Trust hypothesis

Developmentally, we are programmed to start learning to let go of many things during our young adulthood.This learning happens slowly, and in stages. The letting go is also done in that way, to ensure there is no sudden shock.
We learn to stop relying on our parents, economically and emotionally.
We learn to stop having completely organized lives that school and college gave us.

I might have just listed just 2 things, but I think you would know that both of those things, especially the first incorporates a billion smaller things within itself.

So as we grow older, most of us learn to save bits of ourselves. Little bits here and there which is not for anyone but ourselves. We learn that as we grow older, people and things we love don't stay forever, and every time someone leaves, they take a bit of our hearts with them.
Be it a break up, or later on, when a child moves out of the house.

When we're born, we're all born with a lot of ....trust issues (:P). Have you noticed how tightly a baby holds on to you, or how loudly it screams when someone new try to pick it up (most babies). We're not born very trusting.
Somewhere between our second year and fifth year, we learn to trust implicitly. To the extent that our parents have to repeatedly tell us not to talk or accept anything from strangers. This trust usually lingers on till we start learning to let go.

I'm hypothesizing that our trust development is divided into 3 stages:
1. No trust (0 to 2-3 yrs)
2. Implicit trust (3 to 16)
3. Conditional trust (18 onward)

Have you noticed that in the movies, the guy or the girl with major trust issues is usually the one who had a 'dark past'? Maybe a kidnap, or drowning, single parent, lost as a kid, whatever ... those character sketches are usually portrayed as people with trust issues.

I think that when something so huge happens when we're young, the implicit trust is shaken to an extent that we revert to stage one. The reverting may happen completely, or just in parts based on the severity of the issue.Stage 3 requires a lot of learning, and is attained in very rare cases when they are already almost there, precociously.
So these people go back to stage one, and have to do their learning from there. I guess that's why dealing with them, especially if you're in some sort of relationship with them is a tad difficult.
Not that they won't ever trust you, but it takes longer to pass stage one, then in that period of the relationship when you get them to learn to trust, they cross a period of stage 2, very cautiously. If anything happens then, even the slightest question of trust, they revert to stage 1. But if you hold on long enough, they will get to stage 3. And might just make it worth the wait :P

This is my hypothesis ;)