Questions for Creationists: Human Brain Size

[Notedstrangeperson]

Anthropologists uses two definitions, one for anatomically modern humans, (AMH) and another for behaviorally modern humans. (BMH) Obviously, we evolved to be AMHs before evolving to be BMHs.

Apparently that isn't the case. Some argue it was the other way around.
Buuuut that's another topic ...

 

[juvenissun]

Well, of course for me the most important aspect is the religious one - humans are defined as those animals that have been given a soul by God, so that would be all people alive today, and I don't know exactly when God gave the first soul, (when Adam, the transitional ape that crossed the line to being human, lived). If I had to guess, I'd say maybe 100,00 years ago? But that's just a guess, since souls tend to not fossilize well. : )

For physical attributes, from a layman's standpoint, I'd go by encephalization quotient, which is simple and distinguishes us from all other animals.

However, I need to be clear that I'm not an expert, and that is a "person on the street", common answer. Those kinds of answers should always be remembered to be incomplete, and not to ever suggest that they are as good as the actual definition used by experts.

Anthropologists uses two definitions, one for anatomically modern humans, (AMH) and another for behaviorally modern humans. (BMH) Obviously, we evolved to be AMHs before evolving to be BMHs.

AMHs go by a bunch of anatomical features (including brow ridges, encephalization quotient, a chin, and so on), which evolved gradually and not all on same schedule, with some appearing sooner, some later. Hence the many smooth transitional fossils. Trying to draw a sharp line there is like trying to draw a sharp line between when a room goes from being "freezing cold" to being "too hot". AMH gradually appeared, with the transition being mostly done by around 200,000 years ago.

BMH is defined by spoken language, which also likely appeared gradually (from basic sounds, to a few words, up to language today), but of course that is harder to test because words don't fossilize very well before writing developed (also gradually, as can be seen).

I have enough sense not to disagree with those who know the subject much better than I on this or anything else. I am an expert in one field, and will disagree with anyone there if I think they are wrong, but it's not anthropology.

Papias

Is this a bad (to very bad, even useless) criterion? Does EVERY voice uttering animal have some type of language system? How do you distinguish human language system from, say chimps language system? And where is the fossilized record of any language system?

 

[juvenissun]

Well, of course for me the most important aspect is the religious one - humans are defined as those animals that have been given a soul by God, so that would be all people alive today, and I don't know exactly when God gave the first soul, (when Adam, the transitional ape that crossed the line to being human, lived). If I had to guess, I'd say maybe 100,00 years ago? But that's just a guess, since souls tend to not fossilize well. : )

For physical attributes, from a layman's standpoint, I'd go by encephalization quotient, which is simple and distinguishes us from all other animals.

However, I need to be clear that I'm not an expert, and that is a "person on the street", common answer. Those kinds of answers should always be remembered to be incomplete, and not to ever suggest that they are as good as the actual definition used by experts.

Anthropologists uses two definitions, one for anatomically modern humans, (AMH) and another for behaviorally modern humans. (BMH) Obviously, we evolved to be AMHs before evolving to be BMHs.

AMHs go by a bunch of anatomical features (including brow ridges, encephalization quotient, a chin, and so on), which evolved gradually and not all on same schedule, with some appearing sooner, some later. Hence the many smooth transitional fossils. Trying to draw a sharp line there is like trying to draw a sharp line between when a room goes from being "freezing cold" to being "too hot". AMH gradually appeared, with the transition being mostly done by around 200,000 years ago.

BMH is defined by spoken language, which also likely appeared gradually (from basic sounds, to a few words, up to language today), but of course that is harder to test because words don't fossilize very well before writing developed (also gradually, as can be seen).

I have enough sense not to disagree with those who know the subject much better than I on this or anything else. I am an expert in one field, and will disagree with anyone there if I think they are wrong, but it's not anthropology.

Papias

Why don't you just say: "I don't know"?

 

[Papias]

juvi wrote:

Is this a bad (to very bad, even useless) criterion?

No, it works very well, allowing the experts to make clear distinctions and map out these changes over time, in ways that are agreed upon based on the evidence, regardless of the different religions and worldviews of the experts. And to think that you, who have shown over these threads that you don't understand even the basics of anthropology, are critizing criteria that not only work well, but have led to advances in knowledge.

Does EVERY voice uttering animal have some type of language system? How do you distinguish human language system from, say chimps language system?

If you were a biologist or anthropologist, you'd know the answer to this. The different vocalizations of animals are easily distinguished from the syntax and other features of BMH language by the experts in the field. Chimps don't have language, but are certainly closer than other animals, especially when taught sign language by us.

And where is the fossilized record of any language system?

Did you read my post? I said it doesn't fossilize well. Indirect evidence, such as art and organization, is used to estimate spoken words.

Why don't you just say: "I don't know"?

Did you read my post? Is that not what I said in the very post you quoted, when I said:

Papias wrote:

However, I need to be clear that I'm not an expert, and that is a "person on the street", common answer. Those kinds of answers should always be remembered to be incomplete, and not to ever suggest that they are as good as the actual definition used by experts.

Papias

 

[juvenissun]

I guess now is about the right time to close this thread.

 

[Notedstrangeperson]

15 pages of ... nothing much. Shame it never really went anywhere.

 

[juvenissun]

15 pages of ... nothing much. Shame it never really went anywhere.

Yes, it does a little bit.

We need to find ONE clear and definite beginning of modern human, not a transitional gradual change. Because human is exponentially different from all other animals in what he can do. One example I used here is to raise and to use fire.

Your analysis/classification is good. But it is only a way to study animals, not human. There is a huge gap in between them which can not be shown by morphology. That is why God makes a breath onto human, but not on His other creations. Through your study, we can clearly see what that breath is about. It is on what human does, but not on what human looked like.

So, what we should do is to make a positive link between what human did, with what human looked like. You can not just work on the latter. Think it this way, if human extinct today, what is the key to find any evidence related to human 200 m.y. later? Not by fossil morphology, but by something like bricks, plastic tools, etc.

 

[mark kennedy]

Naraoia, from the common forum sent me this link, thought it might be of interest in this discussion.

The size and surface area of the mammalian brain are thought to be critical determinants of intellectual ability. Recent studies show that development of the gyrated human neocortex involves a lineage of neural stem and transit-amplifying cells that forms the outer subventricular zone (OSVZ), a proliferative region outside the ventricular epithelium. We discuss how proliferation of cells within the OSVZ expands the neocortex by increasing neuron number and modifying the trajectory of migrating neurons. Relating these features to other mammalian species and known molecular regulators of the mouse neocortex suggests how this developmental process could have emerged in evolution.​

Development and Evolution of the Human Neocortex

I have the PDF somewhere but it's been a while since I read it. Anyway, here is another one, this is more complete and puts together the time line.

Evolutionary Forces Shape the Human RFPL1,2,3 Genes toward a Role in Neocortex Development

I'll check back later and see if this generates any interest.

 

[juvenissun]

Naraoia, from the common forum sent me this link, thought it might be of interest in this discussion.

The size and surface area of the mammalian brain are thought to be critical determinants of intellectual ability. Recent studies show that development of the gyrated human neocortex involves a lineage of neural stem and transit-amplifying cells that forms the outer subventricular zone (OSVZ), a proliferative region outside the ventricular epithelium. We discuss how proliferation of cells within the OSVZ expands the neocortex by increasing neuron number and modifying the trajectory of migrating neurons. Relating these features to other mammalian species and known molecular regulators of the mouse neocortex suggests how this developmental process could have emerged in evolution.​

Development and Evolution of the Human Neocortex

I have the PDF somewhere but it's been a while since I read it. Anyway, here is another one, this is more complete and puts together the time line.

Evolutionary Forces Shape the Human RFPL1,2,3 Genes toward a Role in Neocortex Development

I'll check back later and see if this generates any interest.

All these info are fine. The problem is that we do not have brain fossils.
The breath from God not only gives human a spirit, but it MUST cause the human brain to be the one we have. We can see that human brain is different from chimp brain. But science-wise, that is all we have. There is no transition on brain tissues.

 

[mark kennedy]

All these info are fine. The problem is that we do not have brain fossils.
The breath from God not only gives human a spirit, but it MUST cause the human brain to be the one we have. We can see that human brain is different from chimp brain. But science-wise, that is all we have. There is no transition on brain tissues.

Well, we are getting some pretty interesting insights into what would have had to happen. Evolution is a process, natural selection is an effect and paleontology deals with a lot of fragmentary bones. With genetics you are looking at a cause of the differences in no uncertain terms. That is what ultimately has to settle this origins debate from a scientific point of view.

We do have human and chimpanzee brains, genes involved in brain development can be identified and characterized. For me, this is the logical place to look for a cause and effect relationship effectively demonstrating whether or not it is even possible.

Grace and peace,
Mark

 

[JVPITER]

Well, we are getting some pretty interesting insights into what would have had to happen. Evolution is a process, natural selection is an effect and paleontology deals with a lot of fragmentary bones. With genetics you are looking at a cause of the differences in no uncertain terms. That is what ultimately has to settle this origins debate from a scientific point of view.

We do have human and chimpanzee brains, genes involved in brain development can be identified and characterized. For me, this is the logical place to look for a cause and effect relationship effectively demonstrating whether or not it is even possible.

Grace and peace,
Mark

Doesn't the chart "Fossil hominins: Cranial capacity vs time" show that, as an historical fact, brain size increased in overlapping ranges all the way from australopithecus up to modern humans? Doesn't this show that, whatever the cause was, its possible because it actually happened?

 

[juvenissun]

Doesn't the chart "Fossil hominins: Cranial capacity vs time" show that, as an historical fact, brain size increased in overlapping ranges all the way from australopithecus up to modern humans? Doesn't this show that, whatever the cause was, its possible because it actually happened?

Yes, but you missed the point.

We do not have: 0 human > 0.3 human > 0.7 human > 1 human.

We have: 0 human > 1 human. Fossil record does not address this point. The question is still an old one: What is human?

 

[juvenissun]

Well, we are getting some pretty interesting insights into what would have had to happen. Evolution is a process, natural selection is an effect and paleontology deals with a lot of fragmentary bones. With genetics you are looking at a cause of the differences in no uncertain terms. That is what ultimately has to settle this origins debate from a scientific point of view.

We do have human and chimpanzee brains, genes involved in brain development can be identified and characterized. For me, this is the logical place to look for a cause and effect relationship effectively demonstrating whether or not it is even possible.

Grace and peace,
Mark

Yes, genetics is wonderful.

However, it has a fatal insufficiency: We can not study genetics of extinct lives. From that point of view, the valid time range for any genetic discovery is awfully short so it is not useful to address evolution problems in any convincing manner.

A naive question from me (I don't know the answer) may demonstrate the problem: why can't we get any reliable genetic information from a dinosaur bone? Or, this one may be better: do we know any genetic information of Neanderthals?

 

[JVPITER]

A naive question from me (I don't know the answer) may demonstrate the problem: why can't we get any reliable genetic information from a dinosaur bone? Or, this one may be better: do we know any genetic information of Neanderthals?

We don't get DNA from dinosaur bones because we don't have any dinosaur bones. We only have fossils of dinosaur bones, which means all the organic material like bone has been replaced by rock. Rock doesn't have any DNA.

And yes we do have genetic information about Neanderthals:

In 2004, Neanderthal ancient mtDNA was partially sequenced in the HVR region for following specimens: Feldhofer 1, Feldhofer 2 from Germany; Mezmaiskaya from the Russian Caucasus; Vindija 75, Vindija 77, Vindija 80 from Croatia; Engis 2 from Belgium; La Chapelle-aux-Saints from France; El Sidrón: 441, 1253, and 1351c from Spain; and Rochers-de-Villeneuve from France and Riparo Mezzena.

In 2009, six Neanderthal mtDNA full sequences were done and published in the NCIB Genebank listed as Homo sapiens neanderthalensis complete mitochondrial genome from two studies. The mtDNA genetic diversity in Neandertals 38,000 to 70,000 years ago was about one-third of modern humans. The effective population of Neandertals was smaller than modern humans and great apes.The fossil ages of the five dated Neandertal sequences and a human-chimpanzee divergence of ~6 million years.

 

[JVPITER]

Yes, but you missed the point.

We do not have: 0 human > 0.3 human > 0.7 human > 1 human.

We have: 0 human > 1 human. Fossil record does not address this point. The question is still an old one: What is human?

Yes, we do have 0.3 human and 0.7 human, in terms of brain size (and many other anatomical features). That's what the chart shows -- a gradual progression, with no clear dividing line separating modern human from its predecessors. This pattern is what is expected if humans evolved from non-human ancestors.

"What is human" is crystal clear: you are a human, I am a human, we all are humans with a specific average brain size and a specific anatomy. The problem is determining whether an extinct species is human, because there are no clear boundaries, jumps or gaps that divide them from modern humans -- as expected if humans evolved.

 

[mark kennedy]

Doesn't the chart "Fossil hominins: Cranial capacity vs time" show that, as an historical fact, brain size increased in overlapping ranges all the way from australopithecus up to modern humans? Doesn't this show that, whatever the cause was, its possible because it actually happened?

No. As a matter of fact I'm convinced that chimpanzee ancestors are being used as transitional fossils. Even if they are not there is a cause and effect relationship that has to be established for an explanation of a phenomenon to be considered 'scientific'. I don't think it is wise and certainly not scientific to conclude that an ape brain can triple in size, divide into two hemispheres, mesh the neurons to twice the density of apes unless they know the cause.

As far as the fossils, I've seen the charts and I'm not impressed. When you follow the evidence it is far less compelling then we are being told. As always, I reserve the right to remain unconvinced.

 

[shernren]

I don't think it is wise and certainly not scientific to conclude that an ape brain can triple in size, divide into two hemispheres, mesh the neurons to twice the density of apes unless they know the cause.

(emphasis added)

Huhhhhhh.

Actual chimp brain, for reference:

As far as I know, it's not just apes, all mammals have brains with two hemispheres.

Dude, do you actually check what you post?

 

[JVPITER]

Doesn't the chart "Fossil hominins: Cranial capacity vs time" show that, as an historical fact, brain size increased in overlapping ranges all the way from australopithecus up to modern humans? Doesn't this show that, whatever the cause was, its possible because it actually happened?

No. As a matter of fact I'm convinced that chimpanzee ancestors are being used as transitional fossils. Even if they are not there is a cause and effect relationship that has to be established for an explanation of a phenomenon to be considered 'scientific'. I don't think it is wise and certainly not scientific to conclude that an ape brain can triple in size, divide into two hemispheres, mesh the neurons to twice the density of apes unless they know the cause.

As far as the fossils, I've seen the charts and I'm not impressed. When you follow the evidence it is far less compelling then we are being told. As always, I reserve the right to remain unconvinced.

Chimpanzees are already plotted on the chart, in the bottom right corner, in red:

There is a crystal clear trend in cranial size going upwards to the right from australopithecus through to homo. At what point in time are you suggesting the trend jumped back down to a modern chimpanzee level, remembering that "Natura non facit saltum"? Five hundred thousand years ago? A million?

This trend is not a scientific "explanation". It's an observed fact. You may not personally be happy with the proferred explanation, but that does not change the fact that cranial capacity trends upwards with overlapping ranges all the way to modern humans.

In any case, neuron density is a factor known to exhibit a very large range of variation both within species as well as between them -- exactly the sort of feature that natural selection can act on effectively. And size -- of individual organs or the whole organism -- is something we know is very amenable to selection: think chihuahuas and great danes.

Cheers

 

[MarkRohfrietsch]

Thread closed as requested by the original poster.

Mark
Staff Supervisor.