The g factor is the general tendency across cognitive tasks
The g factor is a concept that describes the general tendency shared across multiple cognitive tasks, such as vocabulary, reasoning, memory, and processing speed. Even when tasks look different on the surface, their scores often show positive correlations. The idea of g is used to explain that common part.
The g factor is a theoretical concept, while FSIQ is an overall score that summarizes it in test results. In intelligence tests such as the WAIS, multiple subtests are combined into FSIQ, or Full Scale IQ. This can be read as a score close to the g estimated from the whole test.
FSIQ is an entry point, not the endpoint
FSIQ is useful for getting a short view of the overall level. It helps show whether the result is around average, higher, or lower.
However, FSIQ combines differences across domains into one number. A person with high verbal comprehension and low processing speed may appear to have a middle-range overall score. In that case, FSIQ alone can make it harder to see which domains are strong and where load is more likely to increase.
The g factor and FSIQ are entry points for seeing the whole picture. To connect results to real situations, it is necessary to look at differences across domains as well.
FSIQ is covered in more detail in What is FSIQ?.
CHC theory reads intelligence in three layers
CHC theory understands intelligence in three layers.
- Third stratum: the g factor, the general tendency shared across tasks
- Second stratum: broad abilities such as Gc, Gf, Gv, Gwm, and Gs
- First stratum: specific abilities such as vocabulary, inductive reasoning, and mental rotation
Overall IQ can be too broad, while individual subtests can be too narrow. Looking at the second stratum in between makes the meaning of the result easier to organize.
For example, even with the same FSIQ, a person with higher Gc and lower Gs and a person with higher Gf and lower Gwm may have different strengths and different conditions that create load. After looking at g, reading the balance across the five domains makes the result easier to understand as a cognitive profile.
Reading it in BrainTypeIQ
BrainTypeIQ is an online IQ test with 9 tasks that shows overall IQ and differences across the cognitive profile. It is structured to separate the five domains of Gc, Gf, Gv, Gwm, and Gs, rather than showing only overall IQ.
It is not a substitute for a diagnostic assessment, but it can be an entry point for separating the overall level from the balance across domains.