The Neuroscience of Stimming: Why Repetitive Movement Can Help Regulate the Brain

Have you ever been told to stop flapping, stop rocking, stop tapping, or stop humming? I have, many times. Maybe that happened in a classroom, at the dinner table, or in a therapist's office (that was supposed to help).

Here's what nobody told us back then: that movement isn't a problem. It's our nervous system doing its job.

For a long time, clinical thinking has treated stimming — repetitive movements, sounds, or actions like hand-flapping, rocking, humming, or finger-flicking — as a symptom to eliminate. Something to train out. The newer neuroscience tells a very different, much more respectful story: stimming may be one of the most sophisticated self-regulation tools our brain has.

Want to find out more? Okay! Let's get into the actual biology, because it's fascinating!

What's Happening In The Body?

Your brain might be making its own calming medication. One of the earliest and most striking findings in this area came from a 1987 study that looked at what happens when the brain's opioid receptors are blocked in a person who engages in repetitive self-stimulatory behavior. When researchers administered naloxone — a drug that blocks opioid receptors — the self-stimulatory behavior changed measurably. This suggests that repetitive movement appears to trigger the release of the brain's own endogenous opioids — its internal, homemade calming and pleasure chemicals. In other words, stimming isn't just "a habit." It may be a form of self-administered neurochemical regulation, happening in real time, without you ever consciously deciding to do it.

Autistic brains may process self-generated sensation differently — and that difference might explain a lot. A 2025 study out of the University of Rochester used EEG and virtual reality to compare how autistic and non-autistic adults' brains respond to touch they generate themselves versus touch that happens to them passively. In non-autistic brains, there's a well-known phenomenon called sensory suppression — your brain automatically dampens its response to sensations you cause yourself (this is part of why you can't tickle yourself). The autistic adults in this study showed something different: their brains responded to self-generated touch almost the same way they responded to passive touch, without that typical dampening. The researchers suggest this could point to a difference in how the brain predicts the sensory consequences of its own actions — and that this exact mismatch may be part of what drives repetitive, self-generated movement in the first place. If your brain isn't automatically "expecting" and discounting your own movement the way most people's do, generating a strong, predictable, repeatable sensation (like rocking or flapping) may be one of the clearest ways to get reliable sensory feedback in a world that otherwise feels sensorially unpredictable.

It's not just regulation — it's connection, too. Here's where the newer research gets genuinely fascinating. A 2025 study surveyed 131 autistic adults directly about their own experiences of stimming — not clinicians' observations about them, but their actual first-person accounts. The findings pushed back hard on the old "stimming is just self-regulation" framing. Participants described stimming as something that fostered real connection with other autistic people, helped signal and recognize emotional states in one another, and was frequently a genuinely positive, even joyful, experience — not merely a coping mechanism to be tolerated. Notably, when participants did suppress their stimming, it was almost always for one reason: to avoid judgment from other people — not because they personally wanted to stop. An earlier landmark study of autistic adults' own perspectives found a similar throughline: autistic people overwhelmingly wanted stimming to be accepted, not eliminated, describing it as something that helped them feel calm, expressed genuine emotion (including excitement and joy, not just distress), and was rarely something they wanted "fixed."

How Stimming Is Perceived

To the autistic brain, stimming can feel like: "This is how I return to my body. This is how I know where I am, how I feel, and that I'm safe — and sometimes, it's just how I feel joy."

To an outside observer, it can look like: a behavior that seems "off" or in need of correction, disconnected from any obvious purpose — something to redirect toward looking "more normal."

That gap isn't a difference in what's actually happening — it's a difference in whether the function of the behavior is visible from the outside. The movement isn't empty. It's doing real neurological and emotional work, even when that work is invisible to everyone except the person doing it.

What Do We Do?

• Separate "different" from "dangerous." Most stimming is neither harmful nor something that needs to be stopped. The research consistently distinguishes self-injurious behavior (which does warrant support and intervention) from the vast majority of stimming, which is safe, regulating, and sometimes simply joyful.

• Notice what a stim is doing for you before trying to replace it. Is it calming an overwhelmed system? Adding needed stimulation to an understimulated one? Expressing excitement? The "why" should guide any response — including your own — far more than how it looks to others.

• If suppression is happening, ask why. Given the research showing suppression is driven almost entirely by fear of judgment rather than personal preference, it's worth gently asking yourself (or a loved one): am I masking this because it isn't serving me, or because I'm afraid of how it looks?

• Let go of "quiet hands" as a goal in itself. Historically, many interventions targeted stopping stimming outright. Current understanding suggests this may remove a genuine coping and connection tool without replacing what it was providing — the goal should be regulation and wellbeing, not the appearance of stillness.

  
  

Getting The Right Support

Stimming was pathologized for decades because it looked unusual from the outside. But underneath that "unusual" surface is a brain actively regulating itself — sometimes chemically, sometimes sensorially, sometimes socially — using one of the most efficient tools available to it. What looked like a problem to solve turns out to be evidence of a nervous system doing exactly what it's supposed to do: taking care of itself.

If you've spent years being told to suppress the very things that helped you regulate, it might be worth revisiting that with fresh eyes — and fresh science.

If this resonates and you're curious what it might mean for your own patterns, the RAADS-14 screener a good low-pressure starting point.

The Ritvo Autism and Asperger Diagnostic Scale (RAADS-14) is a validated screening tool designed for adults. It takes only a few minutes and can be a meaningful first step toward understanding yourself more fully.

And if you're ready to talk to someone who understands your stimming, our team at the Adult Autism Assessment Center offers free consultations. We work with adults. We listen. We don't simplify.

You can also book a free consultation with one of our therapists. We specialize in seeing the whole picture, not just the highlight reel. 

And if you're tired of being mistranslated, our team of neurodiversity-affirming clinicians at the Adult Autism Assessment Center would love to meet you, the real, warm, deeply-feeling you. You can book a free consultation with any of us anytime.

Our clinic She Rocks The Spectrum is centered around women and girls, while our clinic Therapy 4 Autistic Men is focused on men and boys.

Warmly,

Michelle Karth, PhD, PhD Behavioral Neuroscience 

Autism Advocate 

Scientific Advisor

Adult Autism Assessment Center

Science Resources

References

Isenstein, E. L., Freedman, E. G., Rico, G. A., Brown, Z., Tadin, D., & Foxe, J. J. (2025). Adults on the autism spectrum differ from neurotypical peers when self-generating but not passively-experiencing somatosensation: A high-density electrophysiological (EEG) mapping and virtual reality study. NeuroImage, 311, 121215. https://doi.org/10.1016/j.neuroimage.2025.121215

Kapp, S. K., Steward, R., Crane, L., Elliott, D., Elphick, C., Pellicano, E., & Russell, G. (2019). 'People should be allowed to do what they like': Autistic adults' views and experiences of stimming. Autism, 23(7), 1782–1792. https://doi.org/10.1177/1362361319829628

Morris, I. F., Sykes, J. R., Paulus, E. R., Dameh, A., Razzaque, A., Esch, L. V., Gruenig, J., & Zelazo, P. D. (2025). Beyond self-regulation: Autistic experiences and perceptions of stimming. Neurodiversity, 3. https://doi.org/10.1177/27546330241311096

Sandman, C. A., Barron, J. L., Crinella, F. M., & Donnelly, J. F. (1987). Influence of naloxone on brain and behavior of a self-injurious woman. Biological Psychiatry, 22(8), 899–906. https://doi.org/10.1016/0006-3223(87)90079-4