Learning a guitar tab: separating bass line from melody

Question

I've been playing guitar for a year now and I don't know much theory. I typically learn tabs, practice them, and finally (the climax) is to play while the song is playing.

The way I learn guitar tabs is fully merging the bass line with the melody. That means that if I have this tab:

 e----------------------------------------
 B------3-----3--------------0-----0----0-
 G----4-----4--------------0-----0----0---   (...)
 D--4-----0------0---0---------2----0-----
 A-------------4---0----2-----------------
 E----------------------------------------

             ("Keep it healthy" by "Warpaint")

I will see it as a whole and I will not care about the fact that there is in fact a bassline and a melody and both are two separable things. So, if I was learning this tab I would memorize that after playing with my thumb the 4th fret of the D string, I will have to play the 4th fret of the G string and the 3rd fret of the B string

Only after recording myself playing the song (just for fun) I started noticing that the bassline was almost "a song by itself" and the melody too. Like they were totally separable.

I recently got a MIDI piano keyboard and started learning a few songs. I noticed that I could learn the songs this way:

1. Learn left hand by itself (pretty easy)
2. Learn right hand by itself (pretty easy)
3. Play both hands at the same time (pretty hard!)

So, this "piano fact" and the "just-for-fun-recording-fact" have made me question myself if I should start separating the bassline from the melody in guitar tabs.

This is a more stronger and clear question under this scenario:
Yesterday I wanted to play a song but the tab didn't exist on Internet, so I decided to learn the song by ear. As for documentation I started writing in tab notation what I was finding out about the song (guitar part).

After a couple of hours, I had this:

   The thumb does this during the entire song:
   D ----2---0---2---0--------------------------
   A --0---2---3---2----------------------------
   E -------------------------------------------

   Other 3 fingers do this:
   e --------------------------------3--0h1p0-0----
   B --0h1-3--0h1-0h1-3---0h1-0h1p0----------------
   G ----------------------------------------------

   e --------------------------------0-0------------------
   B --0h1-3--0h1-0h1-3---0h1-0h1p0------3--0h1-0h1-0h1---
   G -----------------------------------------------------

Here comes the question:
From my experience in learning tabs, I know that if I merge the above thing into one integral tab, I could learn it as a whole. A fully merged thing. And after practicing a while and playing fluently, the bassline will arise byitself, magically.

Should I learn this like that? (merging into "an integral tab") or should I learn this as I learn things in the piano?

Its kind of sad that if I learn it mechanically (by merging) I will reach faster to the "climax", which is enjoying the song by playing fluently.

sidenote.
This is the song: www.youtube.com/watch?v=Z_XAMeEu_FQ

Edit:
Instead of "bassline" and "melody", we could call it: "thumb-part" and "other-3-fingers-part". If its more correct theoretically

Answer 1

I gather that we are talking about practicing. I think it is good that you notice these issues. There is another (related) can of worms to bring up, that sometimes it is good to separate your left hand and right hand practice on the guitar, depending on what you are trying to achieve....

Experience guides guitarists to recognize tricks that often aid the performance of a particular segment of music (use of open strings in a particular way, use of tapping, or sliding up and down the frets versus changing the fingering, for a few examples). Sometimes the separation of parts is useful, but often it is not compatible with these tricks.

Your suggestion to separate the parts may often be useful in figuring out music by ear. But in performance and practice, usually the whole thing is combined in one thought process for the guitarist. It's a left hand right hand/ left brain right brain thing (http://en.wikipedia.org/wiki/Lateralization_of_brain_function#Movement_and_sensation) that you take advantage of on the piano, and is distributed differently on the guitar.

That brings us back to this: Sometimes it is good to separate your left hand and right hand practice on the guitar. Sometimes when one or both hands have something difficult to do, you can improve your ability on the whole thing by focusing on one hand at a time, or just the hand with the difficult part. (As long as you also combine hands for some of your practice session.)

note @tim 's comment is an important one so I add it here to emphasize it. This technique that I am suggesting as an alternative is useless without combining it with and comparing it to with more standard practice where you work on and listen to both hands at once.

Answer 2

It's more complex than just a melody and bass line - obviously a melody line exists whenever there is a vocal but the music could also be considered as a sequence of chords or as a bass plus multiple lines if you are playing multiple notes at once.

The actual "bass line" isn't even shown on a guitar tab; you're only seeing what the guitar part for that song is. There would normally be a whole separate bass part for the bass player so you're really playing in the mid-range and trying NOT to impinge on the bass.

For guitar playing, I think recognising the chords the tab is based around (it nearly always is) is more useful. But it depends a lot on the song - is it a singer-songwriter-just-a-guitar song which is mostly chords with a few twiddles, or the guitar part in a full band where 2/3 of the music isn't played by you anyway?