Do you believe in the missing link theory? Actually did they not just find some really small person with similar skull structure?
Also maybe climate change played a role on which species got to develop and which did not. As life grew increasingly easier for us (less dependent on instincts) maybe our brains began to develope in that fassion.?!

*shrugs* too

Dreaming: Right vs. Left Brain
Left - right- or ambidextrous?