What is IQ heritability?

Heritability estimates suggest 50-80% of IQ variation within populations is attributable to genetic differences, depending on the population studied.

Does high heritability mean IQ is fixed?

No. High heritability describes variation in a specific population, not individual potential. Environment significantly influences IQ development.

Identical twins reared apart show IQ correlations of 0.70+, suggesting strong genetic influence, but environmental factors remain crucial.

Genes set a range of potential; education, nutrition, socioeconomic status, and experiences determine where within that range IQ develops.

Peter Kolomiets

|March 26, 2026|Updated Apr 13, 2026|8 min read

Ready to discover your Iq Test?

Plomin, R., et al.. Plomin, R., DeFries, J. C., Knopik, V. S., & Neiderhiser, J. M. (2016). Top 10 Replicated Findings from Behavioral Genetics
Jensen, A. R.. Jensen, A. R. (1998). The g Factor: The Science of Mental Ability
Scarr, S. & Weinberg, R. A.. Scarr, S. & Weinberg, R. A. (1978). Intellectual Similarities Within Families

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IQ scores have increased 30 points per century, driven by better nutrition, education, and cognitive complexity.

The g factor represents general intelligence underlying all cognitive abilities. It explains why people who excel in one domain often excel broadly.

Peter Kolomiets

|March 26, 2026|Updated Apr 13, 2026|8 min read

Ready to discover your Iq Test?

Plomin, R., et al.. Plomin, R., DeFries, J. C., Knopik, V. S., & Neiderhiser, J. M. (2016). Top 10 Replicated Findings from Behavioral Genetics
Jensen, A. R.. Jensen, A. R. (1998). The g Factor: The Science of Mental Ability
Scarr, S. & Weinberg, R. A.. Scarr, S. & Weinberg, R. A. (1978). Intellectual Similarities Within Families