Psychophysics by definition is a branch of psychology, but that Wikipedia defines psycho-acoustics as psychophysics does not a mean that most define psycho-acoustics as psychology. As stated, most of the people I know in the field do not see themselves as anything related to psychology.
Since we are on Wikipedia,
My experience is that psychology rarely, if ever plays into the professional aspects of psychoacoustics, with the exception of environmental controls, and on here when we talk about "subjective" audiophiles, and again borrowing from Wikipedia,
W.R.T. environmental controls, as is pertains to venues, psychology does play a significant part. There is a direct correlation between the comfort of your seat and your perception of the quality of a performance. A rumble in your seat at the theatre makes you go "wow amazing sound" even though overall it may be meh!