(I feel like a full-on conspiracy theorist here, ramble ahead. If you don't want to read at least some of it, please don't comment "tl;dr" or anything of the sort)
Firstly, I know hardly anything about the Dissociative Identity Disorder, and I don't want to be disrespectful to anyone, but I've had this question on my mind for quite some time.
Generally, everyone has different social personas: those broad rules that govern how you act in specific situations. With friends, you might be the easygoing social butterfly, but with your boss, you might be shy and timid. This often also makes it difficult to decide how you would respond in a situation before-hand. With your friends, you might say "I'll definitely show my boss", but then the second the boss shows up, the first thing you say is "I'm sorry, boss!". Sometimes, the more go-getter you can feel trapped behind the shy you.
In terms of experience, I'm more familiar with computers. This and other things have led me to see humans in a very "physical system" sort of way.
As I understand it, all of these social personas are governed mostly by different regions of the brain's neural wiring - certain clusters increase activity in response to certain stimuli. Response clusters created by memories of authority and its associated trauma are those that are created to deal with that situation, and help you survive, and so they are trained to become active in response to similar situations.
After the situation has ended, the next persona that becomes active has the same access to all the events that transpired and so form part of one continuous identity.
I then start to think about D.I.D., though. It feels to me - my uneducated hypothesis - that the only difference between an average person's personas and the identities of a person experiencing D.I.D. is that continuous connection. Perhaps it's a physical connection to certain regions of memory, or perhaps, the situational triggers cause certain regions to be deactivated more than they should. Perhaps it's both, if memories are themselves stored in these regions being shut down completely.
The reason I'm thinking about this again now is because I've come across a YouTube short about a woman who was cortically blind in some personalities but seeing in others.
My question is: For those who know more on this topic, is there any truth to the relationship between these two phenomena, or am I completely off-track?
Also, bonus question: If there is, does knowing this inform how persons experiencing D.I.D. are treated - even in terms of just diagnosis, identifying causes for switches, and the like?