Autistic and non-autistic individuals display differences in how they express emotions through facial movements, according to new research from the University of Birmingham. The study, published in Autism Research, involved 25 autistic and 26 non-autistic adults who produced nearly 5,000 facial expressions representing anger, happiness, and sadness.
Researchers used detailed facial motion tracking to analyze over 265 million data points, creating a comprehensive library of emotional expressions. Participants were asked to make facial expressions both in synchrony with sounds and while speaking. The results showed that autistic participants not only differed in their angry, happy, and sad expressions compared to non-autistic participants but also produced more unique types of expressions.
The study also examined the impact of alexithymia—a condition often present in autism characterized by difficulty identifying and describing one’s own emotions—on facial expression. The researchers found that higher levels of alexithymia were associated with less distinct angry and happy expressions, making them appear more ambiguous.
Dr Connor Keating, who led the research at the University of Birmingham and is now at the Department of Experimental Psychology at the University of Oxford, stated: "Our findings suggest autistic and non-autistic people differ not only in the appearance of facial expressions, but also in how smoothly these expressions are formed. These mismatches in facial expressions may help to explain why autistic people struggle to recognize non-autistic expressions and vice versa."
The project received funding from the Medical Research Council (MRC) in the United Kingdom as well as support from the European Union's Horizon 2020 Research and Innovation Programme.
