Why brain was protected with hard skull

New research shows that, as with muscles, the more you use a part of your brain, the larger it will get. London taxi drivers have very large hippocampi - the part of the brain that deals with spatial mapping. Also like muscles, as you use a particular part of your brain, more blood is pumped to that area to provide energy. Finally, as with muscles, the more you use your brain, the better it works.