Attentional bias toward threatening emotional faces in individuals with autism spectrum disorder: A meta-analysis on reaction time tasks

Background: Social differences for individuals with autism spectrum disorder (ASD) could be related to attentional bias toward threatening emotional faces. However, studies investigating this attentional bias in individuals with ASD vary in paradigms and results. Methods: We conducted a meta-analysis across different reaction time tasks, including dot-probe, spatial cuing, visual search and emotional Stroop tasks, to examine the attentional bias toward threatening emotional faces in individuals with ASD. Narrative synthesis further summarized possible moderators affecting attentional bias. Results: We used systematic searches to identify 21 empirical studies with 1,805 participants in total (ASD n = 909). Individuals with ASD showed a small but significant attentional bias toward threatening emotional faces over other faces (g = 0.162), which was similar to individuals with typical development (g = 0.203). Moderator analysis showed that adults with ASD showed a larger attentional bias than children with ASD. For the dot-probe and spatial cuing paradigms, attentional bias toward threatening emotional faces was observed when stimuli were presented for less than 500 ms, and bias away from threatening emotional faces was shown when stimuli were presented for over 500 ms. For the visual search paradigm, attentional bias was significant in button-press tasks, but not in touch-screen tasks. Furthermore, attentional bias was only observed when the stimuli were schematic faces and reference materials were happy faces. Conclusions: Individuals with ASD showed a small but significant attentional bias toward threatening emotional faces. Furthermore, significant moderators included stimulus presentation, response type, reference face type, stimulus type, and age. Thus, more research is needed to further explore attentional bias toward threatening emotional faces in individuals with ASD.