It can be dormant in adults. I discovered it when I was 16 after meeting a pianist who had it and “taught me” how to do it. I kept getting faster and more accurate as I practiced solfeggio in music school in my 20s.
Crazy thing is it changes with age. At around 30 I started regressing. These days I identify the tones but shifted by one semitone.
Crazy thing is it changes with age. At around 30 I started regressing. These days I identify the tones but shifted by one semitone.