Overview
This lecture reviews a study on how the brain's sensitivity to race, as measured by amygdala activation, changes from childhood to adolescence, highlighting the role of social environments in shaping neural responses to race.
Background and Rationale
- Adult neuroimaging shows increased amygdala activity when viewing African-American (AA) vs. European-American (EA) faces.
- These neural race biases are hypothesized to be learned, not innate, developing through exposure to cultural norms.
- Children can categorize race early, but explicit and implicit biases evolve with age and social context.
Methods
- 32 healthy youths (ages 4-16.5) from diverse racial backgrounds participated in fMRI scans.
- During scans, participants completed an Emotional Matching Task with AA and EA faces, matched for emotion.
- Parents reported on the racial diversity of children’s peers and neighborhoods.
- fMRI data was analyzed for amygdala activation as a function of age and social diversity.
Key Findings
- Amygdala response to AA (vs. EA) faces does not appear in early childhood but increases throughout adolescence.
- Significant differential amygdala activation to AA faces emerges around age 14.
- This developmental pattern was seen in both AA and EA youth.
- Peer diversity (having more racially diverse friends/schoolmates) independently predicted reduced amygdala response to AA faces.
- Neighborhood diversity did not significantly affect amygdala activation.
- Stronger amygdala response to AA faces was linked to faster behavioral responses to those faces.
Brain Regions Involved
- With age, increased activation to AA faces was found in the amygdala, fusiform gyrus (face perception area), and ventrolateral prefrontal cortex (emotion regulation/evaluation).
- Amygdala response to emotionally salient (angry) faces was stable across all age groups, ensuring observed effects were race-specific.
Implications and Conclusions
- Amygdala sensitivity to race is not innate but emerges in adolescence, likely due to learned cultural knowledge and social experiences.
- Increased racial diversity in peer groups may mitigate neural race biases by reducing the salience of racial categories.
- Interventions increasing cross-race contact could potentially reduce development of implicit race biases.
Key Terms & Definitions
- Amygdala — A brain region involved in processing emotional and socially salient stimuli.
- fMRI (functional Magnetic Resonance Imaging) — A technique to measure brain activity by detecting changes in blood flow.
- Salience — The quality of being particularly noticeable or important.
- Implicit Bias — Unconscious attitudes or stereotypes affecting understanding and behavior.
- Peer Diversity — The racial heterogeneity of a child’s friends and classmates.
Action Items / Next Steps
- Review neural development of social cognition in adolescence.
- Read about interventions for reducing implicit racial bias in youth.
- Complete any assigned readings on the neuroscience of prejudice or amygdala function.