As children grow, their brains develop distinct ways of processing facial expressions based on a mix of emotion and face gender. A recent study reveals that these neural responses grow more specialized with age, while elevated anxiety can alter how kids react to potentially threatening faces. The research was published in Developmental Cognitive Neuroscience.
Cultural norms and early experiences teach children to associate certain emotions with specific genders. Anger is often linked with male faces and interpreted as a sign of dominance or potential threat. In contrast, happiness is frequently associated with female faces and perceived as a sign of emotional warmth. When a facial expression violates these expectations, such as an angry female face or a happy male face, the brain must work harder to interpret the social cue.
The research team wanted to see how the developing brain manages these unexpected social signals. They focused on tracking specific patterns of electrical activity, known as brain waves. Alpha and beta brain waves are associated with attention and the filtering of sensory information. Gamma waves, which oscillate much faster, are linked to higher cognitive tasks, like blending different pieces of social and emotional information together.
The scientists also aimed to explore how anxiety affects these developmental trajectories. Anxious individuals often exhibit a specific pattern of attention when faced with a threat. They may initially focus heavily on a threatening cue before quickly looking away to reduce their own psychological distress. The research team, led by neuroscientists Hua Bai, Yasra Arif, and Tony W. Wilson at Boys Town National Research Hospital in Nebraska, set out to map these cognitive processes in youth.
The researchers enrolled a group of healthy children and teenagers between the ages of six and 17. The final analysis included data from 149 participants. While positioned inside a brain scanning machine, the participants viewed photographs of adult faces displaying angry, happy, or neutral expressions. Half of the faces shown in the experiment were male, and the other half were female.
The participants were instructed to press a button indicating the gender of each face, regardless of the emotional expression. While the youths performed this task, the researchers recorded their neural activity using a technique called magnetoencephalography. This non-invasive imaging technology measures the tiny magnetic fields produced by the electrical firing of brain cells, allowing researchers to track brain waves with high precision in real time.
The team also collected behavioral data during the task, such as how accurately and quickly the participants responded. Afterward, the researchers used specialized software to filter out background noise from the brain recordings, such as the electrical signals generated by eye blinks and heartbeats. Finally, the children aged eight and older completed a standardized self-report questionnaire to assess their daily anxiety levels.
The behavioral results indicated that response times varied depending on both the age of the participant and the combination of gender and emotion. The youths responded fastest to angry male faces. In contrast, angry female faces prompted the slowest reactions across the board. The researchers noted that these reaction times did not reach a level of statistical significance for the happy faces, meaning the age-related changes were specific to angry and neutral expressions.
When analyzing the brain wave data, the researchers noticed distinct patterns emerging within a fraction of a second. In regions of the brain responsible for visual perception and movement control, alpha and beta wave responses grew stronger in older children. These brain waves were especially active when participants viewed faces that violated social expectations, such as angry female faces and happy male faces.
The researchers found a specific association between these brain waves and reaction times for angry male faces. Older children showed increased alpha and beta activity in a brain region involved in motor planning and inhibitory control. The scientists proposed that as children age, they increasingly recruit this inhibitory network to control their physical responses to threatening cues, slowing themselves down just enough to process the information safely.
A different pattern emerged slightly later in the brain’s processing timeline, characterized by gamma wave activity. Older children displayed increased gamma activity in areas of the brain known for handling complex social and emotional information, such as the temporoparietal junction. This activity was particularly elevated when processing angry female faces, suggesting that the brain requires more integrative processing to make sense of unexpected social signals.
The team also observed age-related increases in gamma waves when participants viewed neutral faces. However, these responses were mixed, with some brain regions reacting more to neutral male faces and others to neutral female faces. The researchers attributed this lack of a consistent pattern to the inherently ambiguous nature of a neutral expression, which requires social interpretation regardless of the person’s gender.
Individual anxiety levels also altered how the brain processed these faces. Children reporting higher levels of anxiety displayed weaker early alpha and beta responses in visual processing areas when viewing angry male faces. This pattern aligns with behavioral theories suggesting that anxious youths instinctively suppress attention toward highly threatening social cues to manage their own distress. Meanwhile, responses to angry female faces remained consistently elevated across all anxiety levels.
The study focuses exclusively on typically developing children, meaning the results may not generalize to youths with clinical conditions like social anxiety disorder or autism spectrum disorder. The faces used in the experiment were also entirely composed of adults. Future studies could incorporate images of children and teenagers to test if youth react differently to the faces of their own peers.
The participant pool was predominantly White, which introduces the possibility of an own-race familiarity bias in how the faces were perceived. Because the study only evaluated participants at a single point in time, researchers cannot track how these brain patterns evolve within the same individual over the years. Longitudinal tracking would clarify how early brain responses shape social and emotional development long-term.
The study, “Facial expression processing is modulated by face gender and anxiety levels in developing youth,” was authored by 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.