It's quite possible that the situation is different in academia, but in my line of work I tend to find the opposite: some of the most accomplished people are very cautious and unwilling to take strong positions without thinking them over. Usually, because they are so knowledgeable and thoughtful that they can, as soon as they start saying anything, see a million possible caveats. In the worst case that can be paralyzing, but it can also help avoid the opposite behavior: the hot-headed, confident, untimid person who just doesn't really know enough (or think over what they know) to realize why they should be more cautious about overarching claims, especially on questions that a lot of smart people have looked into already.

It's not a universal correlation, but I've generally noticed junior and less knowledgeable people (graduate students, early-career professors, etc.) to be much more brash, confident, and even aggressive in that sense than accomplished researchers, though there is a bit of an inverted-U curve (undergraduates and 1st-year graduate students tend to be very timid). Of the people I've met professionally, probably the most humble, and least willing to make strong statements without thinking them over and later offering a tentative opinion with caveats, was Bob Moog, who is also probably the smartest and most accomplished person I've met professionally.

I agree with your assessment, and I think in many ways one of the critical parts to learn is how to assess when it is ok to "turn off" the critical eye and be brash and confident and aggressive.

Some of my most valuable experiences stemmed from just throwing myself in on the deep end instead of waiting to analyze all the implications. But at the same time those experiences were terribly _hard_, and carried a great deal of risk. E.g. my first company was an ISP. Started it with some friends at 19. Knew nothing about running a business or about setting up a large scale WAN, or about accounting, or sales, or configuring Linux servers. A year later I'd had hard, brutal and effective lessons in all of that and more.

If I'd spent time carefully trying to figure out the risks and implications beforehand, I doubt I'd have started that company. It didn't make me wealthy, but it was definitively worth it in terms of what I learned, and the connections I made also led directly to my next job and overall it has been pretty vital to my career.

On the other hand, there are many situations where not stepping back and being careful and considered and chasing down the implications up-front would've had disastrous consequences.

The problem isn't being cautious, if you know when not to be, but not taking action. Being cautious because you want to chase down and understand the implications is very different from being timid about addressing weaknesses in your knowledge. Whether you address those weaknesses with research or by trying is less important than avoiding paralysis.

"People who are timid are less willing to attack schleps, to acknowledge schleps and ask for help with schleps. Maybe this is the correlation? Maybe people are timid because they are embarrassed or unconfident in their ability to overcome schleps? Maybe they put up a wall or get defensive so that others who seem smart (and who blow through schleps) don't see them as unintelligent."

Very useful insight. As someone who isn't timid at all, I think often times I may help in my own way build the wall for timid people.

I am so caught up in shooting down "schleps" that I think that ends up being even more intimidating.

And I think the counter for that is as you say, being "Extremely welcoming and nice."

Because it's always better to take "schleps" with someone who is making you feel better about it than someone that is just doing the work, and moving on with no consideration for their feelings.