Author Diane Ackerman was on a book tour promoting "An Alchemy of Mind: The Marvel and Mystery of the Brain" when her husband, Paul West, suffered a massive stroke that radically combusted the alchemy in his own brain.
There is a reason that an autistic person rocks, spins or flaps. The problem is that we don't know the reason. So we work to change the external behavior and assume that by doing so, we've changed the internal state. But we can't know for sure.