Human brains of course exhibit a high degree of neuroplasticity. But this has more to do with learning, acquisition of new skills, altering conditioned habits and thought patterns, etc.
Willfully directed neuroplasticity is a thing—but the directed ends chosen will be heavily implicated in one's genetic proclivities.
Rewriting basal motivations probably isn't entirely impossible, just understandably difficult… and strikes me as a morbid act of egoic self-destruction, which one should be wondering why they're bothering to do. You're better off embracing who you are and figuring out how to get what you want, rather than cauterizing yourself into changing what you want.
Because they're fairly self-evident at an early age, and seemingly operate at a deeper/visceral level of interpersonal compatibility than other typological measures. It's more vital than socionics intertype relations, for instance.Any particular reason you think they're inborn vs learned?
And more generally speaking I'm largely a genetic determinist, as growing evidence continues to mount in favor of that outlook. We find more and more that "nurture" & "environment" are largely irrelevant; people 'become' what they were already born to be.
Environmental factors would certainly play a role in neurosis, i.e. when the primary instinct isn't being satisfied, or when too much demand is being placed on the tertiary instinct.Maybe nature is responsible for the instinct order, but nurture plays the dominant role in our levels of development or health...