None of this information is secret or remotely hidden: all of it can be confirmed by doing simple online searches and reading reputable sources. I am always astounded how many people think we only use 10% of our brains or want to categorize others based on “left” or “right” brain activity. This video does an excellent job of summing up actual research and confronting the top 7 myths about the human brain.
The human brain’s development to its current power and effectiveness came with other biological costs, for instance, a reduction in muscle strength (Bozek,Wei et al, 2014), in the course of our evolution.