Should it be the goal to memorize a basslins so you don't have to ever look at the notation once you've got it down? I have a bassline down cold but I mess up when I go back to reading the notation. Thanks in advance for your comments.
Straight answer no.
Remembering what you have played is just the internalising of the music.
As you have found out because you have learned it you have stopped reading that songs notation, so you mess up. This is why you have to continue to learn to read, and by that I mean actually read and associate the notes to playing.....not let yourself go through the motions.
If the song becomes memorised then fair enough, but do not sit and try and memorise it.
This is two seperate tasks, learning is a Frontal/Parietal lobe task where as the remembering it for the long term is an internalised task from the frontal/parietal lobe via the Hippocampus. It is not fully understood how the relationships work, but it can be liked to that once you learn a task in the frontal/parietal area it is stored for recall via the Hippocampus.
Similar in the way a computer works using RAM.
Your reading skills are there to recognise notes and play them, not to recognise and remember. As you have found out if you assume you know a song it is hard to read it and play it from sheets, your assumption over rides the need to read because it assumes you already know it. When you read it again you have two areas fighting for control of the process, you tend to skip through it using it for reference to remind you rather than for you to follow. This is how cheat sheets works, or chord charts, or notes etc. they remind you of enough to make the internalisation come to the fore and perform.
The great thing about reading skills is you do not have to learn anything other than reading, you do not need to remember, understand, or even like what you are reading, you just read and play it.
So a word of warning, pay attention to reading, and i mean reading what is on the page, not assuming what is on the page.
Your reading skills are developed because you have no real need to learn and remember the music, it is remembered to you by the fact it is written down. So it is when a task is learned, you do not need to follow the instructions so to speak.
But if a certain piece or song has been re-arranged say, then you tend to miss the nuances of the new arrangement in favour of what you know, because you are using what you already know, rather than what you should be learning.....you read into it things that are not there, it's like you fail to see it, untill it is brought to your attention, then you start to read again.
But this process of assumption and reading goes on, but the more it is done the better the player becomes at using it, i.e. reading for the sake of reading, not learning or remembering as the task.
Like I said you will internalise, you cannot stop from doing it as much as you can fail to recognise a face you see everyday, or if you met a person with your parents name, their image or memory of them races through your mind, the trick is like I said remember to read what is actually on the page, not what you believe to be on the page.
So to this end I would say if a song becomes learned to memory then treat it with caution and you can remember it different? Sometimes you cannot remember it at all to even explain it, but you can play it through. This is because once you start playing it, you are reminded of what comes next rather than any individual part.
Such as what comes after L in the alphabet?
Reading music means you do not have to learn it, but if it happens you still have to read.