Brain scans show anxiety impacts boys and girls’ face processing in opposite ways

New research published in Social Cognitive and Affective Neuroscience reveals that boys and girls show distinct brain activity patterns when looking at happy faces, and these patterns are further shaped by how anxious they feel. Specifically, anxious girls showed less brain activity in certain areas when viewing happy faces, while anxious boys showed more activity in the same regions. This suggests that sex and anxiety both play a role in how young people process positive facial expressions.

Understanding how we process facial expressions is important because faces are a primary way we communicate socially. Recognizing emotions in faces helps us navigate social situations and build relationships. Scientists are particularly interested in the brain mechanisms behind this process because difficulties in understanding facial emotions have been linked to various mental health conditions in both adults and children.

While we know that the ability to recognize facial expressions develops throughout childhood and adolescence, less is known about how individual differences, like sex and anxiety, might shape this development at the brain level.

To investigate these questions, researchers conducted a study with 191 children and teenagers aged 6 to 15 years old. All participants were described as typically developing, meaning they did not have any diagnosed psychiatric or neurological conditions. The researchers recruited participants through community flyers, local events, and online advertisements.

Before the study, parents completed a questionnaire called the Behavior Assessment System for Children, Third Edition. This questionnaire helped assess the children’s anxiety levels based on parental observations of their behavior. Specifically, the researchers focused on the anxiety subscale of this questionnaire, which provides a standardized score reflecting the level of anxiety symptoms a child is experiencing.

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During the study, each child underwent brain scanning using a technique called functional magnetic resonance imaging. This method allows scientists to observe brain activity by measuring changes in blood flow. While in the scanner, the children participated in a task involving facial expressions. They were shown images of faces displaying three different emotions: angry, happy, and neutral.

Importantly, the task was designed to be implicit, meaning the children were not explicitly asked to focus on the emotions. Instead, they were instructed to indicate whether each face was male or female by pressing a button. This indirect approach to studying emotion processing is known to sometimes elicit stronger brain responses compared to directly asking participants to judge emotions.

The faces used in the study were carefully selected from a validated set of images that included diverse racial and ethnic backgrounds. For each emotion type, the researchers used the same identities across different expressions, ensuring that the only thing changing was the emotion displayed, not the person’s identity. During the task, each face was shown briefly, followed by a short break. The researchers recorded both how quickly and accurately the children could identify the sex of the faces, and also measured their brain activity while they were viewing the different expressions.

After collecting the brain scan data, the researchers used sophisticated computer programs to analyze the images. They corrected for head movements during scanning and standardized the brain images to allow for comparisons across individuals. Then, they used a statistical method to examine how brain activity differed when participants viewed angry, happy, and neutral faces. The researchers were particularly interested in understanding how sex and anxiety levels influenced these brain responses, while also taking into account the children’s ages.

The study revealed several interesting findings. First, when comparing brain responses to angry faces versus neutral faces, the researchers observed increased activity in a specific area of the brain called the right fusiform gyrus. This region is known to be involved in face processing, and its activation to angry faces suggests it plays a role in recognizing and responding to emotionally expressive faces. However, the study did not find a similar overall increase in brain activity when comparing happy faces to neutral faces across all participants.

The most striking finding was related to the interaction between sex and anxiety when viewing happy faces. The analysis revealed that in a network of brain regions involved in visual processing and memory, girls with higher anxiety scores showed reduced brain activity when viewing happy faces compared to neutral faces.

Conversely, boys with higher anxiety scores showed increased brain activity in the same brain network when viewing happy faces compared to neutral faces. This means that anxiety seems to have opposite effects on brain responses to happy faces in boys and girls. This interaction was observed in brain areas including regions in the back of the head involved in vision, parts of the temporal lobe associated with memory, and areas in the parietal lobe involved in spatial awareness.

While the study provides valuable insights, it is important to consider its limitations. The researchers only examined three basic facial expressions. Future studies could explore a wider range of emotions, including more complex ones. Additionally, the task was designed to implicitly measure emotion processing, and it did not directly assess how well children recognized the emotions.

The study also did not find the expected activity in the amygdala, a brain region often associated with emotion processing, which is sometimes observed in adult studies of facial expressions. However, other research suggests that the amygdala’s response to facial expressions may develop later in childhood and adolescence. Finally, anxiety levels were assessed based on parental reports, which may not perfectly reflect the children’s own experiences of anxiety.

Future research could build upon these findings by using self-report measures of anxiety from the children themselves, and by examining children with clinically diagnosed anxiety disorders to see if these patterns are even more pronounced. It would also be beneficial to investigate how these brain responses change as children develop, potentially by following the same children over time.

Future studies could also explore the role of puberty and hormonal changes in shaping the relationship between anxiety, sex, and facial emotion processing. Examining more complex interactions, such as how age, sex, and anxiety together influence brain responses to facial expressions, could also provide a richer understanding of this important aspect of social development.

The study, “Anxiety symptoms are differentially associated with facial expression processing in boys and girls,” was authored by Gaelle E. Doucet, Jordanna A. Kruse, Ahrianna Keefe, Danielle L. Rice, Anna T. Coutant, Haley Pulliam, OgheneTejiri V. Smith, Vince D. Calhoun, Julia M. Stephen, Yu-Ping Wang, Stuart F. White, Giorgia Picci, Brittany K. Taylor, and Tony W. Wilson.