A new study indicates that autistic and non-autistic individuals express emotions differently through facial movements. This may contribute to misunderstandings of emotional expressions between these groups.
Researchers at the University of Birmingham utilized detailed facial motion tracking to create a library of facial expressions associated with emotions such as anger, happiness, and sadness. The study collected over 265 million data points.
The research, published in Autism Research, involved 25 autistic and 26 non-autistic adults, who collectively produced nearly 5,000 expressions. Participants generated angry, happy, and sad facial expressions in two contexts: in synchrony with sounds and while speaking. Differences in these expressions were observed between the groups, with autistic participants also producing a higher number of unique expressions.
Specific findings included:
- For anger, autistic participants demonstrated greater reliance on the mouth and less on the eyebrows compared to non-autistic participants.
- For happiness, autistic participants exhibited a less exaggerated smile that did not appear to extend to the eyes.
- For sadness, autistic participants produced a downturned expression by raising their upper lip more than their non-autistic counterparts.
The study also found that alexithymia, a condition often present in autism involving difficulties in identifying and describing one's own emotions, influenced facial expressions. Alexithymia was associated with less distinct angry and happy expressions, potentially making them more ambiguous.
Dr. Connor Keating, who conducted the research and is now with the University of Oxford, stated that the findings suggest differences in both the appearance and the smoothness of facial expression formation between the groups. He indicated that these mismatches might explain difficulties in recognizing expressions between autistic and non-autistic individuals.
Professor Jennifer Cook, a senior author from the University of Birmingham, suggested that autistic and non-autistic individuals may express emotions in distinct but equally meaningful ways, likening it to different languages. She added that what has been perceived as difficulties for autistic people might instead indicate a mutual challenge in understanding each other's expressions.
The project received funding from the Medical Research Council (MRC, United Kingdom) and the European Union's Horizon 2020 Research and Innovation Programme.