Larger brains dont help if most people keep just using a small part of it.
Everyone uses all their brain, if you are referring to the old claim that we only use 10%. It is not a good idea to make claims about brain use though when supporting communism.
I know that #LSD consumption activates large parts of the brain & that many people never use LSD so they miss out on this chance to grow consciousness: https://bit.ly/1qjEE1M