Oh, Frank -- there you go again ..... you seem to really have a knack for over-reduction.
You keep trotting out and hanging your hat on these various studies and theories, but fail to take in to account confounding variables.
In your little candy bar study, people are deciding between options that are all, presumably, aimed at the exact same goal -- snack satisfaction (oh, and
do not try to break down "snack satisfaction" in to finer granularity -- that would just be silly and fallacious). Trying to draw definitive conclusions from that would be premature (and if I remember correctly, I think the study itself may have even made a nod to that). Never mind that decisive vs. indecisive is as much about personality as anything else. So, what -- you're now trying to either eliminate or engineer
personality with your rule set? Just take the human factor out completely?
Oh, and don't let me forget about the issue of the nature of various goal-oriented behavior. In your little candy bar study, the "goal" is very nebulous. In a RPG setting, goals (at least as we're talking about here) are much more discrete and defined -- which necessarily at least give you a better framework for decision making.
Now you want to trot out Dunning-Kruger? Please.
Yes, it is empirical fact that people often have an over-developed sense of their own competence -- that's just a simple matter of their ego getting in the way .... and probably can be linked, at least in part, to this asinine practice of giving trophies to last-place finishers (it's been happening for decades, and it makes me want to vomit).
The confounding factors here are all related to the
specific social dynamics that are (at least, in
my experience) inherent in this type of gaming (that being the emphasis on team work and mutually-interdependent goals). It's because of that dynamic that, over time, one's
actual competence will naturally increase (well, if anyone really cares about such a thing). I see it all the time -- someone has their character that they think is awesome; then someone else takes the same concept and amps it up to 11. person "a" sees this and is like "how the hell are you doing that better than me"; person "b" explains through instruction and demonstration; person "a" then gets better. The flip side of that (i.e., the under-confident, over-competent person) presents itself as someone who is reticent about "just doing it" ... this is a function of someone actually knowing what they don't know, and letting that get in the way. Again, I've seen it time and time again -- proper encouragement and so forth goes a long way to helping to bring someone out. It's a function of a dynamic social setting.
Let's look at your examples --
In the case of grandma's driving -- this is just an example of someone that assumes that the length of time of experience is all that matters (without ever having actual data put in front of them for honest consideration). This is someone who has been allowed to get
way too set in their ways.
In the case of the under-confident engineers ... they have seen their betters in action (often in an environment that excludes certain context), and have set themselves an unrealistic and overly-idealistic standard of achievement. These people are typically going to be sharing a table with those who are lower on the competency scale than them .... and this builds confidence.
Now, if you're sitting in an echo-chamber, then no, nothing is going to change -- and that's a failing of the group. However, on the flip side -- if you have someone who has some "issues" at the table, and you are indeed recognizing those "issues", then it is incumbent upon you to address those issues. So, Dunning-Kruger doesn't really apply so much is you're actually giving/getting real-time, empirical, and useful feed-back.
Bottom line -- your little studies and theories are completely irrelevant, unless you're also willing to discuss confounding factors which happen to weaken the presence of said studies/theories.
