"Enlighten me then with your wisdom. Where did this increased brain size and capacity come from then?"No can do for several reasons. Firstly, I don't know. That's why I have continued to raise it as a question.
Secondly, you are completely resistant to anything anyone else proposes that doesn't fit in with your latest idea fix and favourite social/economic theories.
For example you continue with claims about brain size as if that was the only factor.
I seem to recall that even mice have more brain mass per body mass than Man !!
It's what's in the brain that's the question and mystery.
All the "scholarly" speculation about what early hominids began to do or not, millions of years ago is just that ... speculation.
It raises more questions rather than explain existing ones.
All the higher animals including Man, have basic "semi instinctive" reasoning ability and a built-in body system of extraordinary intelligence ... depending how you define intelligence.
The question is why does Man have an additional function which clearly exceeds what is needed for ordinary day to day living.
The simple answer is we don't know how or why Man appeared with a uniquely different brain. Not just in size but in function.
Now all I can do is for the umptheenth time is point you to my question as per this post
https://hotcopper.com.au/posts/46612364/single.