(I like this thread topic. And having recently thought about it... an adapted diary post!)
So what is it in people (what psychological constructs exist) that drives these resolutions of cognitive dissonace?
(Rephrased questions: What psychological constructs cause cognitive dissonance? What is it in people that moves cognitive dissonance to resolution?)
The constructs are best expressed as the interlinking "filters" that make up the structures used to process and bring meaning to our present. Filters, meaning the heuristics that we use to organize the data we gather... but in this case, heuristics includes thought/mind as a whole. Cognitive dissonance suddenly changes and destabilizes our filtering processes (ie: groupings, conceptual underpinnings, etc), which results in confusion, stress and anxiety. The mind attempts to return to equilibrium (ie: a functional state). We rebuild our structure (reframe), remove the influence (denial), or fragment our constructs (double standards).
I say this in extremely general terms. Forms of dissonance come from this interplay, and range from childhood training, self-justification for actions and group identification. And an infinite more, probably.
The resolution is simply the rewiring of our mind to accept (avoid) disharmony. To ask what is done is to ask how the mind wires itself. The best analogy is to use 'burn back' from negative feedback. When you get a "1+1=3" answer, it triggers negative feedback. This burns back to the origin - the groupings and the data not fitting properly in sets. The result is a rewiring of the group, or the rejection of the data (in reality, a new filter to *omit* that data from consideration).
It isn't a unique thing - we experience it constantly. It's an important part of the mind... but we aren't often aware of it. Constructs can be extremely subtle. If you can afford something but chose not to get it, you soon find yourself believing that you never really wanted it (otherwise you would of gotten it!) If you could of hooked up with someone, but didn't, you didn't really want to. Coherency here is important, and it becomes more important the more you need to justify your actions. That is, the more you wanted something and the less you acted (without anything else to blame), the more you will rewire yourself. Using the same analogy, when you don't buy something, you get negative feedback along the "desire", rewiring it until you don't.
The subtle effect also happens when we start dealing with self identity. From this board, there is huge dissonance between identifying self-worth (deep down!) with intelligence, and the universal approach of intelligence as a metric for a peron's value. The first step in burning back is the moral stance - rejecting IQ tests, or the ability to measure intelligence in any meaningful way. It would be much harder to burn all the way back to self-identity (ie: it remains safe so long as we can reject quantifying it).
And I probably don't need to say anything about group identity. The kind of dissonance brought on that way, and the methods use to overcome it, is amazing. True for religion, social groups, companies, clubs... Same for Mensa as it is for Nation states.
What is feared here? What is trying to be avoided by the convolutions of thought?
The mind does not like losing coherency. The most common form of dissonance comes from groupings, such as "this religion is good, but my good friend quit", "my kid is good, but misbehaved", "nerds are like 'this' and this cool guy is into the same things".
The mind does not want to lose coherency, but when the logical structures break down, it ceases to be able to process until new paths are carved in.
It's like having a calculator put out the wrong answer, and so you take a hammer to it. The calculator would rather like you to stop doing that, and so it starts putting out the right answer.
Why is it hard to allow one's worldview to shift... or to embrace ambiguity?
Ambiguity isn't a problem. Ambiguity is a weak logical statement that is easily adaptable - if a concept is not solid, then it offers very little resistance to change. Worldview is just a phrase used to express coherency. To lose coherency is difficult and makes us non-functional and so we have resistance against losing coherency.
It is rather like saying "I don't know" as compared to "I was wrong".
It is also more/less difficult depending on the strength of existing structures, and the need to rationalize behaviour.
Who pays the expense of the unwillingness to change?
Different expenses for different people in different situation. Humans respect the unwillingness to change a lot, so there are many benefits to be non-adaptive. However, adaptability can also help you adjust to new situations - but not many of us are faced with consistently new situations in which benefits could emerge.
For example, in a tribe, everyone is good. Outsiders are bad. If you are placed in another tribe, you suddenly realize they are just like you. However, very few people will ever be in that situation. And it scales up too - nation states have the same effect.
A good example is also in religion. There is no particular loss by rejecting a friend because they changed groups. If anything, solidifying your belief in the group has more benefits than rejecting the strength of the group and keeping the friend.
On the other hand, harmful behavior can be protected by the unwillingness to change, but normally harmful behavior is not kept in check by dissonance.
Using MBTI stereotypes, the dissonance causing change doesn't have to be intuitive. NTs, for example, may be willing to reject an idea they have formed if challenged/perceived as not being 'rational' (assuming they have identified it). One example being the rejection of faith items (acceptance would cause dissonance, and it would be burned and blocked).
Do Eastern cultures have it easier than Western?
Dissonance, and its brothers denial and rationalization, are omni-present in Eastern cultures. Social conformity and all that lead to a shocking amount of beliefs and actions that are maintained through identification with them. I figure it comes from a more institutionalized hierarchy, but I have no idea.