The initial post is reminiscent of a variety of points made by Bill James in his book "Catching Trout in Australia" that I believe is a very respected text, or at least it was when I bought it many years ago. Amongst other things, he says:
"Trout locate their food through the use of sight, smell and hearing but the final attack on prey is accomplished through use of vision" (p.55)
"So keen is a trout's perception through this sense and so superior is it to the miserable olfactory functions of humans that its sensitivity must be inconceivable to man" (p.60), on the trout's sense of smell.
"Anadromous fish, such as sea-running salmon and trout, swim hundreds or even thousands of kilometres to find their way back to the stream of their birth by tracing odours that are unique to that stream. Salmon have been known to pause in their spawning run because of the smell of bears that had drifted downstream to them in the current. On other occasions, salmon have been deterred by the smell of man that permeated the water merely through the rinsing of hands" (p.60), on the salmonoid sense of smell, and observations of salmon.
"Trout have been known to refuse artificials that are tainted by human hands and yet accept the same artificials after they had been doused in spittle. Strange as it might seem, human spittle proved to be the third taste preference, after worm and liver, when tested on catfish" (p.60)
"Experiments with Chinook salmon disclosed that they were able to detect seal and sea-lion extracts at dilutions of one part in eighty billion" (p.60)
"There is no doubt that it is very often a fish's sense of smell and sense of hearing that draws it to the location of food which then enables it to target the food visually" (p.60)
Of the sense of taste, James suggests that as with humans smell and taste are closely linked, however "taste relies on contact or close proximity".
I also recall reading somewhere in James' book or perhaps another that the scent of a human may be 'rinsed off' after two or three casts, however I don't recall whether that was specific to bait, artificials, or both.
In an interesting sidenote within the book somewhere James also notes that anthropomorphism of a trout's behaviour (likening it to a human's) - particularly its ability to reason - is a mistake, and as such suggests that if it smells right, tastes right, looks right, feels right, and the trout is hungry, it will eat it. James' emphasis on smell however, is so profound that I am often convinced that it is of the greatest importance to anglers bar none. I then have to remind myself that fish are regularly caught on artificials that even without a human scent are unlikely to smell like the real thing (plastic vs a minnow, fur vs an insect). It would then have to be assumed that in the presence of a hatch or other food rich event, either:
1. the scent of all the other insects are able to suitably disguise that of the artificial.
2. the movement of the water is such that smell becomes unreliable with many smells mixing or turbulence disturbing scent direction, and therefore in clearer water with reasonable light vision must be relied upon more readily until a morsel can be tasted or felt.
Situations like these would account for the ability of an angler to catch fish on artificials in food rich or fast waters, however wouldn't explain the ability to successfully fish artificials in lakes.
It may require a more thorough study of the book to properly discern James' ranking of the importance of the trout's senses, however I hope I have provided at least a few points that one can ponder.
Those are my two cents anyway,