Racial differences...

[Viking]

Everything comes at a price. That's why we are not as fast as a cheetah and as strong as a horse, nor is a mollusc as creative as us. They are not worthwhile.

Abstract thinking and complex reasoning benefit you, in your environment. To others, it may be a detrimental waste. It can be a waste in general, or it can even get in the way of a more useful mode of thinking, perhaps more verbal, communicative oriented. The ability to understand how to get to that fruit that's hanging just out of reach is as important as the ability to understand and settle in-group conflict. Both intelligences vary between populations and within populations, and even the spread of variation within the population differs.

Capacity for empathy in some environments means people cooperate better, increasing their survival chance. In other environments, it may be detrimental. Agression rates may vary. Abstract thinking varies.

But just how expensive is gaining that little extra bit of intelligence anyway? It doesn't have to cost much.

Humans are not that weak; I don't know how strong an animal of with our build-up could be in theory, but it's not long ago that we were hunters. Still some humans can hunt down their prey using sheer strength:



And this is a specie that has "focused" on brain power.