Exploring the Broader Autism Phenotype: How Alexithymia Impacts Recognition of Facial Expressions of Pain

Autism spectrum disorder has been associated with deficits in socio-emotional interactions; however, research results are not homogenous in this regard. To explain this variety of observations, the alexithymia hypothesis suggests that impaired emotion processing in autism is due to co-occurring alexithymia. Furthermore, while DSM-5 references altered responses to painful stimuli in individuals with autism, the discussion continues regarding their ability in recognizing painful facial expressions. The Broader Autism Phenotype theory also posits that ASD represents an extreme of a spectrum of autistic traits present in the general population. This study investigates the perceptual sensitivity threshold for recognizing painful facial expressions and gaze behavior among individuals with high and low autistic traits.

A total of 462 participants completed the Autism-Spectrum Quotient (AQ-50) and the Toronto Alexithymia Scale (TAS-20). Among them, 35 individuals were assigned to the high-AQ group (66% female) and 31 were assigned to the low-AQ group (68% female). Participants performed a facial expression recognition task and had their eye movements recorded, then completed the Depression, Anxiety, and Stress Scale and the Interpersonal Reactivity Index.

Results revealed no significant differences between groups in sensitivity thresholds or visual attention patterns, although a notable correlation existed between alexithymia and sensitivity thresholds.

These findings support the alexithymia hypothesis, indicating that difficulties in recognizing pain through facial expressions relate to alexithymia, not to autistic traits. Specifically, our results contradict previous studies suggesting reduced gaze duration at faces in autistic individuals.