There exists a so-called "Eureka" moment, or euphoria from solving some hard problem. There are also people who like solving problems. From what I know, this is caused by release of dopamine, triggered by the fact that problem is resolved.
However is it true that humans in general do have this behavior? Is this behavior found in children consistently? Is it possible that with age people loose ability to get large dopamine release after solving "hard problem"? Are there people who do feel "pain" instead?
(In my definition, "hard problem" is a problem, which requires causal inferences across many mental objects in domain that the person "knows" good)