Face perception without subjective awareness - Emotional expressions guide early gaze behavior in clinically depressed and healthy individuals

Background: Major depressive disorder is associated with attentional biases in the explicit processing of emotional facial expressions. It is unclear if attentional biases for emotional faces also exist at an automatic level of perception.

Method: Gaze behavior of twenty-nine clinically depressed individuals and twenty-nine gender matched healthy controls was compared in an affective priming task. Happy, neutral, sad, angry, and fearful facial expressions were presented very briefly as primes with forward and backward masking, followed by a neutral expression. Participants' early gaze behavior on neutral faces was analyzed for the eyes and mouth as areas of interest. Only participants who were subjectively unaware of the emotional prime faces were included in the analyses.

Results: Masked emotional facial expressions elicited early eye movements toward diagnostic features of the face. Both, depressed patients and healthy controls oriented their initial fixation on the face more often to the eye region after the presentation of fearful or sad compared to happy primes. However, depressed patients oriented their gaze generally far less to the eye and mouth region compared to healthy controls.

Limitation: Awareness of emotional prime faces was assessed by a systematic interview but not by an objective detection task.

Conclusion: Our data suggest enhanced attentional orienting toward the eye region due to fearful and sad faces in depressed and healthy individuals. In spite of this early expression-specific vigilance, depressed individuals oriented their gaze overall less to the eyes and mouth compared to healthy controls, which might represent an avoidance of facial features.