Once again, evolutionists have had things wrong and have been misrepresenting the data. It had been assumed that intelligence was based on cranial capacity, and evolutionary fitness came about from having a larger brain. But it turns out that things are much more complicated than that, and the body would have to evolve in order to accommodate a larger brain.
Creationists do not have to come up with such cockamamie schemes.
You can head over here to read the rest of, "Brain Size: Another Evolutionary Assumption Shot in the Head".