Glossary
General intelligence (g)
Definition
General intelligence, written g, is the shared ability that shows up across many different mental tests. People who do well on one kind of test, such as matrices, tend to do well on others, such as vocabulary or arithmetic. Charles Spearman proposed g in 1904 to explain that overlap.
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Why it matters for IQ scores
Charles Spearman proposed the general intelligence factor in 1904 (Wikipedia: g factor). The idea explains why a single IQ number is useful at all: if abilities were completely separate, adding them into one score would make little sense. Because performance on different kinds of puzzles tends to go together, one summary score can say something about all of them at once.
An example
On the IQ Octopus test, someone who solves the harder matrix puzzles quickly will often do well on the number series too, though not always. The overlap is what g describes. The differences, such as being stronger at spatial items than at number items, are what a section breakdown shows.
Common confusions
g is not a thing you can point to in the brain, and it is not the whole of intelligence. It is a pattern in test data. It is also not the same as fluid intelligence or crystallized intelligence, which are narrower abilities. For the full story, read what is the g factor? and see how tests are built in psychometrics.
The layers below g
John Carroll's 1993 reanalysis of more than 460 data sets produced a three-stratum model with general ability at the top (Carroll, 1993). Today's Cattell-Horn-Carroll (CHC) family of theories places broad abilities such as fluid reasoning, comprehension-knowledge, visual processing, working memory and processing speed under g (McGrew et al., 2023). See CHC theory and theories of intelligence.
Try one · Logical Reasoning
Which tile completes the second pair?
Tap the option you think is right, or show the answer.
Show the answer
The missing panel shows a small solid circle, with small solid shapes: a triangle at the bottom (option 1).
How to solve it
- Compare the first two panels and name exactly what changed.
- The main shape and the small shapes swap forms: the main shape takes the form of the small ones, and the small ones take the form of the main shape.
- Nothing else changes.
- Apply the same change to the third panel: a small solid triangle pointing up, with small solid shapes: a circle at the bottom.
- So the missing panel shows a small solid circle, with small solid shapes: a triangle at the bottom.
That was 1 puzzle. The full test has 25.
Sources
- g factor (psychometrics). Wikipedia. en.wikipedia.org/wiki/G_factor_(psychometrics)
- Carroll, J. B. (1993). Human cognitive abilities: A survey of factor-analytic studies. Cambridge University Press. doi.org/10.1017/CBO9780511571312
- McGrew, K. S., Schneider, W. J., Decker, S. L., & Bulut, O. (2023). A psychometric network analysis of CHC intelligence measures. Journal of Intelligence, 11(1), 19. doi.org/10.3390/jintelligence11010019