This topic is being discussed elsewhere, but withing the wider framework of how personality develops in humans.   If our Big Brains work in the way they do as the sum of evolutionary processes on mankind, and our little brains work the way they do as as the sum of lifetime waking experiences, then a number of useful insights are given into how we really work.   

Alex recently published the following post on a different forum.   I copy it here (with his permission):

It seems to me that the Big Brain/little brain theory explains everything from excessive Puritanism to the other extreme, fascism and the holocaust.

Little Brain takes in feeds from outside like, normally languages, social order, attitudes and then, among its other functions, Big Brain processes and refines our attitudes to them.

Little children instinctively hit each other to protect their property and presumably this is a Big Brain natural protective response. Then parents, who Little Brain has fed to Big Brain are creatures of influence, tell children its wrong to hit others and you hurt them.

I assume Big Brain assesses this data and decides on its worth. The intelligent big brain assesses this information and makes a decision. Mommy is right and I have to find other ways of dealing with this OR Mommy is a killjoy and I love making little Johnny next door scream with pain so I'll carry on and take my chances.

Its about choice and that doesn't necessarily go the 'right' way. Some choices are evil but the evil is a chosen path.

Now on the other side of the coin I suspect Big Brain can malfunction or be idle so that when Little Brain feeds it an external factor it needs more information from the Little Brain in order to do anything. Is there a point where Mass Hypnosis a la Hitler can force Little Brain to overpower the filtering and decision making of Big Brain so that an alternative message can over power decency, reason and logic that you learned as a child?

Eg, (Hitler Message) Killing people is bad unless those people are Jews because they are a threat to us.

Enough Germans leapt on this bandwagon to suggest that a powerful message send via Little Brain can subordinate natural feelings learnt earlier about right and wrong.

Religious fanatics, acolytes of any extreme political creed etc who appear to receive info through the Little Brain portal and do nothing to refine it are those suffering from Brain 'skip'.