Genetics and Environment
How heritability works, why genes are not destiny, and what environmental effects researchers measure.
- Polygenic findings
- Heritability interpretation
- Policy relevance
Research Library
IQ Research Hub
A curated overview of major IQ research themes with links to readable topic pages and primary sources.
Education and Lifestyle Factors
What studies show about schooling, sleep, and physical activity in relation to cognitive performance.
- Education effects
- Sleep and cognition
- Exercise and executive function
Flynn Effect and Trend Reversals
Why IQ scores rose across decades in many countries and why some cohorts now show flattening or declines.
- Historical gains
- Within-family evidence
- Environmental explanations
Measurement, Fairness, and Limits
What nonverbal tests capture well, where they can be biased, and why local norms matter.
- Psychometrics
- Cross-cultural norms
- Interpretation boundaries
Health and Life Outcomes
How cognitive scores are associated with long-term health and socioeconomic outcomes in cohort studies.
- Mortality correlations
- Interpretation cautions
- Policy relevance
How to Use These Pages
Start with the topic closest to your question, then review the source list at the bottom of that page.