Performance practice draws on many of the tools of historical musicology to answer the specific question of how music was performed in various places at various times in the past. Although previously confined to early music, recent research in performance practice has embraced questions such as how the early history of recording affected the use of vibrato in classical music, or instruments in Klezmer. Within the rubric of musicology, performance practice tends to emphasize the collection and synthesis of evidence about how music should be performed. The important other side, learning how to sing authentically or perform a historical instrument is usually part of conservatory or other performance training. However, many top researchers in performance practice are also excellent musicians. Music performance research (or music performance science) is strongly associated with music psychology. It aims to document and explain the psychological, physiological, sociological and cultural details of how music is actually performed (rather than how it should be performed). The approach to research tends to be systematic and empirical, and to involve the collection and analysis of both quantitative and qualitative data. The findings of music performance research can often be applied in music education.