I don’t think this question has a known factual answer.
I enjoyed an observation made in “Walking with Cavemen” (at least, I’m pretty sure that was where I saw it)…
One episode talked about the development of the first stone tools, and the huge advantage this gave our ancestors at the time.
The next episode started out by fast-forwarding 1 million years, and pointing out that the humans of the time were still using the exact same tools.
Their take on this was that the earliest stone tools were basically a product of evolution - like a bird building a nest or a beaver building a dam. Only later did we evolve a brain capable of what we would think of as actual invention, where we imagine something and then set out to make it a reality.
Okay, so given the valuable replies can I assume that an answer to the question about what came first, the tool or the brain, can only a hypothesis, since there isn’t any empirical data to back up either side? And there isn’t likely to be any future data to back up any side since the tools in question couldn’t possibly still exist (discounting the remote possibility that they could be preserved somehow - which I am willing to concede).
So the next time a professor claims to that the theory that the tool came first I can call BS on him and explain to him that there is no data (only questions and guesses) to back up his hypothesis?
I might concede that a larger brain could evolve from increasing social activity. So maybe the answer is that the brain came first. But that is only a hypothesis, with no evidence to back it up.
Okay, so now. Chicken or Egg? Hee hee. Just kidding. I’m sure that’s been beaten to death.
Oh, and one small point. We aren’t fully omnivores. We are evolving to becoming omnivores. Omnivores still require meat. We don’t.
Evolving to become omnivores? No, it doesn’t look like there is any evolutionary mechanism regarding our diets in action at the moment. And omnivores do not require meat. It is just that they can digest meat, unlike a horse. However, getting the full variety of required amino acids in the amounts we need them while avoiding all animal products requires a lot of knowledge and balancing of a variety of foodstuffs that are not always available to people without supermarkets. Being a healthy vegan requires a fair amount of work while complete nutrition becomes a no brainer if you get a bit of chicken and cheese now and then.
Now you’re jumping around. We had moved on from the OP to talking about specific hypotheses about the growth of the brain AFTER tool use had been invented. The way you state it, I think one must assume that the brain came first. Otherwise, the tool would just be a stick on the ground.
The egg came first.
We are not evolving TO BECOME anything. Say that to your prof and he’ll flunk you! 
Yeah. Many creatures must have had a brain capable of at least some thought long before one variety of creature started using various natural objects for particular purposes.
I saw some show discussing early (or were they current?) h/g societies and their diets, and the claim was that the gatherers supplied 80% of the diet, while the hunters provided 80% of the nutrition.
I really don’t get the “tools allowed brains to get bigger” part of the question. At all. Does somebody know what the OP is trying to get at?
As a WAG I’d say his real purpose is to show that God did it.
Not necessarily. I believe that God created evolution. And I dont’ think that God created the universe as brand new. He created it as if it had evolved. He created the Earth with strata and a history, even if the history was completely fictional. So if it were proven that the tool came before the brain, it wouldn’t really threaten my biblical beliefs. Now, let’s not go off on a tangent here. This isn’t GD. I’m really interested in the scientific facts here.
You give yourself too much credit for the ability to use a tool. Ever eatch a river otter? Damn thing is a rodent isn’t it? Either way, it’s no ape. And it sees a rock as a tool to open up its food.
It doesn’t take a genius to bang some rocks against nuts.
Bear, an otter is, I believe, the largest member of the weasel family, not a rodent (which are vegetarians).
Loopy, I believe the point about tools required for brain development is based on the idea that tools were required to get the kind of high-quality nutrition necessary for really big brains to develop. Personally, I find this highly questionable - there are many reasons why a population could experience comparatively lavishly rich nutrition.
Prisoner, your god must be quite a prankster.
It all started with the startling appearance of a big, black monolith amongst a group of cavemen. (Kubrick, 1968).
See my post #2 in this thread.
Brain cells are very expensive to maintain. Even at rest they require something like 20x the energy that muscle cells do. If you’re going to grow a big brain, you have to be able to feed it, and with something more than grass. Seed grains work OK, but you need farming to make sure you have some of that all year round. Tools allowed early hominids to hunt and/or scavange meat. One hypothesis is that the earliest tools were used to get at bone marrow, which is often not utilized by other predators or scavengers, thus allowing early hominids to exploit a niche no other animal was exploiting.
This makes it hard to take you original question seriously. I retire from the thread.
Er… I just wanted to say, I was looking through the Camel Toe thread, and then I saw this one, and I thought: “Oh, I know the answer to that!”
Different kind of tool altogether. :o
Sorry.
Hmm. I guess the way the idea has been bandied about further in the thread, it looks a tad Lamarcian. Also, bigger doesn’t always equal smarter (the folding connectivity of the cerebral cortex is just as important, if not moreso, than the overall mass of the organ; and it requires no more caloric expension to take a dump as solve differential equations). Dolphins have pretty big brains (with greater mass per brain than we do), but there apparently was no selective pressure on them to develop tools. As long as they do one thing well (catch fish, maybe) tools are superfluous. What’s all that grey matter in the Dolphin’s head being used for, then? I assume it must have a lot to do with their complex system of vocalizations and social structure, as well as their migratory expertise.
I guess the “marrow niche” hypthesis is as plausible as anything, but still, the causative connection between brain size and tool culture seems like a bit of a leap from there. There must have been many selective pressures to surmount, and niches to exploit, before you get from the “bash bone and root out marrow” phase to agriculture, cities, etc.
What is Lamarckian about what I’ve been posting? And yes, brain interconnectivity is as important, if not more so, than size. But don’t underestimate the added calories needed to grow and maintain those interconnections. They don’t come for free.
Oh, not really what you said; I must confess I’ve been skipping around, mostly reading the OPs posts rather haphazardly, and not paying cose attention. It’s my short attention span, and I’m not making much of a serious critique of what you’re saying.
This would explain why it apparently took two million years and a number of hominid species to make the trip. However, marrow is not an unexploited resource. (In the greater scheme of things, are there any unexploited resources?) Hyenas have jaws designed to break long bones and digestive systems that can take care of whatever comes downs the pipe and there is evidence that early humans and hyenas lived at the same times and in the same places.