Editing Human intelligence (section)

=== Cattell–Horn–Carroll theory ===
{{Main|Cattell–Horn–Carroll theory}}

Many of the broad, recent IQ tests have been greatly influenced by the [[Cattell–Horn–Carroll theory]]. It is argued to reflect much of what is known about intelligence from research. A hierarchy of factors for human intelligence is used. ''g'' is at the top. Under it there are 10 broad abilities that in turn are subdivided into 70 narrow abilities. The broad abilities are:<ref name=Kaufman2009>IQ Testing 101, Alan S. Kaufman, 2009, Springer Publishing Company, {{ISBN|978-0-8261-0629-2}}</ref>
*Fluid intelligence (Gf): includes the broad ability to reason, form concepts, and solve problems using unfamiliar information or novel procedures.
*Crystallized intelligence (Gc): includes the breadth and depth of a person's acquired knowledge, the ability to communicate one's knowledge, and the ability to reason using previously learned experiences or procedures.
*Quantitative reasoning (Gq): the ability to comprehend quantitative concepts and relationships and to manipulate numerical symbols.
*Reading & writing ability (Grw): includes basic reading and writing skills.
*Short-term memory (Gsm): is the ability to apprehend and hold information in immediate awareness and then use it within a few seconds.
*Long-term storage and retrieval (Glr): is the ability to store information and fluently retrieve it later in the process of thinking.
*Visual processing (Gv): is the ability to perceive, analyze, synthesize, and think with visual patterns, including the ability to store and recall visual representations.
*Auditory processing (Ga): is the ability to analyze, synthesize, and discriminate auditory stimuli, including the ability to process and discriminate speech sounds that may be presented under distorted conditions.
*Processing speed (Gs): is the ability to perform automatic cognitive tasks, particularly when measured under pressure to maintain focused attention.
*Decision/reaction time/speed (Gt): reflect the immediacy with which an individual can react to stimuli or a task (typically measured in seconds or fractions of seconds; not to be confused with Gs, which typically is measured in intervals of 2–3 minutes). See [[Mental chronometry]].
Modern tests do not necessarily measure of all of these broad abilities. For example, Gq and Grw may be seen as measures of school achievement and not IQ.<ref name=Kaufman2009/> Gt may be difficult to measure without special equipment.

''g'' was earlier often subdivided into only Gf and Gc which were thought to correspond to the nonverbal or performance subtests and verbal subtests in earlier versions of the popular Wechsler IQ test. More recent research has shown the situation to be more complex.<ref name=Kaufman2009/>