pol did a ton of research on this and i was around at that time - a lot of the research ended on layered personalities. They would intentional force stress to fracture the personality and induce various layers with different programming. I'm just stopping by to say hello and keep us moving, I will do my best to recall more and provide as much info as I can.
https:// monarchprogramming.wordpress.com/category/alters-and-triggers/