Related to this whole discussion, and something I think I must have brought up before on here because it has been kind of a running line of interest for me over the years, are the two philosophies relating to “mixing it up”. One of these is the “consistency” view, for lack of a better term, and is something that was expressed in Dec Hogan’s book where he gave some visual confirmation - namely the view that fish will often see your fly several swings before it comes close enough for them to actually respond, and that the fish do not like it if the presentation changes from one swing to the next and will get scared off the take. I’ve head Dec and other members of this school of though say things like the best presentation is one that “looks vulnerable.”
The other view which I guess we could call the “change constantly” theory is that the more presentations you show the fish the more likely one of them will elicit a reaction at that time and place, in the absence of any prior knowledge in a particular spot. Some experienced people advocate changing the presentation from swing to swing unless you have determined one thing to be working. One of my favorite guides will, for example, invariably point out to me if I do 3 or more swings in a row without changing up the presentation!
This view is, if not related to, then somewhat in accord with the idea that the state of mind of the fish when it grabs a fly is not always attraction, but anger or anxiety when it goes for the fly. Maybe you could describe this as the fish “feels vulnerable” situation. Of course it is a small step from there to the fish getting the hell out of dodge. But there is an often recorded phenomenon where a fish has been observed to sit on a lie for a long time with total indifference to any fly and any presentation, but when driven off the lie briefly or otherwise disturbed such as when a boat drives over it, will suddenly “wake up” and go after a fly and presentation it had already passed on many times. The idea there is that when the fish is in a very relaxed state it may be indifferent, but if something agitates it if may tend to reorient to a more combative stance in relation to its environment for a certain time.
I can’t say I have strong evidence one way or the other. I personally feel like I have had more success on slow days where I have been working very hard trying everything, but the numbers are not high enough to really tell, especially given the conditions change from day to day. Plus I may be remembering those days more due to the illusion I had something to do with the results. On days where I choose to be consistent I suppose I’d be more likely to just chalk things up to luck.
So which do people follow most often, consistency or constant change? I feel like all activities with low probability success rates are highly susceptible to domination by superstition or custom as opposed to anything that might resemble actual hard-core “Knowledge”.