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Abstract: This study investigated the neurocognitive mechanisms underlying the role of the eye and the mouth regions in the recognition of facial happiness, anger, and surprise. To this end, face stimuli were shown in three formats (whole face, upper half visible, and lower half visible) and behavioral categorization, computational modeling, and ERP (event-related potentials) measures were combined. N170 (150–180ms post-stimulus; right hemisphere) and EPN (early posterior negativity; 200–300ms; mainly, right hemisphere) were modulated by expression of whole faces, but not by separate halves. This suggests that expression encoding (N170) and emotional assessment (EPN) require holistic processing, mainly in the right hemisphere. In contrast, the mouth region of happy faces enhanced left temporo-occipital activity (150–180ms), and also the LPC (late positive complex; centro-parietal) activity (350–450ms) earlier than the angry eyes (450–600ms) or other face regions. Relatedly, computational modeling revealed that the mouth region of happy faces was also visually salient by 150ms following stimulus onset. This suggests that analytical or part-based processing of the salient smile occurs early (150–180ms) and lateralized (left), and is subsequently used as a shortcut to identify the expression of happiness (350–450ms). This would account for the happy face advantage in behavioral recognition tasks when the smile is visible. [Copyright &y& Elsevier]

Abstract: Event-related brain potentials (ERPs) were recorded to assess the processing time course of ambiguous facial expressions with a smiling mouth but neutral, fearful, or angry eyes, in comparison with genuinely happy faces (a smile and happy eyes) and non-happy faces (neutral, fearful, or angry mouth and eyes). Participants judged whether the faces looked truly happy or not. Electroencephalographic recordings were made from 64 scalp electrodes to generate ERPs. The neural activation patterns showed early P200 sensitivity (differences between negative and positive or neutral expressions) and EPN sensitivity (differences between positive and neutral expressions) to emotional valence. In contrast, sensitivity to ambiguity (differences between genuine and ambiguous expressions) emerged only in later LPP components. Discrimination of emotional vs. neutral affect occurs between 180 and 430ms from stimulus onset, whereas the detection and resolution of ambiguity takes place between 470 and 720ms. In addition, while blended expressions involving a smile with angry eyes can be identified as not happy in the P200 (175–240ms) component, smiles with fearful or neutral eyes produce the same ERP pattern as genuinely happy faces, thus revealing poor discrimination. [Copyright &y& Elsevier]

We investigated selective attention to emotional scenes in peripheral vision, as a function of adaptive relevance of scene affective content for male and female observers. Pairs of emotional-neutral images appeared peripherally—with perceptual stimulus differences controlled—while viewers were fixating on a different stimulus in central vision. Early selective orienting was assessed by the probability of directing the first fixation towards either scene, and the time until first fixation. Emotional scenes selectively captured covert attention even when they were task-irrelevant, thus revealing involuntary, automatic processing. Sex of observers and specific emotional scene content (e.g., male-to-female-aggression, families and babies, etc.) interactively modulated covert attention, depending on adaptive priorities and goals for each sex, both for pleasant and unpleasant content. The attentional system exhibits domain-specific and sex-specific biases and attunements, probably rooted in evolutionary pressures to enhance reproductive and protective success. Emotional cues selectively capture covert attention based on their bio-social significance. [ABSTRACT FROM AUTHOR]