...tend to assume other people think in an identical manner to themselves.
I don't. I know for a fact that I think in a manner radically different from most others. I know this just from trying to explain things; I use words in a manner which is... absurdly poetic. I can stuff as much meaning in a sentence as would take some people several pages. It's just typically difficult if not impossible for other people to decrypt everything I've put there.
Not to say by that that I am smarter than other people, although that is true, but that I think in the same manner. The word "externality" from a couple of posts back, for example. When I use it, the two definitions aren't distinct; I know they aren't distinct, one follows from the other. So saying that information is missing from the system results in externalities is a very simple logic. Other people might find that I was missing a step in the logical process, however, because I didn't demonstrate this; an externality IS missing information, however. The statement is by my thought processes a tautology, necessary to state only because other people do not integrate information in the same manner I do.
And this is the manner in which I think. As a result, or perhaps a precursor - the causality is unclear to me - I integrate information at an absurd rate. There's almost nothing I know which isn't implicitly or explicitly related to other information; integrating information is largely the process for me of explicitly identifying these connections so they can be used implicitly. Thermodynamics was absurdly easy to me after Physics I, which, introducing a lot of concepts I hadn't previously integrated (particularly concerning rotation), was the most difficult course I've ever taken. I didn't merely integrate the specific information Physics conveyed, but the model, the metainformation; Thermodynamics contained very little new information for me, because it's operating on the same model, the same metainformation.
And I know for a fact that other people don't think the same way I do. Mine is a slow and ponderous thinking process, powerful only because of the level of meaning encoded in each concept. I know somebody for whom thinking is a delegatory multi-track process with a stack trace at the end of each thread's conclusion. His thought process is radically different from mine; we still tend to arrive at the same conclusions. An observer might conclude our thought processes were identical; this is far from the case.
The key point about an effective thought process is that it will, by and large, arrive at likely conclusions, given supporting evidence. My thought process excels at certain tasks; his excels at others. The intersection of these two thought processes is pretty substantial, however.
I know little to nothing of professional psychologists, but have considerably more experience with hobby psychologists, and they tend towards comprehensive models. They want to define how the brain works, assuming, on the basis that people frequently arrive at similar conclusions, that there is one cohesive model that can describe this process.
This assumption is fatally flawed, however; it presumes that given a set of inputs, and given a single output, only one process can get from A to B. The inputs and the outputs are just data points, and for any finite set of data points, there are an infinite number of potential formulae that can describe the graph.
Similarly, there are an infinite number of possible ways for somebody to be smart.
Some insist that this is unrealistic; that our brain shares a common architecture, that it must share a common data model, a common algorithm. It is this insistence which is unrealistic; it presumes our logical faculties are hardcoded, something for which there is little to no affirmative evidence, and quite a bit of contradicting evidence. Feral children are a frequent example, but also studies into linguistics as a formative brain model, demonstrating for example that cultures with more words for colors are better at distinguishing between colors.
There may be evidence I haven't seen, this is always a possibility, but my personal experience AND every piece of substantive evidence I have seen suggests very strongly that there is more than one mental model, that the pursuit of a universal model for the mind is fundamentally flawed in its base presumption that there is a universal model to be found.
This, I think, is a fault Ayn Rand was pretty heavily invested in, and one of my divergences from her mode of thinking. I have encountered people who are willing to admit hypocrisy, and more defend it as a necessary element of existence; contradiction is something permissible not merely in their model of the world, but their model of themselves. Contradiction isn't merely impermissible to me on a moral basis, it breaks the very mode by which I think, by which I reason. Integration is -how- I think. Contradiction throws null pointer exceptions all over the place; it just plain doesn't compute. I could as easily invisage ultraviolet as a fourth color as imagine a persisted contradiction in my thoughts. (That's not to say temporal contradictions don't arise, but they can't be integrated while contradicting; either the old or the new contradicted information has to go. I am literally incapable of holding onto both at the same time.)
So I know there are multiple architectures for the thought process, simply by virtue of the fact that mine is extraordinarily and obviously divergent. Insistence to the contrary is just silly to me.