For many years I have had an interest in the psychology of music. I used to think that the psychology of music really involved the processing and creation of sound as a sensory/motor process. More recently, I realized that Human Factors (ergonomics) are also a critical aspect of the psychology of music. The sources below address both issues.

• Information about ergonomics, and anatomy of the hand for physical therapists and musicians.
  
• Excellent powerpoint slide show on the ergonomics of piano playing including ways to maximize quality of performance.
  

The Psychology of Music as a sensorimotor/cognitive process

• Scholarly article by Robert Gjerdingen on the history of the psychology of music.