Is there a brain size-IQ correlation?

Yes, brain size shows a modest positive correlation (r=0.40) with IQ, but size alone does not determine intelligence.

What brain regions matter for IQ?

The prefrontal cortex, anterior cingulate, and parietal regions are consistently associated with reasoning and fluid intelligence.

Yes, white matter integrity correlates with IQ, suggesting efficient neural communication is crucial for cognitive performance.

Limited evidence exists for transferable IQ gains from brain training, though specific skill improvements occur within trained domains.

Peter Kolomiets

|March 25, 2026|Updated Apr 13, 2026|7 min read

Ready to discover your Iq Test?

Deary, I. J., Penke, L., & Johnson, W.. Deary, I. J., Penke, L., & Johnson, W. (2010). The Neuroscience of Human Intelligence
McDaniel, M. A.. McDaniel, M. A. (2005). Big-Brained People Are Smarter: A Meta-Analysis
Jung, R. E. & Haier, R. J.. Jung, R. E. & Haier, R. J. (2013). Brain Imaging and Intelligence

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

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

Peter Kolomiets

|March 25, 2026|Updated Apr 13, 2026|7 min read

Ready to discover your Iq Test?

Deary, I. J., Penke, L., & Johnson, W.. Deary, I. J., Penke, L., & Johnson, W. (2010). The Neuroscience of Human Intelligence
McDaniel, M. A.. McDaniel, M. A. (2005). Big-Brained People Are Smarter: A Meta-Analysis
Jung, R. E. & Haier, R. J.. Jung, R. E. & Haier, R. J. (2013). Brain Imaging and Intelligence