WRB brings up a related point: That selective pressures (angling) can remove aggressive fish from populations. This is most intense when it's catch and kill fishing. C&R still has an impact, by aggressive individuals eventually being killed or damaged in repeated capture.
There's a good study on this highlighted on a great site run by Brian Waldman:
http://www.bigindianabass.com/big_indiana_bass/research/index.html
Scroll down to: Pressure and Bass Aggressiveness
But, although related in that it explains degraded fishing success over time, it's not the whole story, nor the question at hand: Whether bass can learn to avoid lures. They can. There are numerous examples but I'll offer this one: Keith Jones, Director of fish research at Berkley says that, in his tank experiments with lures on bass, he has to use a new group of bass for each test, because they learn so fast and stop biting. The question is; What is it they are reacting to? What part did they learn to avoid?
Which brings up RogerWaters neat question:
My thoughts, not research backed, is two-fold: That no bass will have enough bad experiences with crayfish to stop eating them altogether after being caught on them; They'll likely eat 100 or more successfully for every 1 they get caught by.
But beyond that, and what both gobig and WRB brought up, is that you can't separate the lure from the presentation complete: The
One of the best examples of this I've seen was a time I fished live nymphs on 2lb line to stream brookies on a public fishing stream. Now, I've been a dedicated, scholarly trout fly-fisher for years. I know my bugs and am a meticulous fly designer. It's amazing what people can come up with in terms of ultra-realistic flies. What I had driven home forcefully by those little brookies was that the fly, no matter how accurate an imitation, cannot be separated from the rest of the presentation.
What trout expect is for live insects to drift downstream with the current. The resulting image is FOOD. The response is, GULP! When I fished a live stonefly nymph down to those trout, the legs kicked, the body wriggled, the pale belly flashed; I couldn't have tied a better fly. But, if I didn't present correctly, if an errant current caught hold the line causing the slightest drag, the trout would reject the nymph. And interestingly, it wasn't that they spooked, they simply let it pass, like any piece of non-food like a pine needle, grass blade, or leaf bit. But, get it right and they eat the nymph, or a reasonable synthetic facsimile. The point is: The lure cannot be separated form the rest of the presentation elements, unless you are able to make it so.
Interestingly, if you ***** one of those trout with a hook, they'll sulk for a while, and can be more difficult to dupe afterwards. Contrast this with trout that have never seen an angler (high mountain streams here in Colorado) where I can be somewhat sloppier in my line control, and can literally ***** a trout 3 or 4 times before it's put off to a good presentation. Now head to a heavily fished C&R tailwater fishery and holy moly those are difficult fish to fool.
The take-home message is, the lure, no matter how accurate an imitation, cannot be separated from the rest of the presentation. And that individual fish do learn.
The saving grace is that conditions for bass vision are not always perfect and that aggressively feeding bass (especially in competition) are more willing to believe, for lack of better. But after being caught a number of times (or even once, according to some studies), bass become more circumspect.
So...How long can bass remember?
In one nifty study a group of bass were introduced to a Rapala minnow plug. They struck it readily for several minutes, then strikes fell off. The bass were divided into groups and tested after different time intervals, and the bass showed that they remembered something negative about the lure (indicated by greatly diminished hits) for as long as the study went for 3 months!
But, in our fishing, we have a certain amount of latitude in control in our presentations (within, of course, the considerable confines of having the lure attached to a d**n cord!). This is what presentation really is; It's attraction, then triggering. If you know how to control and adjust these, you may be able to continue to dupe fish on a given old lure. Presentation, all aspects of it, is in large part what separates the really good angler's from the average ones.
From my trout fly-fishing experiences, I'll offer an adjustment to the old adage, Presentation is 90% of catching, to this: After you've got presentation down, lures that fit the expectations of the fish, the one's that say FOOD! the best at that moment, will turn the most heads. From my bass fishing experiences, where food imitation is more difficult (because of the combination of still-water and the size of prey and lures), that triggering (how you manipulate any given lure) is critical to the amount of success you receive with any lure. And this factor increases in importance enormously as bass become educated.