IQ Research Topic

Flynn Effect and Modern IQ Trends

Many countries showed large IQ-score gains across the 20th century. Recent studies also report slowing or reversals in some cohorts.

Illustrated evolution journey from early hominids to modern humans and digital cognition

What the Flynn Effect Describes

  • Secular score increases over generations on standardized cognitive tests.
  • Typically stronger gains on abstract or nonverbal components.
  • Likely reflects environmental modernization more than rapid genetic change.

Why Some Trends Reversed

  • Recent within-family and cohort studies suggest declines in specific contexts.
  • Researchers discuss education composition, health, media habits, migration, and test renorming effects.
  • Patterns differ by country, birth cohort, and test type.

Practical Interpretation

Compare scores using contemporary norms and local reference groups. Long-term historical comparisons require caution because instruments and populations change.

Primary Sources