I came across this article which states that brain takes about 20% of the body's energy. This is quite a lot compared to its size. Somewhere I read that even if this is a lot, this must be an absolute requirement otherwise by the theory of evolution, such high energy requirement brains would already have been eliminated.
My question is we know evolution is never stationary, so what is the recent trend (last 4000-5000 years) in the usage of brain energy? To me only 2 cases are possible (in an evolutionary stable sense):
- We are evolving to require less brain power for the same functionality, but the size of functionality remains same (i.e. we are able to think the same thing with same power requirement).
- We are evolving to require more brain power for the same functionality, but the size of functionalities increase(i.e. we are now able to think the bigger things but the power requirement increases).
I might be wrong in the above 2 statements or it may seem redundant, but I am drawing parallels to IC's here in a broader sense.
Also can these generalisations be extended to the evolution of animal brain also?
Any kind of speculative answer based on logic would also be nice.