Neutrality can be postulated as a biological,
pre-social condition exhibiting an absence of emotion, expectation,
conflict or story. This does not mean to be dead, or passive, but
rather to be available, disponible.
It is typified by pure denotative physical action, with every cell in
the body in agreement. Unmasked, it is about economy of effort and
simplicity of action. Masked, it is also about style and amplification to the level of the mask. It is a condition for which to strive, not a state one can ultimately attain.
Being non-dramatic, it is primarily useful for training, not public performance. (However it could be useful for a minor role that has to accomplish an activity upstage without drawing focus from the primary scene downstage!)
I emphasize to my students that the performer’s success at achieving neutrality is only relative to the powers of observation and interpretation of the people watching.