It's nice to know that research backs up what I expected based on introspection.

In my experience, when I'm in problem-solving mode, language isn't involved in generating ideas. Ideas that could take several paragraphs to elaborate spring to my attention seemingly fully formed, much faster than I can consciously process language.

But if I'm working on a hard problem, most of my ideas about how to solve it will be wrong. The flaws are not obvious until I can write down my thinking process and point to where the mistakes are.