Neural mechanism of facial expression perception in intellectually gifted adolescents

• High IQ group had faster response speed than average IQ group in the facial expression classification task.
• High IQ adolescents elicited faster N170 responses than average adolescents when they classified the inverted faces.
• High IQ group induced larger VPP amplitudes to the sad faces than to the neutral faces.
• High IQ adolescents evoked larger LPP amplitudes than the average IQ group for better attentional control on expressions.

The current study investigated the relationship between general intelligence and the three stages of facial expression processing. Two groups of adolescents with different levels of general intelligence were required to identify three types of facial expressions (happy, sad, and neutral faces), which were presented with either inverted or upright orientation. Participants’ response times and accuracy were measured and event-related potentials (ERPs) were recorded to evaluate neural dynamic processes. The behavioral results showed that high IQ adolescents exhibited shorter response times than average IQ adolescents during the facial expression identification task. The electrophysiological responses showed that no significant IQ-related differences were found for P1 responses during the early visual processing stage. During the middle processing stage, high IQ adolescents had faster structural encoding of inverted faces (shorter N170 latencies) compared to their average IQ peers, and they also showed better structural encoding of sad faces, with larger vertex positive potential (VPP) amplitudes than for neutral faces. During the late processing stage, adolescents with high IQ showed better attentional modulation, with larger late positive potential (LPP) amplitudes compared to adolescents with average IQ. The current study revealed that adolescents with different intellectual levels used different neural dynamic processes during these three stages in the processing of facial expressions.