Why Some Autistic People Dislike Hugs: New Study Reveals a Neural Reason
Wednesday, July 16, 2025.
Social Touch Isn’t Always Soothing—Especially for Autistic Brains
For most people, a gentle hug or a friendly pat on the back is comforting. It's a form of wordless communication—something we instinctively recognize as social, meaningful, and safe.
But for some folks on the autism spectrum, especially those with sensory sensitivities, touch can feel overwhelming or even invasive.
Why is that?
New research published in Nature Communications (Chari et al., 2024) offers a compelling, brain-based explanation.
In a mouse model of Fragile X syndrome—a leading genetic cause of autism—scientists found that the animals' neurons simply didn’t distinguish between social and non-social touch.
For these mice, a plastic object and another mouse brushing against them triggered the same reaction: aversion.
This neural confusion may explain why many autistic individuals find all touch—regardless of intent—unpleasant.
Autism, Fragile X, and the Biology of Social Touch
Researchers at UCLA, led by neuroscientist Carlos Portera-Cailliau and doctoral researcher Trishala Chari, set out to explore a basic but important question:
What happens in the brain when social touch isn’t recognized as social?
They used Fmr1 knockout mice, which are genetically engineered to model Fragile X syndrome. These mice exhibit behaviors that closely resemble sensory hypersensitivity and social withdrawal found in humans with autism.
Using high-tech Neuropixels probes, the team recorded brain activity from three regions:
Somatosensory cortex (touch processing)
Basolateral amygdala (emotional significance)
Tail of the striatum (decision-making based on sensation)
The experiment involved exposing each mouse to two types of interactions:
Social touch: from another mouse
Non-social touch: from a plastic tube
These interactions were further divided into voluntary (the mouse initiates contact) and forced (the object or mouse is brought into the test animal’s personal space).
Key Finding: The Autistic Brain May Not Know the Difference
Here’s where it gets fascinating.
In wild-type (typical) mice, the brain showed distinct patterns for social and non-social touch. Neurons fired differently depending on whether the contact came from another mouse or an object.
In Fragile X mice, that distinction vanished.
“Neurons from Fmr1 knockout mice fired more similarly to both presentations,” said Portera-Cailliau. “At the network level, the brain could not discriminate between social and non-social stimuli.” (Chari et al., 2024)
Behaviorally, the mice mirrored this confusion. While typical mice avoided forced object touch but tolerated social contact, Fragile X mice reacted negatively to both. Eye squinting, whisker protraction, and withdrawal behaviors were common—even during voluntary social interactions.
Why This Study Matters for Autism and Sensory Sensitivity
This research provides a biological framework for understanding why many autistic individuals dislike being touched—even by people they love. It suggests that their brains may not assign emotional or social meaning to touch in the same way.
Rather than interpreting physical contact as connection, the brain may process it as just another unpleasant stimulus.
Clinical Implications:
Don’t assume touch is comforting. Always ask for consent, even from young children.
Voluntary interaction matters. People are more tolerant of sensory input when they initiate it themselves.
Offer alternatives. Eye contact, shared activities, or even parallel play can be just as meaningful.
This also raises important questions for therapy. Should interventions attempt to increase tolerance for touch—or shift entirely to non-touch forms of connection?
What Therapists, Parents, and Partners Should Know
If you're working with or caring for someone on the autism spectrum, keep this in mind: Touch sensitivity isn’t a preference—it’s a brain-based difference.
Rather than “too much feeling,” it may be about not knowing what to feel.
This makes consent and predictability crucial. The same social gesture that feels connecting to one person may feel threatening to another—not because they don’t care, but because their neural wiring says this is unpleasant.
As Portera-Cailliau noted:
“Social avoidance in Fragile X syndrome or autism could relate to differences in neuronal activity. By tweaking that activity, it may be possible to help individuals better tolerate social interactions they find uncomfortable.” (Chari et al., 2024)
That future is still on the horizon. But for now, empathy starts with understanding.
Final Thoughts: Social Isn’t Always Safe
It’s easy to assume that all humans (and all mice) crave connection in the same way. But this study reminds us that not everyone experiences touch—or intimacy—the same.
For some, especially those with autism or Fragile X syndrome, physical contact doesn’t signal love. It signals confusion. Or worse, danger.
Rather than forcing connection through touch, we might do better to ask, “What feels safe to you?”
Maybe that’s the most human gesture of all.
Be Well, Stay Kind, and Godspeed.
REFERENCES:
Chari, T., Hernandez, A., Couto, J., & Portera-Cailliau, C. (2024). A reduced ability to discriminate social from non-social touch at the circuit level may underlie social avoidance in autism. Nature Communications.https://doi.org/10.1038/s41467-024-XXXX-Y
Cascio, C. J., McGlone, F., Folger, S., Tannan, V., Baranek, G. T., Pelphrey, K. A., & Essick, G. K. (2008). Tactile perception in adults with autism: A multidimensional psychophysical study. Journal of Autism and Developmental Disorders, 38(1), 127–137. https://doi.org/10.1007/s10803-007-0370-8
McKernan, E. G., Smith, S. J., & Robles, M. R. (2023). Sensory over-responsivity and social participation in children with autism spectrum disorders: A scoping review. Research in Autism Spectrum Disorders, 104, 102090. https://doi.org/10.1016/j.rasd.2023.102090