Phased processing of facial emotion: an ERP study

We examined the temporal characteristics of facial-emotion processing. The stimuli were several morphed images containing seven facial emotions (neutral, anger, happiness, disgust, sadness, surprise, and fear) and ten-graded intensity levels to parametrically control these aspects of facial emotions. Brain activity was recorded with electroencephalography as the subjects detected the facial emotion and assessed its intensity. We found that the temporal profile of detection was quite different from the assessment of intensity. A positive component 100 ms after stimulus onset (P100) was significantly correlated with the correct detection of facial emotion, whereas a negative component 170 ms after stimulus onset (N170) was significantly correlated with the assessment of intensity level. The source of both the P100 and N170 signals was consistently localized to the right occipito-parietal region. We propose phased processing of facial emotion, in which rapid detection of any facial emotion occurs within 100 ms and detailed processing, including the assessment of the intensity, occurs shortly afterwards.