Superstition
 

What prompted Men to adopt superstition in their lives, a trait not shared by Elves?

Could you clarify by giving some examples of what you see as 'superstition' among Men?

Is it because the elves actually *spoke* with the Valar face to face, and even those that didn't could meet with someone that did? Contrast that with men, most of which never spoke with the Valar (sans Tuor), nor knew of anyone living that did, or see any trace of them except hints and shadows.

And where there is an information vacuum, superstition rushes in.

But again, examples may make the discussion more specific. :)

Yes, let me show you where I begin this question from:

Christopher Tolkien - Unfinished Tales

JRR Tolkien - The Passing of the Grey Company

There is a clear distinction here in the fact Gandalf is associated with Elves by Men, which I believe is predicated by Mankind's inclination towards superstition and the rather simplistic views of the common man. This is a theme for Men which I suspect emanates from the Fall of the Edain as discussed in ATHRABETH FINROD AH ANDRETH. Suffice to say, (the second quote) in this instance it is Men who refer to Aragorn, Legolas and Gimli as 'Elvish Wight's' as they would be inclined to associate Elves (these 3, in their eyes) as strong warriors, undaunted by the ghosts of Men and undying in themselves. Elves as perceived by Men may be akin to the undead (undying, immortal), as Men would rarely have known them to die. I wonder then what the folk-tales of Men are regarding Elves and their seemingly everlasting lives. One thing that strikes me also, the remark itself seems simply ignorant of the company of 3. Aragorn, to those gathered might well appear as a Man however those who know nothing of the Rangers may well speculate Aragorn, in his strange garb and Elven tongue, is indeed Elven. Gimli is simply guilty by association as the Rohirrim seem to have had little dealings, if any with Dwarves. It is the Muster of Rohan and it would seem the Rohirrim would have little to do with Elves or Dwarves et al in their daily lives. Think of the context in which it is said and by whom, you can almost picture a man tending his horse, preparing to ride to battle and watching the 3 pass by towards Dunharrow and the Paths of The Dead. He looks down, shakes his head, carries on shoeing his horse muttering something about 'Elvish Wight's' to himself. This is why I love Tolkien.

Superstition almost always has some basis in fact. I would think the belief that Gandalf might be an Elf probably did have something to do with his observed associations with them, but was more strongly derived from the fact that he appeared to possess the Elvish immortality. If Men saw through their local histories and traditions that Gandalf was clearly much older than any Man should be, what other supposition could they reasonably make?

UT The Istari

Sounds to me a logical assumption for them.
The fear and awe of the Elves went far back into the First Age, so I don't see it as a matter of mere susperstition, but bourne of knowledge that the Firstborn were more powerful, and fundamentally different from Men and Dwarves.
Said Sador to Túrin of the Elves when the latter was a child:

UT Narn I Hîn Húrin

If that was the attitude among the First Age Edain, who saw and spoke with the Eldar daily, what could one expect from the likes of the Rohirrim, who had probably never even seen an Elf?