my effort to explain what I am thinking. I do realize my take on this is in all likelihood wrong, but at this stage you haven't shown me whether that is the case because I haven't made my argument clearly. I'll have nother quick stab at it.

I assume that a brain of 20,000 years ago is the same as one from today. That has been largely confirmed by most here though DiracPool's comments suggest otherwise. But for the sake of discussion let's agree that an ancient braqin (20,000 years ago) is likely to be the same as today.

I completely agree that a man of today dropped 20,000 years ago would struggle to survive, if this really happened. For all sorts of reasons including that the locals might simply dispatch him. I also agree that the brain of 20,000 years ago has the same capacity or potential as one of today.

What I am contending is that HOW people think has changed. Yes knowledge has accumulated, but knowledge is useless without a means to apply it. An engineer, or a quantum physicist, must learn both the facts, and the methods for applying those. Teaching techniques have developed over time as we establish better ways to educate. And allied with this is the development of more complex language and other symbolic means to codify complex ideas and relationships, for example mathematics.

I imagine, without knowing what science may say, that a 40 year old brain has set up a pattern of internal connections and representations that are fairly 'fixed'. That is, once you've been taught what and how to think (and I mean this both in terms of specific skills and knowledge as well as more general matters of social relationships and behaviours), it is not easy to make major changes to those. Sort of like old dogs and new tricks.

A person of ancient times would have a way of thinking that has been set by his time. He would know far fewer actual facts and he would have quite limited ways to apply those facts. I think the further back we go, the more limited would be his abilities in this respect. Once we get back to when language had not developed, I imagine his thinking would have been quite rudimentary by today's standards.

Regardless of how the brain is structured or whether it has changed appreciably in the past 50,000 years, it is language that allows us to introspect in more complex ways. It allows us to do complex analytical thinking, it permits us to share knowledge and pass it on, and it enables a greater level of shared understanding and cooperation.

Thus, a modern man with a more developed mind would, if placed in the distant past and given the support to learn local skills and knowledge, be able to do so. I think he may not be able to grasp the nuances of local social customs, but I think he should be able to learn all known facts and apply those. I do not think an ancient person brought into today could do so. But I aghree that 1 or 100000 babies from then raised today should display equal cognitive abilities as a modern person.

I think the mind has developed, or evolved, over time. Which in a mechanical sense means that the brain's processing capacity, while unchanged, is utilised in more complex ways. In a clumsy analogy, I mean that it is like a powerful computer that in the past was used to run a simple program while today it runs a more complex program. However, there is one curious wrinkle to that idea which I think might be sensitive to discuss. I think what holds true due to time, also holds true today.

 

[Pythagorean]

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.

Same goes for a handful of modern people raised off the grid with no education.

 

[Pythagorean]

Actually, are we going too far saying there's no difference at all in the cognitive outcome of somebody from 10k years ago vs. someone today? While we can say evolution likely hasn't occurred in the last 10k years, can we say that significant epigenetic changes haven't?

 

[Graeme M]

Same goes for a handful of modern people raised off the grid with no education.

Yes, I think that is the case.

 

[PeterDonis]

What I am contending is that HOW people think has changed.

And whether this is true (I think it is), and to what extent, and what it means, and all the details related to that, isn't a question of biology; it's a question belonging to some other discipline (such as cognitive science, as I suggested before). Which means it's off topic for this thread and this forum. The original question of this thread was whether the brain itself, its raw biological capacity, has changed; it looks like you have gotten enough feedback on that question. If that's true, then this thread has probably run its course. The question of "how people think", considered apart from how brains have or have not changed biologically, belongs in a separate thread in the appropriate forum.

 

[Ygggdrasil]

What I am contending is that HOW people think has changed.

I'd agree with PeterDonis that this question is beyond the scope of biology. However, I will point out this study that may be relevant to this question:
http://news.sciencemag.org/archaeol...ay-have-evolved-help-our-ancestors-make-tools

 

[Mark44]

There are some excellent comments here for me to read and digest further. I thank those who have contributed so far, you have given me some excellent food for thought as well as a lot of further reading.

Mark44 and PeterDonis, the difficulty here is my effort to explain what I am thinking. I do realize my take on this is in all likelihood wrong, but at this stage you haven't shown me whether that is the case because I haven't made my argument clearly. I'll have nother quick stab at it.

For myself, your argument has seemed clear to me, but what's not clear is on what evidence you base your argument/opinion.

I assume that a brain of 20,000 years ago is the same as one from today. That has been largely confirmed by most here though DiracPool's comments suggest otherwise. But for the sake of discussion let's agree that an ancient braqin (20,000 years ago) is likely to be the same as today.

I completely agree that a man of today dropped 20,000 years ago would struggle to survive, if this really happened. For all sorts of reasons including that the locals might simply dispatch him. I also agree that the brain of 20,000 years ago has the same capacity or potential as one of today.

What I am contending is that HOW people think has changed. Yes knowledge has accumulated, but knowledge is useless without a means to apply it. An engineer, or a quantum physicist, must learn both the facts, and the methods for applying those. Teaching techniques have developed over time as we establish better ways to educate. And allied with this is the development of more complex language and other symbolic means to codify complex ideas and relationships, for example mathematics.

I imagine, without knowing what science may say, that a 40 year old brain has set up a pattern of internal connections and representations that are fairly 'fixed'. That is, once you've been taught what and how to think (and I mean this both in terms of specific skills and knowledge as well as more general matters of social relationships and behaviours), it is not easy to make major changes to those. Sort of like old dogs and new tricks.

A person of ancient times would have a way of thinking that has been set by his time. He would know far fewer actual facts and he would have quite limited ways to apply those facts.

I'm not sure that I agree with "far fewer facts" and "quite limited ways to apply those facts." On what do you base this conclusion? As a counter to your claim of "far fewer facts," and using Aleut and Eskimo cultures as a proxy for early mankind, my limited knowledge of their languages is that they had 15+ distinct words for snow, which suggests a pretty sophisticated understanding of their environment, not to mention that these societies were able to make a living for thousands of years in an environment that none of us participating in this discussion would be able to survive for more than a day or two.

I think the further back we go, the more limited would be his abilities in this respect. Once we get back to when language had not developed, I imagine his thinking would have been quite rudimentary by today's standards.

Regardless of how the brain is structured or whether it has changed appreciably in the past 50,000 years, it is language that allows us to introspect in more complex ways. It allows us to do complex analytical thinking, it permits us to share knowledge and pass it on, and it enables a greater level of shared understanding and cooperation.

Thus, a modern man with a more developed mind would, if placed in the distant past and given the support to learn local skills and knowledge, be able to do so. I think he may not be able to grasp the nuances of local social customs, but I think he should be able to learn all known facts and apply those.

Again, based on what evidence? What you're calling "nuances" I am arguing would be incorrect answers in the pass/fail exam of life. I have questioned your thinking in some of my previous replies, none of which you have replied to. Why do you believe that a modern man would be able to learn "all known facts" and apply them? Please back up your claims with some evidence.

I have given reasons for why I believe this is not plausible, based on the evident ability of those early people to survive in a harsh environment, and the equally evident inability of modern people to survive outside of civilization.

My take on your claims is that you place very little significance on what early mankind had to know to survive, such as what plants could be eaten or used for medicine, how to capture or kill animals for food, how to make clothing, how to make shelters, and many other skills. Do you know how to do any of these things? I would consider your opinion more valid if you were speaking from experience. On the other hand, if someone has no knowledge of, or appreciation of the difficulty of these skills, it is very easy to describe them as easily learned.

I do not think an ancient person brought into today could do so. But I aghree that 1 or 100000 babies from then raised today should display equal cognitive abilities as a modern person.

I think the mind has developed, or evolved, over time. Which in a mechanical sense means that the brain's processing capacity, while unchanged, is utilised in more complex ways. In a clumsy analogy, I mean that it is like a powerful computer that in the past was used to run a simple program while today it runs a more complex program.

Not a good metaphor. Assuming we're talking about the same computer, it would have the same instruction set then and now, so it would not be able to run a more complex program now.

However, there is one curious wrinkle to that idea which I think might be sensitive to discuss. I think what holds true due to time, also holds true today.

A question that @berkeman asked earlier is: what is your motivation here?

 

[Graeme M]

I agree that this has now strayed to a field outside the scope of biology. The original question was around the extent to which the brain had evolved over time, in particular whether it had changed substantially recently (being around the last 10-20,000 years). My specific interest is more to do with cognition I think, and this question was more to set the scene for further inquiry. My best guess based on what I'd read was that the brain hadn't changed much and that the potential to do what people do today had existed in distant times. Notwithstanding DiracPools comments, which I will follow up on, it seems that is the case.

For my purposes of learning about the mind and cognition, the basic fact is that an ancient brain (circa 20,000 years ago) is the same as a modern brain, as best we know.

Mark44, a part of the problem here is my use of language. When I say I "think" something, or venture an opinion, I am simply stating what my own consideration suggests to me. I don't know if I am right or wrong. Nor do I have a specific axe to grind, although I think I do have some broad idea in mind. My motivation is simply that I am interested in how the human mind works and why it might differ from that of another species. I have come at this with absolutely no knowledge beyond some high school biology and a few books I've read in the past. It's just a subject of interest, I don't think I am trying to defend a particular position.

My broad idea is that I think a modern mind is a more complex thing than an ancient mind. I don't think it makes sense to say that 'knowledge' has increased. What is knowledge? Is it just facts, or is it the way in which the mind makes use of those facts? I think, with no evidence beyond my own observations, that being able to know what plants to eat, or how to kill an animal, is a relatively simple set of skills.

By the way, I'm not specifically talking about any old Joe Average. I am more getting at the capability of the mind to grapple with complex ideas and develop new models of the world and how that filters down to Joe Average. Perhaps the words knowledge and mind are synonymous in this context, but I think there is a distinction. A modern mind does more in that sense than an ancient mind. That's my thinking on it, not a stated fact.

Think of it like this. If an astronomer were asked to learn all the facts available to an ancient - how to build a boat, how to cook food, how to worship a god, how to make a spear, how to track an animal - could he do it? With say an intensive 12 month course, with appropriate tutors and hands on experience and so on, could he do it? I suggest he could do a pretty fair job of it. He may not acquire the skills well enough in that time, but I think he would essentially understand the details and the processes. But could an ancient man be placed in a modern context, and with 12 months education make any sort of reasonable fist of any modern undertaking - eg cosmology, surgery, neuroscience? I suspect not. But again, that's just my thinking, I'm not saying it is so. I will have to read and inquire more into this side of things.

 

[AlephNumbers]

with 12 months education make any sort of reasonable fist of any modern undertaking

Of course not, that is absolutely ridiculous! The amount of education needed to understand neuroscience cannot possibly be compressed into a 12 month course. One needs to have a solid foundation in many other subjects- biology, the English language, chemistry, to name a few.

 

[Evo]

Think of it like this. If an astronomer were asked to learn all the facts available to an ancient - how to build a boat, how to cook food, how to worship a god, how to make a spear, how to track an animal - could he do it? With say an intensive 12 month course, with appropriate tutors and hands on experience and so on, could he do it? I suggest he could do a pretty fair job of it. He may not acquire the skills well enough in that time, but I think he would essentially understand the details and the processes. But could an ancient man be placed in a modern context, and with 12 months education make any sort of reasonable fist of any modern undertaking - eg cosmology, surgery, neuroscience? I suspect not. But again, that's just my thinking, I'm not saying it is so. I will have to read and inquire more into this side of things.

Could a modern adult man, with no previous education, given 12 months, make any sort of reasonable "fist" (your word, I have no idea what you meant) of any modern undertaking - eg cosmology, surgery, neuroscience? I suspect not. What you are comparing makes no sense. The astronomer didn't learn what he knows in only 12 months. He's had a lifetime of learning. Do you see your error in thinking here?

If you took a newborn from 10-20k years aqo and raised him in today's society and educational system, he'd have the same abilities to learn as a modern infant.

Edit, I see AlephNumbers beat me to it.

 

[Graeme M]

Evo, Aleph, the concept I am trying to express isn't coming through. I am not making sense to you, but perhaps the concept I have in mind is not sensible either (or so trivial that you haven't considered it). I will have another go in my lunch break, but I accept I am beyond the scope of this forum in doing so. if you wish to indulge me further I appreciate it, if not that's fine.

 

[Mark44]

By the way, I'm not specifically talking about any old Joe Average. I am more getting at the capability of the mind to grapple with complex ideas and develop new models of the world and how that filters down to Joe Average. Perhaps the words knowledge and mind are synonymous in this context, but I think there is a distinction. A modern mind does more in that sense than an ancient mind. That's my thinking on it, not a stated fact.

Think of it like this. If an astronomer were asked to learn all the facts available to an ancient - how to build a boat, how to cook food, how to worship a god, how to make a spear, how to track an animal - could he do it? With say an intensive 12 month course, with appropriate tutors and hands on experience and so on, could he do it? I suggest he could do a pretty fair job of it.

We'll have to disagree on this, I guess, but my answer would range from a flat "No" to "Probably not." Stephen Hawking counts as an astronomer, no? I don't think he would last one month, let alone twelve.

Your hypothesis here is somewhat akin to saying "If I had wings, then I could fly." First off I don't have wings, so this syllogism also doesn't fly. As for "all the facts available to an ancient" - the hypothetical interloper wouldn't just stroll down to the library and pick up a book conveniently titled "Compendium of All Known Facts." There would not be any central repository for these facts.

There's no guarantee that any people the modern man meets would greet him with open arms to share their hard-earned knowledge. In fact, if he were to alight in one of many places on Earth even as recent as 100 to 200 years ago, the people he met would be more likely to kill him and eat him than to share their hard-earned knowledge with him. After all, he isn't in their family or their clan, so he's fair game.

Have you ever built anything with your own hands? Built a fire without using matches? Caught a fish? Found your way in a place with no roads or trails? Built an igloo during a snowstorm? Please correct me if I'm wrong here, but you seem to assume that these are relatively trivial tasks that any intelligent person could perform, and that said person could learn "all available facts" in a short time. To me, and again, correct me if I'm wrong, this sounds like it comes from someone with little or no knowledge of the difficulty of these undertakings.

He may not acquire the skills well enough in that time, but I think he would essentially understand the details and the processes. But could an ancient man be placed in a modern context, and with 12 months education make any sort of reasonable fist of any modern undertaking - eg cosmology, surgery, neuroscience? I suspect not. But again, that's just my thinking, I'm not saying it is so. I will have to read and inquire more into this side of things.

 

[PeterDonis]

At this point the original question of the thread has been answered, and we are straying far beyond biology. Thread closed.