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Brain Size and Socioeconomic Factors

Mar 10, 2025

Lecture Notes: Brain Size and Socioeconomic Status

Introduction

  • Main Question: Who has the bigger brain, Aladdin or Jasmine?
    • The focus is on brain size, specifically the cortical surface area.
    • Cortical surface area relates to the brain's outer layer.
  • Students often relate brain size to experiences and socioeconomic status (SES).

Socioeconomic Status (SES)

  • Components:
    • Income
    • Education level
    • Occupational status
  • SES is linked to brain development.

Study on SES and Brain Surface Area

  • Key Findings:
    • Parental Education: Even one additional year of high school or college is linked to increased brain surface area.
    • Family Income: Strong association with total brain cortical surface area.
    • Strongest correlations in brain areas linked to language and executive functions (temporal lobe, insula, inferior frontal gyrus, right occipital, and medial prefrontal cortex).

Income and Brain Development

  • The association between income and brain surface area is more significant in families with lower income.
    • Greater impact for families earning under $100,000/year, especially under $50,000/year.
    • A $10,000 increase has more impact on lower-income families than on families with higher income.

Graph Explanation

  • The steepest gradient in the graph is where family income is lowest.
  • After about $100,000-$150,000, income differences have less impact on brain surface area.

Examples

  • Comparison of two children:
    • Jasmine ($60,000/year) vs. Aladdin ($50,000/year): $10,000 difference leads to a large difference in brain surface area.
    • Aladdin ($160,000/year) vs. Jasmine ($170,000/year): $10,000 difference has minimal impact.

Additional Findings

  • The income-surface area relationship is consistent across ages and ethnicities.
  • SES should not directly predict brain surface area.
    • Factors like exposure to language also play a role.

Conclusion

  • Overall Findings: SES, particularly income, is positively correlated with cortical brain surface area, especially in families earning under $100,000/year.
  • Implication for Disney Characters: Jasmine may have a larger brain than Aladdin if family wealth is considered.
  • Caution against generalizing findings to all SES situations.

Full transcript