by request, here’s the 750, more or less, words version. By
Morgaine Swann The human brain evolved in 4 layers. First came
the brain stem which controls breathing, metabolism, all the
functions that don’t require conscious thought. Scientist Carl
Sagan called the next layer the Reptilian brain, or R-complex. A
reptile has only fight or flight responses. It goes forward to
food, flees from an enemy or fights to the death. Its only
emotion is rage. Its only function is survival. When threatened,
it bites. Next is the Limbic, or mammalian, brain. It contains
instinct (feeding, fighting, fleeing, fu*king) and emotion. It’s
social – mammals raise their young, unlike reptiles abandoning
their eggs, and they live in groups to increase their chances of
survival. Paul D. MacLean, creator of the Triune Brain model,
said that everything in the limbic system is either “agreeable”
or “disagreeable.” It isn’t capable of higher functions like
logical reasoning, it only feels and reacts. The newest part of
the human brain is