Genetic variability aside.It just seems to me that the brain is one humdinger of an ineffective way to store information. I mean if God had intended us to remember things she would have given us computer plug-in or other physical ways to keep track like say a pad of paper and a pencil - instead of relying on such foolish things as memories.
So what is the brain designed to do– some would say nothing. Cause there is no design involved. But what is the brain capable of handling. Well our brains are excellent at detecting danger and problem solving dangerous situations we can see (bears lions and tigers). Not so good at situations that are out of sight(Global warming and nuclear holocaust). The brain seems to be a very clever way to create new things with out having created the ability to see the consequences of those new things (DDT, Plutonium)
In general our brains seem to be really handy out helping us to survive – but not so useful at storing information. Luckily for us the human race invented writing and then computers to help us with that particular function.
Maybe God felt sorry for us cause we were with out nasty teeth or claws, thick skin or even fur. So she gave us creativity instead cause it would help to balance the scales.