The association between socio-communicative traits associated with Autism and pupillary responses to dynamic, audiovisual emotional speech

Autistic individuals commonly exhibit difficulties with emotion recognition, difficulties that contribute to social issues in Autism. Both emotion recognition and social abilities are distributed along a spectrum in Autism and the general population. We explored this relationship between emotional processing, as measured via the physiological response of pupil dilation, and Autistic traits, including social abilities. We presented participants with dynamic, audiovisual stimuli of actors uttering a semantically neutral phrase. These utterances were expressed with either neutral tone of voice and facial expression, or with angry, fearful, disgusted, sad, or surprised tone and expression. Each emotion was presented with high- and low-intensity depictions. Participants were asked to identify the emotion and rate its intensity. Participants’ pupillary responses were recorded during viewing. Traits associated with Autism were measured through a battery of self-report scales. We then tested for associations between Autistic traits and pupillary response to emotional stimuli. Broadly speaking, individuals with higher Autistic traits exhibited smaller overall pupillary responses to emotional stimuli. More specifically, emotional responses were related to socio-communicative Autistic traits. Further, social traits were especially correlated with physiological responses to low-intensity emotional presentation. This reflects previous studies suggesting that Autistic individuals show more pronounced difficulties with emotion recognition when emotional expression is more subtle. Finally, social Autistic traits were related to physiological responses to anger, fear, surprise, and to a lesser extent happiness, but not to sadness or disgust.