Why do people in Shin Sekai Yori die if they kill other humans?
I remember that during the anime they go through some ritual, but why does that ritual work? What is that ritual exactly? Is it something religious or is it just portrayed religiously but has scientific reasons it works? Do they psychologically affect the subconscious of humans? Is it a religious "magic" that does the trick? What gets triggered in the human brain after when people try to kill other humans? By what mechanism do they die? Why is the ritual needed?
Also, what was the name of this thing? Was it death of shame? Why is that the name?
NOTE: I have watched (not recently) the whole show, so no risk of spoilers. Sorry the story is not very fresh on my mind.