I don’t understand how people can animate heads in local (parent) space. Here is a great example on why you want to animate the head in world space rather than local space.

Our vestibular system acts as a gyroscope allowing us to keep our head’s direction independent from the rest of the body.

Using local space for the head also requires so much counter animation work, hindering granular refinement of the motion.

The motion of the body is so complex and requires a lot of finessing when the head seems so still. In production you want to have the freedom to add more layers of complexity in the body without having to counter animate the head.

https://www.facebook.com/WWFFrance/videos/329660194537260/

Related posts:

World orient head and shoulders

Local eyes vs World eyes

So you want to be a rigger huhh? version 02