Intelligent People Tend To Have More Efficient Brains
In 1988, Haier and his colleagues scanned volunteers while they attempted to solve problems from the Raven's Advanced Progressive Matrices, a nonverbal intelligence test. The scientists wanted to know which parts of the brain were active as the participants solved the problems. What they discovered was that there was an inverse relationship between brain activation and scores on the intelligence test.
In other words, smarter people had brains that could be more efficient.
Since that landmark study, the field of Neuro-Intelligence has started to take off. From 1988 to 2007, 37 imaging studies of intelligence and reasoning were published. From a 2007 synthesis of the literature, Rex Jung of the University of New Mexico and Haier concluded that intelligence was distributed across the brain and not focused in one part of the frontal lobe.
In Haier's words, "There was a network distributed around the brain that was related to intelligence, which we named the Parieto-Frontal Integration or P-FIT theory. In our theory, not just the specific brain areas are important but how efficiently information is communicated among those areas."
Since that review in 2007, there have now been about 100 new papers on intelligence and imaging. Haier says that this explosion in interest has come largely from cognitive and brain imaging scientists who have grown interested in the brain correlates of IQ tests.
Back in the 1980's there was still some controversy over whether IQ or intelligence tests measured something real. This is because IQ or intelligence has traditionally been assessed using a paper and pencil test. Now that scores on standardized tests have been directly related to brain assessments made by a variety of imaging technologies, Haier says that "brain imaging has just about ended the debate over whether intelligence test scores assess something real-they do."
-- Jonathan Wai
Quoted on Mon Feb 27th, 2012