Regarding the eyes, KB's point is valid. People sometimes turn their eyes before they move their heads. Something that is actually more common is that people blink as they turn their heads. It's sort of like a built in camera cut for a scene change. Without the blink, everything is a blur, and it takes a brief moment for the eyes to readjust to their new positions. Observe people and watch their eyes as they talk and look around. They usually blink as they turn their heads.