I'm a post-bacc student researcher, a teacher, and I do project management, working toward a career in biomedical research.
It's hard to translate a general problem into a concrete understanding of specific technical issues and solutions for them. I find it hard to stay curious, and to continue work, when I lose sight of what new insight the project I'm working on is going to reveal. Not only that, but if I catch a whiff that my project is either overbuilt or underbuilt, it can kill my motivation before I have even fully clarified that to myself.
I was interested in a heavily-cited study in the field of education, which graded education department dissertation reviews for the quality of their content and found low scores. They've since used this as justification for overhauling their program to focus more on scholarship. But they never actually checked to see whether dissertation lit reviews are correlated with career outcomes, or did any kind of published experiment.
I wanted to look for such a correlation with career outcomes, and I was interested in STEM research. Up to this point, I was riding on pure curiosity, and found it easy to read, write, and stay engaged.
At first, I was going to copy the authors by grading 30 biochem dissertations from around the year 2000 for the quality of their lit review, then supplement this grading by correlating the grades with the h-index of the authors 20 years later. This would have taken a lot of work. It was a major divergence from the original study. And I found it difficult to start.
Then I hit on the idea of a much simpler study, simply checking whether there was a difference in total publication count (easier to measure) among authors whose STEM dissertations contained a stand-alone lit review vs. those who did a purely empirical lit review. This required no grading. And, I realized that of course I would want to know this before I committed to the larger project.
It took me an hour or two to gather the data and plot it, and I found no correlation. Right then and there, I realized that my prior on the genuine causal importance of the content of a literature review on long-term career impact, especially in STEM, was so low that this data tipped me over into "why bother" territory.
And that was great, because I was doing all this as part of a larger research project to identify was to help undergraduates become better STEM researchers - very meta, I know. I have lots of other avenues to investigate. So getting no result in my exploratory data allowed me to abandon that line of inquiry for others that might be more fruitful.
If I'd gone through with the full analysis, I'd have used up so much time and energy, only to arrive at a result that would still just have been a non-experimental observation, and not very reliable at that, that who knows what I'd have done? Maybe I'd have tried to act as if finding a correlation there was important.
I think this is why curiosity really is a consistently important motivator, not just a way to get started. If you are always keeping your primary research objective in mind - in my case, how to help undergrad STEM students become better researchers - then being guided by a sense of curiosity about that central question will help you prioritize your sub-projects.
If you're driven by pure "grit" to keep going on a specific sub-project even when you've lost your curiosity, then maybe that's a sign that you no longer believe the work you're doing is going to teach you enough to justify the cost of investigation. I conjecture that "grit" might be associated with sunk-cost-fallacy reasoning.
I think the idea of curiosity being a transient sensation akin to emotion or hunger is not accurate, or at least not what I mean when I use the term in an intellectual sense. Nor is it distractability, the desire to jump down every rabbit hole that presents itself. Instead, it's about having goals that stem from a sense of value and importance, which remain fundamentally steady even as you update the specifics over time.
It's the intellectual equivalent to having a house half-built.