I always try to see the human brain from an evolutionary perspective.
What the human brain added was a way to simulate other brains, because of growing communication ability for coordination's sake. It's basically a way to recognise smart freeloaders. E.g. men trying to sweet talk a woman for sex (and impregnation). He will make a lot of promises but how surely can you depend on him? It's of vital importance you know so you don't get duped.
So the human brain is an advanced bullshitmeter and bullshitter in an arms race, and this brain simulation machine has all kinds of unexpected side effects. At least, based upon some clues I read from some biologists, I came out on that understanding. If this has some truth, based on the world today, we still can get a lot better at it.
Having a mammalian cortex (or avian cortex equivalent) is what give you the ability the predict. The cortex is the prediction machine - capable of overriding our evolutionary-earlier reactionary behavior with planned behavior based on prediction.
The ability to predict is surely what drove development of the cortex, since the benefits are massive - allows you to know what comes next when you hear the roar of a tiger, or see a poisonous snake, or make a plan, rather than waiting until something bad is actually happening to you.
Parts of our cortex specialized to social behavior would have come later. I doubt bullshit generation/detection would have been a specific driver though! As girls attracted to "bad boys" attest, the urge to merge is far more basic than that.
What the human brain added was a way to simulate other brains, because of growing communication ability for coordination's sake. It's basically a way to recognise smart freeloaders. E.g. men trying to sweet talk a woman for sex (and impregnation). He will make a lot of promises but how surely can you depend on him? It's of vital importance you know so you don't get duped.
So the human brain is an advanced bullshitmeter and bullshitter in an arms race, and this brain simulation machine has all kinds of unexpected side effects. At least, based upon some clues I read from some biologists, I came out on that understanding. If this has some truth, based on the world today, we still can get a lot better at it.