A central aim of the conductor should be to look like the music.
If he is merely beating time—with gestures not in keeping with the style—he may be conducting beginners in very simplistic music, or he may be worried that the sense of pulse may evaporate within the ensemble, or perhaps he is irritated, or he may simply not be very skilled.
On the other hand, if the conductor’s nonverbal communication is well centered in the specific music being conducted, even complex or unusual gestures can have an air of ease. Being “in the music,” imitating its essential nature, leads to a genuine flow of communication that in turn evokes the desired sonic result.
How will a conductor know whether he “looks like the music”? He can look in a mirror, but his nonverbals might in that case be affected/altered by self-consciousness. Video recordings are invaluable aids in studying oneself in this regard. Another, differently objective reflection will be seen and heard in the human beings he is conducting. For instance, do questions, comments, and other feedback indicate that the musicians, aided by the conductor’s nonverbals, “get” the music? Over and above any dialogue that arises in rehearsal, the “proof in the pudding” is whether the music turns out to be stylistically authentic, manifesting appropriate interpretation.
A conductor should clearly be in tempo (which is a universally understood concept) and in style (which is not as universally evidenced in aggregate practice). If he is in tempo and in style, he may be said to be in the music. This embedding of oneself in the music turns out to be a strong reflection of the composer’s intentions. There is evidence, then, that the conductor has studied what is written in the score—understanding what it “looks like”—and is intentionally pursuing its essence.
Those who hear and don’t act are like those who glance in the mirror, walk away, and two minutes later have no idea who they are, what they look like.
– James 1:23-24