I’ve been told I have absolute pitch. I play music by ear. I don’t know if it’s true or not though. I think I have a reference note – an E – that’s always ‘there’ based on a song I composed as a child that I still play.
I don’t know if I always use it but it’s always there in my head at a greater amount than other notes.
I’ve been studying neural entrainment, “Dynamic Attending Theory”.
Primarily to do with finger tapping matching between external and internal or internal and internal, but also applies to pitch because Fourier transforms (or gammatone filterbank).
No idea if it will ultimately relate to absolute or relative pitch perception but I suspect it will and that there’s probalby studies related if I looked.