Logically speaking, lack of knowledge, or simply put, "not knowing" is a debilitating factor in learning. So, how can “not knowing” help a vocalist advance?
Knowledge can inhibit learning when preoccupation with knowing supersedes the implementation of action. The knowledge of action, therefore, or "body knowledge", becomes a paramount consideration. Rather than replace conscious knowledge, however, why not find ways to integrate the two?
This is not to say that repetition and imitation are unimportant. Learning depends upon establishing targets, and repeatedly executing tasks with clear assessment. Those same down linemen spend the majority of their time reacting to the physical stimuli that they will encounter in the game, as vocalists must spend the majority of their time habituating the reactions they rely on from their voice.