The distinct abilities an IQ score is built from — reasoning, memory, speed, verbal and spatial ability — and what each one measures.
9 articles
Numerical reasoning means reasoning with numbers and mathematical relations — which CHC treats as a narrow ability under fluid reasoning, distinct from acquired quantitative knowledge. What the distinction means and what a short test can sample.
An IQ score is a summary of several distinct abilities. What the broad abilities are, how they relate to general intelligence, and how much the separate scores really tell you.
Pattern recognition is the core of non-verbal reasoning tests. How matrix items are built, the rules they use, the mistakes people make — and nine worked examples.
Working memory holds and manipulates information for seconds at a time. Its real capacity is about four chunks — not seven — it correlates with fluid intelligence at r ≈ .72, and it forms one of the four index scores behind your WAIS IQ.
Fluid intelligence solves novel problems; crystallized intelligence applies what you know. Why one declines with age and the other keeps rising into your sixties.
Inhibition, working memory and cognitive flexibility. The unity-and-diversity framework, the task impurity problem, and why lab tasks and rating scales correlate at only .19.
Processing speed peaks before any other cognitive ability. Salthouse's theory of cognitive ageing, inspection time and IQ, and why a low speed score is not a low ability.
Spatial ability predicts STEM achievement beyond maths and verbal — and no admissions test measures it. The 217-study meta-analysis showing it can be trained.
Verbal ability rises into your sixties, and is stable enough that clinicians use vocabulary to estimate the IQ you had before an illness. Plus where that method fails.
