Pupillometric measures of altered stimulus-evoked locus coeruleus-norepinephrine activity explain attenuated social attention in preschoolers with autism spectrum disorder.
Pupil tracking shows preschoolers with autism miss social motion because their bodies under-react, not over-react.
01Research in Context
What this study did
The team watched preschoolers’ pupils while the kids viewed short clips.
Some clips showed people moving. Others showed shapes spinning.
Kids were autistic or typically developing. No extra tasks, just looking.
What they found
Autistic pupils barely changed to social motion.
The same pupils widened big when geometric shapes spun.
This mismatch explains why the kids looked less at people.
How this fits with other research
Root et al. (2017) first saw odd pupil reflexes in young autistic kids. Leonie et al. now link those reflexes to social scenes, not just light.
Lemons et al. (2015) found no pupil jump when autistic kids met someone’s eyes. The new study shows the gap appears only when bodies move, not during still gaze.
Sigman et al. (2003) saw heart-rate slowing, not speeding, during social video. Leonie et al. add pupil data and point to under-reactivity, not over-arousal, as the core issue.
Pan et al. (2025) later paired heart-rate with eye-tracking and got the same flat arousal picture, building a fuller bio-story.
Why it matters
You can stop guessing that eye contact hurts. The body says the child simply does not register social motion as important.
Try pairing people with strong sensory props—music, bounce, or light—so the child’s pupil finally tags the scene as worth watching.
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02At a glance
03Original abstract
Attenuated social attention has been described as a reduced preference for social compared to geometric motion in preschoolers with autism spectrum disorder (ASD). The locus coeruleus-norpinephrine (LC-NE) system modulates sensory reactivity and is a promising underlying mechanism. LC-NE activity is indexed by a stimulus-evoked pupillary response (SEPR) and partially by a luminance-adaptation pupillary response (LAPR), which were both shown to be aberrant in ASD. We examined whether SEPR and LAPR explain an attenuated social motion preference. We applied pupillometry via video-based eye tracking in young children (18-65 months) with ASD (n = 57) and typically developing (TD) children (n = 39) during a preferential looking paradigm of competing social and geometric motion and a changing light condition paradigm. We found an attenuated social motion preference in the ASD compared to the TD group. This was accompanied by atypical pupillometry showing a smaller SEPR to social motion, a larger SEPR to geometric motion and a reduced LAPR to a dark screen. SEPR but not LAPR explained the group difference in social motion preference. An ASD diagnosis was statistically predicted by the social motion preference, while this effect was mediated by the inclusion of SEPR to geometric and social motion. Our findings suggest a decreased sensory reactivity to social and increased reactivity to non-social motion in ASD, which may concurrently contribute to an attenuated social attention. The LC-NE system is supported as a promising underlying mechanism of altered social attention in young children with ASD, while the specificity of findings remains to be addressed.
Autism research : official journal of the International Society for Autism Research, 2022 · doi:10.1002/aur.2818