Why is the Human Brain so Big?
Dr George Christos, July 2018

The answer is simpler than you might think.

Here is a video of my theory. Rebecca Ronita helped me produce the video.
Written by me. Transcript follows:

Why is the Human brain so large?

The human brain is at least twice the size of what it should be compared to other mammals taking body size into account.

Why is this so?

Some theories suggest that environmental factors like fire, intense climatic changes, like draughts and floods, which would have lead to famine and new challenges forcing our brains to expand, to adapt to these changes, but these theories do not explain why other mammals did not undergo a similar rapid expansion in brain size. 
Other theories suggest that the development of language and social structure drove the rapid growth of the human brain. There is also a theory about changing our diet too.
Theses explanations are all in a sense encompassed within the framework of memetic evolution, the evolution of memes or ideas, which started evolving when humans started to communicate with each other, and started the need to copy each other, and  develop new ideas.
In the book “the meme machine” Susan Blackmore suggested the human brain had to expand in order to be able to copy, whereas George Christos in “The Memetic World” has suggested that creativity was equally important.

But something subtle is still missing according to Dr George Christos.

Humans needed to copy each other. This would have been important for survival. If we did not copy some clever trick off someone else, such as learning how to start and maintain a fire, or knowing what food to eat we may have died. 

In addition, humans evolved to become more inventive, innovative and creative, so they could out do each other, again something which enhances their own survival as a self, family or larger social group.

Let us not forget that humans were also in competition with each other as well.

Just try to imagine what it would have been like before....in more primitive times.

If a 'neighbour' knew how to make a club or a knife, and we did not, we may have been killed by them.  They would just take whatever we had for themselves.
Our history is saturated with violence between humans. That violence would have been on a much smaller scale in the past, involving family units and then groups of people.
George Christos suggests that it was the intense and violent competition between humans which forced our brains to explode in size, beyond any other creature on Earth.
Humans with little brains, who were incapable of copying creating or innovating, would have been slaughtered by other humans. Let us not forget that policing and laws are relatively new things, starting only a few hundreds years ago. Before that it was essentially a lawless society.

If you wanted to take something from someone, you just did it and possibly even killed them, or they might come kill you to get it back or get revenge.
Human violence may also explain why there are not any species similar to homo sapiens in the biological world. Humans literally obliterated all the other species similar to us including the Neanderthals.

Dr George Christos