Note: This happened just by chance and I didn’t realize it until I saw the picture. Just the very tip of her tongue was protruding, the way cats often do, and I was hoping to capture that.
You’ll probably have to rotate the picture; try as I might, I could not get it to appear in Image Shack the right way up.
I guess you haven’t been following this (side) discussion.
It began with me responding to someone posting a link to another report of the same research, which I said was clearly bullshit. I repeat. It is clearly bullshit. Just because a conclusion is reported in Science Daily, it does not follow that it is true. These people may know about paleontology, and how to measure fossil eye sockets, but they clearly do not know much about visual neuroscience. You can’t validly infer anything about the size of visual processing areas in the brain from the size of the eyeballs.
If there are other sorts of evidence (as this report hints) suggesting that Neanderthals devoted more of their brains than we do to visual processing, then I would be interested to know about it. I will not be at all surprised, however, if it turns out that the path from this other evidence (if it exists) to the conclusion about brain area sizes depends on similarly invalid reasoning (and similarly unwarranted assumptions about the neuroscience of vision).
The description of the research at your link makes yet further bullshit claims. It says Neanderthals needed more visual processing areas because they lived at higher latitudes where light levels are lower. This a non-sequitur. Visual processing areas of the brain are not there to amplify a weak signal, they are there to analyze the visual stimulus (and to control visual behavior) regardless of its strength. More visual brain areas might buy you a more sophisticated analysis, extracting more types of information from the stimulus than you would otherwise get, but they can’t make a weak signal stronger. Come to that, even if they were amplifiers, there is no good reason to think that more brain area devoted to the task would amplify more strongly. Their argument also fails to take account of the fact that we homo sapiens, with our allegedly smaller visual processing areas, can see, and generally manage, perfectly well in northern latitudes, even ones considerably further north than where the Neanderthals lived, and have been doing so since the prehistoric times when we out-competed the Neanderthals.
The claim that having larger visual areas in the brain would leave less brain area, and thus brain “power”, for other sorts of cognition, is largely bullshit too. On the one hand, there is very little direct correlation between the mere size of brain areas and how much processing they can get done. (One supposes there must be some relationship at some deep level, but it is not one that is straightforward, or very apparent at all at our current level of understanding.) On the other hand, “visual” areas of the brain are not, in fact, solely dedicated to analyzing visual input, but play a major role in many other aspects of cognition too. Brain functions are not nearly as neatly or as completely segregated by area as this this argument seems to assume.
It may be the case that Neanderthals developed bigger eyeballs in order to gather more light in dim conditions (like the tarsier does), and if this was for seeing better during twilight rather than during the night, the fact of their having evolved further north might just be relevant. However, again, nothing about the amount of the brain dedicated to vision follows from this, and, again, we homo sapiens seem to be able to see perfectly well, and to have thrived, in northern latitudes, even with the puny eyeballs that we have.
Sure. However, the longer you survive, the more chances to produce offspring you have (up to a point). And if you’re part of a species that cares for its young, then their chances of survival improve if you live longer.
It’s thought that Neandertals diverged from our common ancestor about 400-350 thousand years ago, right? “Modern humans” are generally regarded as being those from the last 200k years. Clearly, brain sizes between H. sapiens and the Neandertals diverged quite a bit: File:BrainTree.pdf - Wikipedia . Are you saying the difference developed entirely in the 150-200k years between the split with Neandertals and the emergence of “modern” humans? That for the past 200k years, H. sapiens have not evolved in terms of brain size?
Relax, dude. Did you not see the smiley? Yes, I agree it looks like bullshit.
AGuy: Yes, the lines that led to Neanderthals and moderns diverged about 500k years ago, but that doesn’t mean the folks wandering around 500k years ago were Neanderthals. They were probably H. heidelbergensis. Think about it. Humans and chimps diverged about 6M years ago, but the common ancestor of us both at 6M years ago was not a chimp (or a human). You don’t see recognizable Neanderthals in the fossil record until sometime between 250k and 200k years ago.
AFAIK, modern brains are the same size they have been for 200K years. If anything, they may be a bit smaller.
Hey, I was the guy who posted it, with the link under the words “or some such shit.”
Meaning, for the record:* I* started it :), and I thought it was bullshit (or, bollox) also.
Actually, that subject was discussed in a thread several weeks ago when that Eticle first came toight. Seems like a huge lrap based on the meagerest piece of data.
Well, alright, but, smiley or no, I do know how else you thought I might interpret “Guess you didn’t get the memo”, with a link to Science Daily" otherwise than as “Clearly you are ignorant about this latest information, which shows you are full of shit”. The winking smiley looks like you are mocking me, not mocking the contents of the link.
In fact, of course, I had got “the memo”, or at least was fully aware of the information contained in it, and was responding to precisely that.
I guess I missed (or forgot) the relevant thread you say there was earlier. If I had known about it, maybe I would have interpreted your words, and smiley, differently… but frankly, I am still not convinced that there is any other reasonable interpretation to give them.
[Moderating]
Relax, dude.
Colibri
General Questions Moderator
Of course… these changes are gradual. At some point you’d have to call them something like “proto-Neandertals,” but you know what I meant. It just seems improbable to me that **all **of the brain size differences between Neandertals and modern humans developed in the first ~200k (or 300k?) years of separation from our common ancestor, but our brain sizes have remained stagnant for the past 200k years.
What do you base that on? Is the fossil record really robust enough to say that with any certainty? It’s just hard for me to believe; for millions of years, the trend in our ancestors has been towards larger brains. How can we explain that trend reversing over the last 200k years?
You know, that does not help me relax. John got unwarrantedly snarky with me, but he has backed down and I got my irritation of my chest. I am pretty sure no rules have been broken or even slightly bent. I was done and I am pretty sure John was too. The hi-jack, such as it was, was over.Telling me to relax now just irritates me again.
OK, my bad for an ambiguous smiley. Sorry about that. I didn’t think that it could be interpreted different ways, but reading it now, I see that it can.
Have a drink on me!
AGuy: I think the term “proto-Anything” is not very scientific as it implies that evolution is evolving towards something, which we know it’s not. Whatever those folks were, they were a population in their own right, some of which evolved into Neanderthals and some of which probably did not.
As for our immediate ancestors having slightly larger brains, I’m going from memory. Hence the “may be”. Also, humans today come in a much larger variety of shapes, with many smaller in overall body size than our 200K years ago ancestors, so our average brain size is almost certainly smaller than theirs.
Natural selection does not have some kind of goal, it is driven by species adapting to the requirements of their environment, the more effective mutations tending to live longer and breed more successfully. Early hominids gained advantage by having bigger brains, but it reached a point where the human brain became ridiculously large and complex with respect to the needs of the early humans: it was over-adapted and the humans were too successful. Evolution rested on its laurels, so to speak, and the brain began to shrink a little. Why would it do that? IIUC, the present form of the brain consumes around a fifth of our overall metabolism, a larger brain would use more energy to no particular net benfit, so smaller brains would win out simply by being more efficient: a thing not needed would tend to be culled.
As to the OP, one might look at eye placement. Humans in the wild are a mid-level predator, meaning they can also be prey animals. The eyes are placed for good stereo (attack) vision but also for pretty good peripheral (threat) vision, which is accomplished in part by eye movement. Most other mammals have either wide field or deep stereo but not both. The broad eye opening that allows for the wide field of view through scanning consequently results in the exposed sclera. The human brain puts an enormous effort into visual processing, at the expense of auditory and olfactory, which might explain why the eye opening developed the way it did.
No. “Too successful”, “over-adaption” and “resting on laurels” do not make sense.
That’s not correct. If ever there was an apex predator, it is us. We (“in the wild” or not) can kill pretty much anything, and very rarely are preyed upon.
The article by Pierce, Stringer and Dunbar can be read here
I am very impressed with the quality of Chris Stringer’s work in this field, and I’d be very interested to find that he is guilty of publishing ‘utter bollocks’, although I suppose it might be remotely possible.
Well, plenty of experts (including Ian Tattersall and Erik Trinkaus) have used the same term I did, you’ll see if you search with Google Scholar. I think you’re reading too much into “proto” if you think it necessarily implies a directed goal is involved. In this context, it just means we see the beginning signs of something that is about to come along (since we have the benefit of hindsight in the matter)
You seem to be making some pretty definitive statements based off of what seems to me to be pretty scant evidence, though (including that last statement). How many samples do we have to go by from around the 200 kya time period? Not enough to draw many strong conclusions about fairly variable characteristics like average population height, I imagine: List of human evolution fossils - Wikipedia
Yes, I know these terms are in common use, but your last sentence explains exactly why they should not be. Everything is always evolving, so everything would be a “proto-” something. It also detracts from the fact that whatever population existing before Neanderthals, many of them would not have evolved into Neanderthals and so they were not proto-Neanderthals at all. Not to mention that some of them evolved into us, since we are talking about the common ancestor of both species.
Keep in mind that there were very few individuals of our species in that timeframe. And if you go a bit further, to about 70k years ago, we appear to have gone through a population bottleneck and there may have been only a few thousand individuals in our entire species. We wouldn’t expect there to be anywhere near the variation we see today.
Also, Link.