Abstract

Rapid accurate categorization of the emotional state of our peers is of critical importance to human social functioning. Most studies however focus primarily on the processing of select facial expressions of emotion in isolation (e.g. fear), leaving unresolved the question of how facial expressions are processed in more challenging ‘which expression’ tasks. Here I will present results from two studies, one that seeks to establish the time course of processing of three facial expressions of emotion (fearful, disgusted, and happy) during objectively unaware and aware perception. Although participant’s behavioral responses did not differentiate between the emotional content of the stimuli in the unaware condition activity over frontal and occipitotemporal (OT) brain regions did. Furthermore the nature of this neuronal response differed as a function of later categorization of the emotional content of the stimuli (hits, false alarms, correct rejections and misses). In a second series of experiments, I tested if observers make use of different visual information from expressive faces depending on the nature of the categorization task. Specifically I determined the facial features crucial for the categorization of three key facial expressions of emotion (fear, disgust and anger) during ‘expressive or neutral‘ and ‘which expression’ categorization tasks. Rather than always using the same visual information to process the same emotional categories, I found that observers adapt their information use to target the most useful visual information. Taken together these results provide novel insight into the processing of facial expressions of emotion and critically also highlight the importance of considering the specifics of the categorization task asked of participants and their eventual categorization response.