Separate contributions of autistic traits and anxious apprehension, but not alexithymia, to emotion processing in faces.

Reduced eye fixation has been commonly reported in autistic samples but may be at least partially explained by alexithymia (i.e., difficulty understanding and describing one's emotional state). Because anxiety is often elevated in autism, and emotion-processing differences have also been observed in anxious samples, anxiety traits may also influence emotion processing within autism. This study tested the contribution of dimensional traits of autism, anxious apprehension, and alexithymia in mediating eye fixation during face processing. Participants included 105 adults from three samples: autistic adults (AS; n = 30), adults with clinically elevated anxiety and no autism (HI-ANX; n = 29), and neurotypical adults without elevated anxiety (NT; n = 46). Experiment 1 used an emotion identification task with dynamic stimuli, while Experiment 2 used a static luminance change detection task with emotional- and neutral-expression static photos. The emotions of interest were joy, anger, and fear. Dimensional mixed-effects models showed that autism traits, but not alexithymia, predicted reduced eye fixation across both tasks. Anxious apprehension was negatively related to response time in Experiment 1 and positively related to eye fixation in Experiment 2. Attentional avoidance of negative stimuli occurred at lower levels of autism traits and higher levels of worry traits. The results highlight the contribution of autism traits to emotional processing and suggest additional effects of worry-related traits.