In what became 5th most-read new post on LessWrong in 2012, Morendil told us about a study widely cited in its field... except that source cited, which isn't online and is really difficult to get, makes a different claim — and turns out to not even be the original research, but a PowerPoint presentation given ten years after the original study was published!
Fortunately, the original study turns out to be freely available online, for all to read; Morendil's post has a link. The post also tells us the author and the year of publication. But that's all: Morendil didn't provide a list of references; he showed how the presentation is usually cited, but didn't give a full citation for the original study.
The link is broken now. The Wayback machine doesn't have a copy. The address doesn't give hints about the study's title. I haven't been able to find anything on Google Scholar with author, year, and likely keywords.
I rest my case.
Person B saying "there is a solution" provides person A with useful information.
Little details, such as the speed at which another person finds the solution (and the fact that they found it at all) gives clues as to what type of problem it is - divergent or convergent thinking, overall hardness, etc.
The fact that a specific person x was able to find the solution narrows the space to "things that person x would be good at solving".
Finally, the resources which another person put into finding the solution provide a rough upper bound to how many resources the seeker will have to devote to find it for himself, reducing the risk involved in the investment.
All of these effects are social in nature, which means that it is not unlikely that we humans have in-built mechanisms to use this information without being able to consciously articulate what exactly the information we have gained is.
That someone found the solution cannot be relevant in cases where it's known that there is a solution, where this effect seems to still apply. I don't see how one could extract anything about divergent or convergent thinking, since you don't know how they solved it or usually how long they took; if you knew how long it took and you knew whether they tended towards convergent thinking, then you could infer whether you should focus harder on convergent or divergent thinking, but if you know neither...?