Final answer:
The claim that everyone progresses through Fitts and Posner's stages of learning at the same pace is false, as individual progression can vary widely.
Step-by-step explanation:
The statement that Fitts and Posner claimed everyone moved through the stages of learning at the same pace is false. While it is true that stage theories like those proposed by Fitts and Posner suggest a universal sequence of development, individual progression through these stages can vary significantly. Fitts and Posner's theory specifically addresses the phases of motor skill learning, articulating that individuals go through distinct stages as they learn and refine motor tasks. These stages are the cognitive stage, where the learner is trying to understand the task; the associative stage, where the learner begins to refine the skill, and the autonomous stage, where the task becomes automatic. However, the pace at which individuals move through these stages can be influenced by a variety of factors, including prior experience, ability, and learning environment.
Regarding the muscle fiber question, the proportion of slow-twitch to fast-twitch muscle fibers is not uniform across all people. This proportion can be influenced by genetics, training, and the type of physical activities an individual predominantly engages in.