Dysfunction in interpersonal neural synchronization as a mechanism for social impairment in autism spectrum disorder.
Live conversation breaks down when TPJ brain waves between partners drift out of sync, and this drift is sharper in adults with autism.
01Research in Context
What this study did
Adams et al. (2021) watched adults talk in pairs. One person had autism, the other did not.
The team used fNIRS helmets to measure brain activity at the same time in both speakers.
They focused on the temporo-parietal junction, or TPJ, a social hot spot near the back of the brain.
What they found
Adults with autism showed weaker real-time brain-to-brain coupling in the TPJ during conversation.
Lower coupling matched higher parent-rated social trouble.
Typical adults kept their TPJ signals in step; the autism group did not.
How this fits with other research
Chien et al. (2015) first saw TPJ problems in boys with autism, but at rest. They found too much wiring, not too little.
E et al. now show the flip side during live talk: under-synchrony between people, not over-connectivity within one brain.
David et al. (2014) linked smaller TPJ gray matter to worse social perception. The new study adds a moment-to-moment timing problem that may flow from that structure.
Li et al. (2025) report weak right-hemisphere social-visual cables in children. Together the papers trace a line: from kids to adults, from seeing faces to holding chats, the back-right social circuit keeps misfiring.
Why it matters
You now have a clear, brain-based reason why some adults with autism look “out of sync” in conversation. It is not lack of will; their TPJ clocks do not align with yours.
When you teach social skills, add turn-taking drills that give extra time for neural catching-up. Slow the pace, use clear pauses, and let the learner reset. These tiny scaffolds may help the TPJ find the beat.
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02At a glance
03Original abstract
Social deficits in autism spectrum disorder (ASD) have been linked to atypical activation of the mentalizing network. This work, however, has been limited by a focus on the brain activity of a single person during computerized social tasks rather than exploring brain activity during in vivo interactions. The current study assessed neural synchronization during a conversation as a mechanism for social impairment in adults with ASD (n = 24) and matched controls (n = 26). Functional near-infrared spectroscopy (fNIRS) data were collected from the prefrontal cortex (PFC) and tempoparietal junction (TPJ). Participants self-reported on their social communication and videos of the interaction were coded for utterances and conversational turns. As expected, controls showed more neural synchrony than participants with ASD in the TPJ. Also as expected, controls showed less social communication impairment than participants with ASD. However, participants with ASD did not have fewer utterances compared with control subjects. Overall, less neural synchrony in the TPJ was associated with higher social impairment and marginally fewer utterances. Our findings advance our understanding of social difficulties in ASD by linking them to decreased neural synchronization of the TPJ. LAY SUMMARY: The coordination of brain responses is important for efficient social interactions. The current study explored the coordination of brain responses in neurotypical adults and adults with ASD to investigate if difficulties in social interactions are related to difficulties coordinating brain responses in ASD. We found that participants with ASD had more difficulties coordinating brain responses during a conversation with an interacting partner. Additionally, we found that the level of coordination in brain responses was linked to problems with social communication.
Autism research : official journal of the International Society for Autism Research, 2021 · doi:10.1016/j.ijpsycho.2019.01.003