Nov 20, 2025·Special Population & Related Conditions
Is IQ Genetic?
Is IQ genetic? Yes—about 50-60% heritable, but environment also shapes it. Discover what determines your IQ: genes, education, and more.
One of the most persistent questions in psychology is whether intelligence is genetic. The short answer is yes, but that's far from the whole story. Intelligence is influenced by both genes and environment, and understanding how they interact is more nuanced than most people realize.
Behavioral geneticists measure genetic influence through a statistic called "heritability," which ranges from 0 to 1 (or 0% to 100%). Heritability tells us what proportion of the differences in IQ scores within a population can be attributed to genetic differences between people. Critically, it does not reveal how much of an individual person's IQ comes from their genes.
The heritability of IQ is not a fixed number. It varies depending on the population studied and the environment. In non-neglectful environments in wealthy countries, the heritability of IQ tends to average about .50 to .60 (50-60%). Interestingly, heritability for IQ is higher in adults than in young children, suggesting that genetic influences on intelligence become more apparent as people age and create environments that match their genetic predispositions.
Within the United States, heritability does not vary across the largest racial and ethnic groups, nor does it seem to vary consistently across socioeconomic groups, at least in environments that aren't extremely deprived.
What Heritability Actually Means
Heritability is one of the most misunderstood concepts in genetics. Consider two extreme examples: If a population of clones took an IQ test, heritability would be 0% because there are no genetic differences to cause IQ score differences. Conversely, if every person had an identical environment, heritability would be 100% because only genetic differences could explain IQ variations.
This reveals something important: heritability describes differences between people in a specific population and environment, not the origins of an individual's traits. Saying that IQ is 60% heritable does not mean that 60% of a person’s IQ comes from their parents' DNA and 40% comes from their environment. Both genes and environment are necessary for any trait to develop. Without genes, there's no blueprint; without environment, that blueprint cannot be expressed.
Perhaps most importantly, high heritability does not mean a trait cannot be changed. Height is highly heritable, yet average height increased in many countries during the 20th century due to improved nutrition. Similarly, IQ scores have risen over time through what's known as the Flynn effect, despite IQ's substantial heritability.
Specific Genes for Intelligence
While heritability studies show that genes matter, heritability statistics don’t identify which specific genes are involved. That's where molecular genetics comes in. The search for these genes has been remarkably successful. Currently, there are hundreds of known genetic variants associated with differences in IQ. Researchers can combine these variants to create "polygenic scores" that predict IQ with modest accuracy, and these predictions should improve as genetic datasets expand and methodologies improve.
Take our professional IQ test
Want to know your IQ? Try the first ever professional online IQ test.
Article Categories
All ArticlesUnderstanding IQ ScoresTaking an IQ TestRIOT-Specific InformationGeneral IQ & IntelligenceAdvanced Topics & ResearchIQ Scores & InterpretationMensa & High-IQ SocietiesOnline IQ Tests IQ Test Basics & FundamentalsAverage IQ & DemographicsFamous People & IQHistory & Origins Of IQ TestingAccuracy, Reliability & CriticismSpecial Population & Related ConditionsImproving IQ / PreparationSpecific IQ Tests & FormatsIQ Testing for HR & RecruitmentSkills Assessment
Related Articles
Take our IQ testsCompare all tests
Basic IQ Test
5 subtests + 5 cognitive abilities
Features
- ~13 Minutes
- IQ score
- Cognitive abilities breakdown
- ±5.6 IQ margin of error
5/15 Subtests
Learn moreVocabulary
Matrix Reasoning
SToVeS
Visual Reversal
Symbol Search
Full IQ Test
15 subtests + all cognitive abilities
Features
- ~52 Minutes
- IQ score
- Cognitive abilities breakdown
- ±3.7 IQ margin of error
15/15 Subtests
Learn moreVocabulary, Information, Analogies
Matrix Reasoning, Visual Puzzles, Figure Weights
Object Rotation, SToVeS, Spatial Orientation
Computation Span, Exposure Memory, Visual Reversal
Symbol Search, Abstract Matching
Simple Reaction Time, Choice Reaction Time
Community
Intelligence Journals & Organizations
News & Press
Our Articles
Our Articles
Our Articles
Our Articles
Our Articles