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Distributed brain sites for the g-factor of intelligence
Roberto Colom1, Rex E Jung, Richard J Haier
1Facultad de Psicología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Neuroimage
|March 4, 2006
Summary
The general factor of intelligence (g) is linked to greater gray matter volume across the entire brain. This suggests intelligence is a distributed brain function, not confined to the frontal lobes.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Psychometrics
Background:
- The general factor of intelligence (g) is an empirically observed phenomenon where most cognitive tests correlate positively.
- Individual cognitive tests vary in their involvement of the general factor of intelligence (g).
Purpose of the Study:
- To investigate the relationship between regional brain volumes and the general factor of intelligence (g).
- To determine if g is associated with specific brain regions or distributed across the brain.
Main Methods:
- Structural magnetic resonance imaging (MRI) was used to assess regional brain volumes.
- Voxel-based morphometry (VBM) was employed to correlate gray matter volumes with cognitive test performance.
- Eight cognitive tests with varying degrees of g-involvement were administered.
Main Results:
- A positive correlation was found between the g-involvement of cognitive tests and gray matter volume across the entire brain.
- Measures of verbal and non-verbal intelligence (vocabulary and block design) correlated with gray matter volume in frontal, parietal, temporal, and occipital lobes.
Conclusions:
- The general factor of intelligence (g) is associated with widespread gray matter volumes throughout the brain.
- Intelligence (g) appears to be a distributed brain function, challenging theories of exclusive frontal lobe origin.