What is the Flynn Effect?

The Flynn Effect describes the observed rise in average IQ scores across decades, discovered by James Flynn in 1987.

Why have IQ scores increased?

Improved nutrition, expanded education, increased cognitive complexity from technology, and reduced childhood infections contribute to rising IQ.

Average IQ has risen approximately 3 points per decade (30 points per century) in developed nations over the last century.

The effect has slowed in wealthy nations in recent decades, possibly due to ceiling effects and declining reading engagement among youth.

Peter Kolomiets

|March 27, 2026|Updated Apr 13, 2026|7 min read

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Flynn, J. R.. Flynn, J. R. (1987). Massive IQ Gains in 14 Nations
Flynn, J. R.. Flynn, J. R. (2007). What Is Intelligence?
Pietschnig, J. & Voracek, M.. Pietschnig, J. & Voracek, M. (2015). One Century of Global IQ Studies

Put what you've learned into practice with these free assessments:

Twin and adoption studies estimate IQ heritability at 50-80%. Genetics creates potential; environment shapes its expression.

Reading strengthens verbal and crystallized intelligence. Early literacy exposure supports IQ development throughout childhood and adolescence.