Both the mirror and the affordance systems might be impaired in adults with high autistic traits. Evidence from EEG mu and beta rhythms.
Adults who score high on autism traits show quiet mirror-neuron and affordance brain waves when they watch actions or see tools.
01Research in Context
What this study did
de Vega et al. (2019) hooked adults with high autistic traits to an EEG cap. They showed short clips of hands using tools and pictures of tools you can pick up. The team checked two brain rhythms: mu (linked to mirror neurons) and beta (linked to object affordances).
They wanted to know if subtle autism traits weaken the brain’s ‘copy’ signal and its ‘I know what to do with this’ signal.
What they found
Both rhythms stayed flat. High-trait adults had weak mu suppression when watching actions and weak beta bursts when viewing graspable objects. The mirror and affordance systems looked sleepy compared to typical brains.
How this fits with other research
Poljac et al. (2013) already showed the same adults read angry or sad faces poorly; Manuel adds that their action-brain waves are off, too. The story extends from faces to hands and tools.
Cook (2010) seems to disagree. That study found normal mu suppression in diagnosed ASD adults. The clash clears up when you see the groups: H tested people with full ASD; Manuel tested neurotypical adults who only score high on autism questionnaires. Sub-clinical traits may show EEG dips that clinical samples miss.
Murphy et al. (2014) and Manuel both find odd EEG rhythms in autism, but in different bands. W showed kids with ASD lack alpha ‘filter’ waves when distractors appear; Manuel shows adults with high traits lack mu/beta waves to actions and objects. Together they map a wider EEG signature of processing gaps.
Why it matters
If a client has high autism traits but no diagnosis, don’t assume typical brain responses. Video modeling or tool-use chains may need extra repetition because the mirror and affordance systems are less engaged. Try combining action clips with physical practice and clear object labels to wake up both networks.
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02At a glance
03Original abstract
The association of autism spectrum disorder (ASD) with an altered mirror neuron system is still controversial. At the same time, the processing of object affordances by persons with ASD is a neglected issue. In this electroencephalographic study, adults differing in their autism quotient (AQ) scores were selected. We found anomalous modulation of mu and beta rhythms in high-AQ, compared to low-AQ persons, while they watched a set of goal-directed manual actions. This confirms that observing actions involving implicit intentions most clearly reveals the impairment of the mirror neurons system (MNS). The high-AQ group also showed anomalous mu and beta modulation when they looked at pictures of manipulable objects, indicating a deficit in processing motor affordances. We conclude that high-AQ adults have neural impairment of both the MNS and the affordance systems, which could underlie their relational problems with both people and objects. Autism Res 2019, 12: 1032-1042. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Adults with autistic traits (high-autism quotient [AQ] scores) and matched controls (low-AQ) observed intentional hand actions, and pictures of manipulable and non-manipulable objects. The high-AQ group compared to the control group, showed anomalous modulation of the electroencephalographic motoric rhythms (mu and beta) while observing familiar goal-directed actions, confirming an impairment of their mirror neuron system. Also, their brain rhythms were anomalous when they watched manipulable objects, which suggest a dysfunction in their relation with objects (affordance system).
Autism research : official journal of the International Society for Autism Research, 2019 · doi:10.1002/aur.2121