For autistics, sensory sensitivities often dictate the development of particular behaviors. Stimming refers to movements—such as flapping the hands or tapping the fingers—that help relieve anxiety that comes with overstimulation. It can also take the form of mental stimming, such as repeating numbers, words, or letters (also referred to as echolalia). When I was a child, for instance, I had a mental count of the electrical poles on my street, and every time we drove by, I had to mark in my mind the midpoint between each pole.
