Not long after I started on guitar, a friend and I talked about slapping together some kind of group, so we walked to a nearby discount store- he bought an electric guitar and I bought a bass. That went nowhere, they moved a few years later and nobody else in my age played much of anything, other than Brian (in the link) and he had been bumped three grades ahead as soon as they moved into the neighborhood, so he was playing with the older guys. Later, I had bought a bass with a bad neck from a friend who had been in a Fusion band, but it was good enough to bang around on. Eventually, it basically became unplayable but eventually, I was lucky enough to find a replacement neck and while I was getting that set up, I became impatient and bought another bass to play. I watched some video lessons on YouTube and having discussed playing bass with some others, I really started thinking very differently from when I played guitar- a lot of the time, I was almost on cruise control because I was familiar with the fretboard and could do it without thinking. Not that what I played was great, but with my ear, I'm able to get around without annoying anyone too much but that also led to a bit of boredom, on guitar.
On bass, there's a kind of mantra- "Where's the one?", meaning "Where's the tonic?"- this is more important for a bass player than anyone else since they determine the key. In addition, I really started to think about where the 4,5, 7 and 9, are, too- the octave is easy, but the others are different, especially when a bass runs out of strings before a guitar does.
Playing bass again made my thinking change significantly when I played and before I bought the second bass, I had noticed that when I listened to music, I wasn't thinking about or listening to the melody as much as the bass lines. Playing in a different range, playing the counterpoint has really helped.
