Humans used to have significantly bigger brains 35,000 years ago. Can you imagine?
https://www.discovermagazine.com/planet-earth/the-human-brai...
https://www.discovermagazine.com/planet-earth/the-human-brai...
It could well be that our brains are more efficient (or more specialised) than earlier human / proto-human brains.
Given the prodigious energy expenditure of the human brain, any gain in efficiency or shedding of unnecessary capabilities could well be a net win.
But with the advent of proto-civilization, the calculus changed...
Larger heads might have been facilitated by a larger pelvic girdle (this seems to be the case in Neadnderthal skeletons AFAIU), which is an adaptation which would enable large (and possibly inefficient) brains, but at a cost for bipedal mobility, speed, and/or efficiency.
Supposing a later competitor emerged with 1) smaller and 2) more effcicient brains as well as 3) narrower hips, then the previous advantage would become a (comparative) liability.
It's a bit like Clayton Chistensen's Innovator's Dilemma: evolving yourself (or your species) into a corner. Advantageous for a while, but ultimately maladaptive, and hard to back out of.
As with my other comments here, all but entirely conjecture.
I'm mostly aware of this dynamic from h. sapies and h. neanderthalensis (or h. sapiens sapiens* and h. sapiens neanderthalensis* comparisons. In a nutshell, Neanderthals were in numerous ways the apparent heavy-duty / high-output model, Sapiens the more efficient / economy model. Neanderthals had larger muscles, shorter limbs (less speed but greater strength, simply on leverage), and larger cranial volumes. All of which would have, everything else being constant, increased overall energy demands.
Mind: this is all my own conjecture, though I wouldn't be surprised to find some literature suggesting similar mechanisms.
Where Neanderthals were competing against other mammalian species and each other, the differentiation was apparently favourable. Possibly also in an ice-age climage.
With Sapiens on the scene ... Neanderthals largely disappeared from the record, though in all likelihood also interbred with Sapiens to some extent. For whatever the reasons, the Neanderthalic adaptations seemed less suitable than the Sapiens ones. The presumption is that this was a fitness selection, though it could well have been other factors (mating preferences, superior numbers for Sapiens, dumb luck and/or chance).
But ... in general, while bigger can seem better and more appealing for various reasons, it often is not, and adaptations which require higher energy or have a higher minimum sustaining requirement ... could well prove to be less suitable especially where the environment itself is in transition, or where resources are highly marginal.
There is a fair bit of research into the loss of vestigal function, particularly among sequestered cave populations such as blind fish and invertebrates. It turns out that visual processing has high energy demands, and in an environment in which sight conveys no advantage, lack of sight is actually advantageous, as it reduces neurlogical metabolic load (by as much as 1/5 to 1/4 if I'm recalling my sources correctly).
In the case of "Dragon Man", we're looking at a new instance and have little data to go on. But other homo variants and general evolutionary trends suggest at the very least possible directions.
Nothing that "lacks intelligence" (a monkey, a person with dementia, a person who reads slowly) behaves all that similarly or is actually lacking the same single thing that causes them to "not be intelligent".
It's not a pleasant subject, but we should not be blind to it, especially when underground and even open air market human trafficking still happens in many places around the world.
There's dozens of easy non-intelligence hypothesis that can be readily tested: Maybe the skull was larger because it helped balance the weight better for swinging through trees, maybe it was more protective against impact. We can sit around and make up lots of stories to explain this.
Besides, human brains are about the same weight as walruses. If size = intelligence, I'd expect to be chatting with walruses on the phone, working with them at the office... Or what about elephants? Their brains are 4 times bigger!
There's no way it makes sense upon any cursory analysis. It's just a carryover from phrenology.
Your understanding of “intelligence” is quite anthropo-centered, of the XXth century-office-work style…
Nothing ever _requires_ that intelligence has to express itself in a consistent/compatible way across species and their own environment.
Perhaps, for instance, some large brain species did not “evolve” as homo sapiens did, because they were more intelligent of their surroundings.
https://www.scientificamerican.com/article/does-brain-size-m....
No, clearly it's the money. They go in with phrenology bias and can't really do solid science. They even use IQ numbers which have been shown to correlate with parents income more than almost anything else.
They even mention the career of hedge fund managers, the classic career along with real estate and politics of dullard rich kids.
As the article contributes they then point out everything that I did. I don't know if the editors wanted this style or what.
It opens with paragraphs of clearly specious bullshit then says it's bullshit then has a concluding statement about how it's nonsense.
Second to last paragraph
> So it is not brain size, relative brain size or absolute number of neurons that distinguishes us. Perhaps our wiring has become more streamlined, our metabolism more efficient, our synapses more sophisticated.
Yeah, duh, of course it's more complicated then "durr it's bigger". And of course it's all skewed by the instrument of measure.
It's probably really stupid dumb things like the nuances of human emotions and our success in transmitting them. What sets is apart from other animals likely isn't what 30 year olds can do but what 30 week olds can
(If we use the conventional definition of "intelligence" as "capability to learn and acquire new skills".)
If cities are more economically productive than separate villages, because they increase communication among people... well, how much higher-capacity a communication channel than brains literally wired together? You can do better than bike lanes, people.
Assuming that brain size is correlated to intelligence implies that, on average, taller people are more intelligent!