The development of emotional face processing during childhood.

Our facial expressions give others the opportunity to access our feelings, and constitute an important nonverbal tool for communication. Many recent studies have investigated emotional perception in adults, and our knowledge of neural processes involved in emotions is increasingly precise. Young children also use faces to express their internal states and perceive emotions in others, but little is known about the neurodevelopment of expression recognition. The goal of the current study was to determine the normal development of facial emotion perception. We recorded ERPs in 82 children 4 to 15 years of age during an implicit processing task with emotional faces. Task and stimuli were the same as those used and validated in an adult study; we focused on the components that showed sensitivity to emotions in adults (P1, N170 and frontal slow wave). An effect of the emotion expressed by faces was seen on the P1 in the youngest children. With increasing age this effect disappeared while an emotional sensitivity emerged on N170. Early emotional processing in young children differed from that observed in the adolescents, who approached adults. In contrast, the later frontal slow wave, although showing typical age effects, was more positive for neutral and happy faces across age groups. Thus, despite the precocious utilization of facial emotions, the neural processing involved in the perception of emotional faces develops in a staggered fashion throughout childhood, with the adult pattern appearing only late in adolescence.