Why do some systems have doubles?
Well, we can't speak for other systems, but for our system we have several different types of doubles.
Double type one: Different person, Same Source
Double type two: Same person, Different source
What does this mean? Well, Double type 1 is exclusive to Introjects, but introjects can also have double type 2's. I'll use an example to explain more about double type 1:
We have several Harry Potter fictives (fuck JKR) For this we're gonna look at Harry Potter and Harry Black.
Harry Potter: Was the first of the two that showed up. Is sourced from Harry Potter during his 5th year. He handles the depression and is very quiet and reserved for the most part. He stays in his room and rarely fronts unless to talk to his dad (Sirius, in another system)
Harry Black: Showed up several months after Harry Potter. Is sourced from Harry Potter during his 5th year. Changed his name to both better diffentant between him and Harry Potter, but also to match his dad's name (Sirius in another system) He holds a lot if anger, and is a lot more out going, he is quick to get angry, and fronts a lot more compared to his brother (Harry Potter).
Why is this is helpful for our system? Well it takes two aspects of the same character and uses that to help the system. They are both sourced from the same character, but often preform completely different roles.
Type 2 doubles are NOT exclusive to Introjects, these are "Same person, Different source" which is a slightly misleading name for it- let me explain. (For context most, if not all, of us have exomemories and exotrauma. Most of that parallels what the body has gone through because the brain believes it's easier to process when it's a "fictional scenario". And because it mostly parallels the body's trauma, most of these exomemories aren't canon)
Okay, so when a headmate is ignoring and pushing away exomemories/not processing exomemories, that the brain assigned to them, the brain will often make a duplicate of that headmate, except it'll be a younger version of them, often when they were actively experiencing that trauma. So that there is a version of them that will deal with or push that headmate to deal with that trauma.
So "Same person, different source" they are the same person just at different points in their life and the younger one is sourced from that headmate not the OG character is that makes sense?
Why have multiple alters in one role?
Again, we can only speak for our system, but we are Polyfragmented, so we always have multiple people in one role. This is because all of our headmates have more than one role. So they way the roles combine, work together, and how the headmate uses their role, is very different per headmate. For example:
Headmate 1 is both an anger holder and a depression holder: This headmate might isolate in anger, stew for several days or weeks ans then blow up when they are finally over it
Headmate 2 is both an anger holder and a trauma holder: This headmate is a lot more reactive, blows up at smaller things, and it is often trauma motivated
Headmate 3 is both an anger holder and a trauma holder: This headmate is a lot more quiet and reserved, but gets very angry, but instead of taking it out on others, they take it out on themself.
You see? Each headmate processes things differently and treats their role differently. Even if they have the same roles as another headmate, they'll act and treat their job completely differently.
titsay
theartofmadeline
stormborns
jacobvanloon
blakekathryn
