While we speak of dissociation as if we know what it is, I don’t believe that we do. We only truly know simply that dissociation happens.
We do know that many brain operations that involve more than one brain region often have a ‘point’ where the operations – not unlike a chain of activity – can be broken and dissociated one from the other. Researchers look for these points because they are like road signs. They provide us with specific information regarding specific regions – what they do, how they operate, what signals them, and which brain regions they are in connection to and cooperate with.
I will have much to say over time about dissociation because I suspect it is an occurrence held in common by all so-called ‘mental illnesses.’ Because all supposed mental illnesses are directly tied to what is called “reproductive fitness indicators,” so too must dissociation also be tied in the same way.
The range and spectrum of special giftedness within our species is broad and fascinating. I believe that the ability to dissociate is a survival gift.
So, please look forward to future postings on the subject.
Stop the Storm 
The ability to dissociate is certainly a survival mechanic, though its usefulness could be debated – the same way researchers now consider depression a holdover from ancient survival mechanics.
If “avoidance of pain” or “avoidance of stress” or simply “completion of a specific task or goal” could be considered ‘survival’, then yes, dissociation can be very useful for people with abnormal self-regulatory systems / skills. However I personally feel its usefulness is outweighed by the disruption it causes in the very ‘self’ that is being suppressed, and the lengthy ‘recovery time’ it costs. (This is my experience of it, at any rate; I wouldn’t be surprised if others’ experiences were different.)
From my experience “ability to dissociate” is not my concern. Dissociation was simply built into my body-brain as I grew within an early environment that — simply — created these patterns within me.
The survival level dissociation originates in for severe infant abuse and trauma survivors is within most centrally the operation of the autonomic nervous system (with its connections to CNS-brain).
The stress-calm response of STOP when there is too much GO simply preserves life by conserving resources via “dissociation.”
I do not see dissociation as a defense in any other way than this just described. I see it as being just another alternate root-way to process self-body throughout ongoing experience.
For those formed as I was, dissociation is as much a part of our ongoing experience as any other part of our body is.
I believe we need to learn how this extra “sense” we have operates.
mental illness is a catch phrase for what is not understood
Oh you NAILED IT!!!