The next part is the limbic system, what we commonly call the subconscious part of the brain. It contains emotions and instincts. Everything that makes humans different from other animals, our essential core personality. And it still works the same way it did before we fucked up and invented agriculture, which is why people do so many dumb things that make no sense in a modern context.
The newest system is the thinking part of the brain. It deals with numbers, cause and effect, anything that requires conscious thought. It can reprogram the subconscious which is how we learn things. It is also extremely slow and energy intensive compared to the emotional part of the brain, which is why most people do not use it unless absolutely required. It is not fully developed before the age of about 25, which helps to explain teenagers.
NPCs use primarily the emotional part of the brain. They don't think, they just feel. They carry out automatic scripts.
What I have observed is that high-amygdala people use the thinking part of the brain more. I believe it has to do with a heightened sense of danger, which prompts us to develop new and better modes of operation because the ones we have are obviously not sufficient. Small-amygdala people do not see the coming dangers. They are physically incapable of perceiving them. I have yet to see a serious study look into this connection, but I would bet money on it being correct.
https://www.youtube.com/watch?v=hg6XUYWj-pk
I don't know if I really look out for danger (subconsciously) though, I just really enjoy trying to identify all aspects of cause and effect for just about anything. It's literally like playing games or solving puzzles to me, which I consider entertaining. I generally don't feel threatened by any of the potential doomsday scenarios either, they're just part of the intriguing game of life to me.
NPCs are definitely a thing though. Always had a hunch that something was "odd" about some people (who consider me just as odd I suppose) but it's interesting to see that there are actual studies on this. Taking offense to anything is just the dumbest concept imaginable for me, although the impulse makes sense given our previous exposure to predators.