Yes, absolutely. There is a myth that there is no definition or assessment of intelligence precise enough for scientific investigation. For most empirical research studies, intelligence is defined as a general mental ability common to all specific mental abilities. This is the g-factor, first described by Charles Spearman more than 100 years ago. There are other more specific factors as well, including verbal, numerical, and spatial. Some mental abilities are more g-loaded than others but g is pervasive.

IQ tests sample several mental abilities so IQ is a good estimate of g. So is the total SAT score. The g-factor is normally distributed (i.e. the Bell Curve) in the population so where you fall is relative to other people and can be described as a percentile. An IQ sore of 130, for example, is in the top 2 percent of the population. However, IQ points are not like pounds or pints—they are not absolute measures, so caution is required when interpreting changes in IQ or other intelligence test scores. Note that advances in technology usually lead to more precise definitions—think about how the definitions of an atom or a gene have changed with research advances. The same is true for intelligence.

Richard’s first imaging paper with positron emission tomography (PET) in 1988 reported two important observations. First, there were inverse correlations between cerebral glucose metabolic rate and performance on a high g-loaded test of intelligence. This observation was the basis for the brain efficiency hypothesis of intelligence. Second, the brain areas with performance correlations were not localized to the frontal lobe; they were distributed around the brain. Both observations have been the subject of 100s of subsequent research studies. The distributed nature of intelligence in the brain is now well established and more sophisticated studies assess functional and structural connectivity among brain areas and how they relate to intelligence. Brain efficiency has a more complex research history and still is being studied. Modern research relating brain measures to intelligence is detailed in The Neuroscience of Intelligence.

☛ Learn more:

Regional Glucose Metabolic Changes After Learning a Complex Visuospatial/Motor Task: A Positron Emission Tomographic Study (PDF)
- Brain Research

MRI Assessment of Cortical Thickness and Functional Activity Changes in Adolescent Girls Following Three Months of Practice on a Visual-Spatial Task
- BMC Research Notes

A detailed model of relevant brain areas and the neural basis of intelligence was developed with Rex Jung and published in 2007, along with commentaries from other researchers in the field. (This paper was identified by Thomson Reuters Essential Science Indicators as a Fast Breaking Paper in the field of Neuroscience & Behavior, and was one of the most cited papers—upper 1 percent—in its discipline during the subsequent two years). A number of independent papers now support the P-FIT model.