There is a slang word that people in the autism community use to describe the noises and movements they sometimes make to feel calmer. It also covers habits such as nail-biting.
What is this word?
It's stimming, short for the medical term self-stimulatory behaviours - a real mouthful.
Stimming might be rocking, head banging, repeatedly feeling textures or squealing. You'll probably have seen this in people with Autism Spectrum Disorder (ASD) but not really wanted to ask about it.
It is a term used widely in the ASD community.
Why do people with autism stim?
There are many reasons. The world-renowned animal behaviourist Temple Grandin is on the spectrum and says most people stim simply because it feels good.
In Autism Digest in 2011, she said dribbling sand through her fingers was a feeling that used to calm her. Referring to her own childhood experiences, she said that stimming "may counteract an overwhelming sensory environment, or alleviate the high levels of internal anxiety these kids typically feel every day". A real life example is that it could stop sounds hurting your ears.
As an adult, Grandin seems to control the sensory overload a little better but says some people need to stim to "refocus and realign their systems".
UK campaigner Robyn Steward says she relaxes her wrists and lets her hands flap up and down when she's happy or anxious. A public speaker with autism, Stewart thinks that for her, it's the rhythmic nature of stimming that does the trick. "When babies don't sleep well, you put them in the car, in their car seat, and you drive about. They are lulled to sleep by the sound and the movement because they feel safe." The repetitive sound, she says, is a good example of a stim outside of the context of autism.
So, in short, stimming is often done to block unwanted sounds or visuals through distraction, or to bring focus. Not all noises and movement are stims - these have a purpose. Tics, for instance, are purposeless.
Is it just people on the autism spectrum who stim?
No. Neurotypicals, or people without autism (you, maybe?), also self-stimulate; nail biting, hair twirling and foot tapping all count as stims.
NTs, as they're known for short, can usually control their stims and tend to do ones that are considered more acceptable in public than those done by people with autism.
There are blogs and web forums where people on the spectrum discuss stimming, compare stims and discuss public reactions.
Should stimming be stopped?
Welcome to Controversyville, come in, take a seat.
"Quiet hands" is a gentle request you might hear from teachers or parents in the US encouraging children to stop stimming. The consensus between autism experts now seems to favour not intervening unless it's causing harm, no matter that it may look a bit different or cause others to feel uncomfortable.
On the Talk About Autism forum, a contributor called Claire (who is on the spectrum herself), writes: "[Stopping stims is] a bit like 'teaching' someone who is blind not to feel things in a room to find out where they are because we don't like them putting their arms and hands out to do so.
"It has a purpose. Stopping it in order to make others feel better seems bizarre to me."