The Role of Callous- and Unemotional Traits in Emotional Face Processing in Adolescents with ASD or ODD/CD

Background: Facial expressions are important for understanding others’ emotions and feelings. Individuals with psychiatric disorders such as Autism Spectrum Disorder (ASD), Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD) show deficits in the processing of emotional faces. A common factor in these psychiatric disorders is the lack of empathy (Decety & Moriguchi, 2007). More recently, evidence pointed to a potential role of callous- and unemotional traits (CU traits) in emotional processing deficits in ASD and ODD/CD (Dadds et al., 2006; Leno et al., 2015). In ASD half of the adolescents show high levels of CU traits (Leno et al., 2015). In this study we used eye-tracking and questionnaires to compare facial emotion processing in adolescents with ASD, ODD/CD and typically developing controls (TDC), and examined the modulatory role of CU traits.

Objectives: Investigate the role of CU traits in gazing behavior towards emotional faces in a large sample of male adolescents with ASD, ODD/CD or typical developing controls.

Methods: A total of 122 male participants (N=42 ODD/CD, N=52 ASD, and N=28 (TDC) were included in the current study (age range: 12-19 years, mean = 15.4, SD = 1.9). We took a novel non-parametric trial-based approach to investigate the time-wise proportionality of looking behavior to specific regions of interest (ROIs) in emotional faces. As ROIs we selected the eyes region (both eyes within the ROI), the mouth region and the rest of the image. For every ROI we investigated total fixation duration, percentage of first fixation to ROI, and time to first fixation to a ROI in miliseconds. We used Kruskal Wallis one-way ANOVA to examine eye tracking patterns across facial emotions (neutral, anger, fear, sadness and happiness) and diagnostic groups. Furthermore, we investigated the correlation between eye gazing for emotional faces with CU traits by using the parent rated total scores of the Inventory of Callous-Unemotional Traits (ICU)questionnaire and the Youth Psychopathic Traits Inventory (YPI).

Results: We observed significant group differences for the time to first fixation towards the eye region for fearful faces using a Kruskal Wallis One-way ANOVA (X² (DF=2, N=248) = 6.11, p=0.0471). Compared to controls, the ASD and CD/ODD group took significant longer time to fixate on the eyes of a fearful face. For the mouth region we did not find significant differences. Moreover, for the other emotions and neutral facial expression we did not find significant group differences. When examining the role of CU traits we observed a significant positive correlation between time to first fixation for fearful faces and CU traits in both the ASD and ODD/CD group.

Conclusions: Our findings correspond with previous findings from eye-tracking studies that report deficits in the processing of fearful faces in both adolescents with ASD or ODD/CD. We were able to pinpoint more precisely eye-tracking gazing behavior in these clinical groups. Our data suggest that callous and unemotional traits play a modulating role in fear processing in both male adolescents with ASD or ODD/CD.