A new study from Boys Town National Research Hospital in Nebraska shows that children’s brains processing facial expressions become more specialised with age, and that elevated anxiety can alter reactions to faces displaying potential threat. The research, conducted by Hua Bai, Yasra Arif and Tony W. Wilson among others, examined how emotion and face gender interact in the developing brain and behavioural responses in youths aged six to 17, with data from 149 participants.
Researchers note that cultural norms and early experiences shape how children interpret emotions on different faces. Anger is often linked with male faces and interpreted as a sign of dominance or threat, while happiness is more commonly associated with female faces as a sign of warmth. When a facial expression defies these expectations, the brain must work harder to decode the social cue.
The team set out to map the brain’s fast, automatic processing of such signals by monitoring brain activity in real time. They focused on brain waves linked to attention and information processing: alpha and beta waves reflect sensory filtering and processing, while gamma waves are tied to higher-level integration of social and emotional information.
In addition to tracking neural activity, the researchers investigated how anxiety might influence these developmental trajectories. It is known that anxious individuals can exhibit a rapid, initial focus on threat before diverting attention to reduce distress. The study therefore aimed to chart how anxiety shapes the way youths process faces with varying gender and emotion.
Participants—healthy children and teenagers aged six to 17—were placed in a brain scanner and shown photographs of adult faces expressing angry, happy, or neutral emotions. Half of the faces were male and half were female. The youths were asked to indicate the gender of each face, regardless of the expression, while their brain activity was recorded using magnetoencephalography, a non-invasive technique that measures the magnetic fields generated by neural activity.
Behaviorally, responses varied with age and the combination of gender and emotion. Participants responded fastest to angry male faces and slowest to angry female faces, while there was no statistically significant difference in response times for happy faces across ages. These findings suggest that the processing of threat-related cues differs by gender and matures at different rates.
Examining the brain data revealed early and age-related changes in neural processing. In regions involved in visual perception and motor control, alpha and beta wave activity grew stronger with age, particularly when faces violated social expectations—such as angry female faces or happy male faces. For angry male faces, older children showed heightened alpha and beta activity in brain areas tied to motor planning and inhibitory control, implying that they increasingly recruit this network to temper physical responses and process threatening cues more carefully.
A slightly later wave of processing showed elevated gamma activity in regions associated with complex social and emotional processing, notably the temporoparietal junction. This pattern was pronounced when youths viewed angry female faces, indicating greater integrative processing was required to interpret these unexpected signals.
Age-related gamma increases were also observed for neutral faces, though the pattern varied by brain region and the expression’s ambiguity, with some areas responding more to neutral male faces and others to neutral female faces. The researchers attributed the mixed results to the inherently ambiguous nature of neutrality in social interpretation.
Anxiety level added another layer of nuance. Youths reporting higher anxiety displayed weaker early alpha and beta responses in visual processing areas when viewing angry male faces, aligning with theories that anxious individuals may suppress attention to highly threatening cues to manage distress. In contrast, responses to angry female faces remained elevated across anxiety levels, suggesting a robust sensitivity to this particular threat cue regardless of anxiety.
The study authors emphasised that the findings relate to typically developing children. The researchers caution that results may not generalise to youths with conditions such as social anxiety or autism spectrum disorder. Limitations noted include the use of adult faces, a predominantly White participant pool, and the cross-sectional design, which cannot track how brain patterns evolve within individuals over time.
The paper, titled Facial expression processing is modulated by face gender and anxiety levels in developing youth, lists Hua Bai, Yasra Arif, Jake J. Son, Nathan M. Petro, Grace C. Ende, Danielle L. Rice, Jason A. John, Anna T. Coutant, Erica L. Steiner, Ryan J. Glesinger, Hannah J. Okelberry, Brittany K. Taylor, Giorgia Picci and Tony W. Wilson as authors.
