The behavioural and inter-brain dynamics between a person with autism and a neurotypical person are different than those between two neurotypical people.

That’s the conclusion of a new study by Guillaume Dumas, principal investigator at the Precision Psychiatry and Social Physiology Laboratory at the Centre de recherche Azrieli du CHU Sainte-Justine and professor in the Department of Psychiatry and Addiction at Université de Montréal.

Dumas is also an associate academic member of Mila – Quebec Artificial Intelligence Institute, and holds the IVADO Chair in Artificial Intelligence and Mental Health.

Not on the same wavelength

Dumas and his team conducted an experiment to study imitations of hand movements in pairs of neurotypical individuals compared with a neurotypical individual paired with a person with autism.

The subjects were seated in separate rooms and could see their partner’s hand movements on a screen. They were instructed to make meaningless gestures and were left free to imitate their partner’s movements or not. Their behaviour was videotaped.

The research team also measured the pairs’ inter-brain synchrony pairs using EEG hyperscanning, a technique that can simultaneously record brain activity in multiple subjects. Several years ago, Dumas demonstrated that human brains tend to spontaneously synchronize when engaged in social interaction, i.e. their electrical rhythms oscillate at the same frequency.

This new study found that the synchronization between a person with autism and a neurotypical person is less close than between two neurotypical people. It also found that people with autism were more likely to be followers than leaders in imitating hand movements.

“We found that the autistic subjects were just as capable of reproducing their partner’s behaviour and synchronizing their movements with them,” said Dumas. “But they differed in ‘turn-taking’: they were less likely to initiate a movement.”

It's not you, it's us

Dumas believes the difference in turn-taking but not in ability to imitate suggests that autism is “a relational condition rather than a disorder specific to the individual.” This interpersonal perspective shifts the focus away from individual (dis)abilities.

“Impaired social interaction is bidirectional,” Dumas said. “But we never say that a neurotypical person has a deficit in social cognition when they have a hard time understanding a person with autism. When an interaction is more difficult, the responsibility lies with everyone involved.”

By adopting an interpersonal perspective on autism that takes diversity into account, Dumas hopes to pave the way for a more preventative and inclusive approach to mental health.