The efficient processing of social information from the environment is critical for survival. For example, direct gaze captures attention and is rapidly detected in a visual search task, a phenomenon known as the eye contact effect (Senju & Johnson 2009). Similarly, fearful stimuli has been shown to also capture attention and be detected faster than non-fearful stimuli. We thus used eye contact as a typical example of social information and fearful faces as an example of threat. Using behavioral measures like eye movements and skin conductance responses, in combination with neural measures from functional magnetic resonance imaging, we investigated whether and to what extent the processing of such information depends on awareness. In a series of experiments, we first showed that gaze direction can be processed unconsciously and typically developed (TD) adults have a bias towards faces with direct gaze even when these faces are presented outside of awareness. Interestingly, individuals with autism spectrum disorder (ASD) have an unconscious avoidance of direct gaze. Neurally, faces with direct gaze require less neural activity to reach awareness compared to faces with an averted gaze providing a neural basis for the access of direct gaze to awareness. Finally, we observed that eye movements were not biased towards an aversively conditioned fearful face when presented outside of awareness. These results suggest that eye gaze information is initially processed through a subcortical, quick and dirty pathway involving the amygdala and superior colliculus. Further they indicate that eye avoidance in ASD is an involuntary and automatic effect. Finally, they show that awareness might be necessary to observe the commonly reported attentional bias towards aversive stimuli providing a limit for the unconscious processing of social stimuli.
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