disagreeOn clear water fish can be line shy
IMO fish can't associate line diameter any more than they can treble hooks. Proven long ago, fish eyesight underwater is as superior to an eagle's above water but unlike an eagle always on the lookout for prey, fish aren't capable of knowing or associating lures to anything remotely resembling prey.
agreeHeavy line also can kill the action of your lure
Lure action is
key when it comes to lure selection and presentation. Retrieve a lure the wrong way by imparting the wrong action or no action and fish won't react. Even the best lure designs can't provoke strikes unless lures move at the proper
speed and cadence (or non-cadence) that match a fish's sensitivity level at the time and place fish are be
suspended.
My experience has shown me that fish caught are mostly
inactive fish. The only fish that are actively aggressive are school fish and pre-spawners where the distance between fish is short and sensitivity high due to a
competitive irritability. The more irritable a fish is, the higher the chances of catching it and that's where lures come in by raising that level from zero to a level just high enough to
make a fish attack.
Years ago when I owned a cat, I would attach a string to a fuzzy object and move it slightly across the floor. At first the cat would just stare at it. But after a few minutes, the animal would become very aggressive - moving fast to trap the toy over and over, but after four minutes or so the cat would lose interest. A fish's
window of aggression is much shorter though and may strike a lure on another cast within less than a minute.
Anglers that concentrate on getting the color right, should be more concerned about getting everything else right about lure selection and presentation while keeping in mind that the simple reason angler's use lures is to make fish
react.