Face perception

Face perception is an individual's understanding and interpretation of the face, particularly the human face, especially in relation to the associated information processing in the brain.

The proportions and expressions of the human face are important to identify origin, emotional tendencies, health qualities, and some social information. From birth, faces are important in the individual's social interaction. Face perceptions are very complex as the recognition of facial expressions involves extensive and diverse areas in the brain. Sometimes, damaged parts of the brain can cause specific impairments in understanding faces or prosopagnosia.

From birth, infants possess rudimentary facial processing capacities. Infants as young as two days of age are capable of mimicking the facial expressions of an adult, displaying their capacity to note details like mouth and eye shape as well as to move their own muscles in a way that produces similar patterns in their faces. However, despite this ability, newborns are not yet aware of the emotional content encoded within facial expressions. Five-month-olds, when presented with an image of a person making a fearful expression and a person making a happy expression, pay the same amount of attention to and exhibit similar event-related potentials (ERPs) for both. However, when seven-month-olds are given the same treatment, they focus more on the fearful face, and their event-related potential for the scared face shows a stronger initial negative central component than that for the happy face. This result indicates an increased attentional and cognitive focus toward fear that reflects the threat-salient nature of the emotion. In addition, infants' negative central components were not different for new faces that varied in the intensity of an emotional expression but portrayed the same emotion as a face they had been habituated to but were stronger for different-emotion faces, showing that seven-month-olds regarded happy and sad faces as distinct emotive categories. While seven-month-olds have been found to focus more on fearful faces, another study by Jessen, Altvater-Mackensen, and Grossmann found that "happy expressions elicit enhanced sympathetic arousal in infants" both when facial expressions were presented subliminally and when they were presented supraliminally, or in a way that the infants were consciously aware of the stimulus. These results show that conscious awareness of a stimulus are not connected to an infant's reaction to that stimulus.

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