Researchers challenge Brain Myth #3.

In Brain General Structure and Function, Brain Science by Brainy Days Ahead

Now that we have brain imaging methods (e.g., MRI, PET), reliable assessments of brain volume and investigations of its association with IQ are now possible. These researchers find a weak association that is of little practical relevance between brain volume and IQ test performance in humans. The research shows that brain structure and integrity appear to be more important as a biological foundation of IQ. It’s not overturned yet.