alt Hacker News> I'd execute a chord or a melody as if it were a word or a sentence, without thinking about syntax
This is exactly the same for me. The guitar fretboard is essentially synesthesia for me when I hear music. I hear a melody and part of my brain feels the shape of the fingerings as I go. It’s been like this for maybe 30 years or so (I started guitar at a really young age.)
I have no idea if this is common for guitar players though (I assume so? If you’re the sort of player that can play solos, you probably already “audiate” sounds via fingering) but it means I can basically always immediately play a song after hearing it once, even if it’s just the basic melody. I also have what I’d call “weak” perfect pitch (I can easily conjure an E in my head and then figure out from there what note I’m hearing via well-trained relative pitch) so often I can get the exact notes right the first time.
One of the reasons why I play a whole lot of jazz standards on different instruments is because it builds that feeling of just "knowing" (if I can hear the notes in my head) what I should play. I find "youtube jam tracks" wholly unhelpful, but I spend a whole lot of time playing to backing tracks for stuff like "All of Me" or "Sweet Sue" and playing the melody in different positions/ registers. I have been finding that a lot better for my playing than doing scales (though I still work scales on instruments where I in a learning phase).
But that feeling of "just knowing" is common among a lot of instruments and players.
I know that if I play some fingering on the clarinet, or jut grab a chord on the pedal steel, or whatever it's going to do what I intend without thinking about naming what I intend to do, just like i don't think about spelling, punctation, or letter position when I type (even though I often need to edit LOL).
So I agree- if I am playing bass with folks I will often just start playing without thinking too much about what notes I am playing beyond trying to decide on the general tonic key of the song.