CHC Theory
Encyclopedia
Recent advances in current theory and research on the structure of human
Human
Humans are the only living species in the Homo genus...

 cognitive abilities have resulted in a new empirically derived model commonly referred to as the Cattell–Horn–Carroll theory of cognitive abilities (CHC theory). CHC theory of cognitive abilities is an amalgamation of two similar theories about the content and structure of human cognitive abilities. The first of these two theories is Gf-Gc
Fluid and crystallized intelligence
In psychology, fluid and crystallized intelligence are factors of general intelligence originally identified by Raymond Cattell...

 theory (Raymond Cattell
Raymond Cattell
Raymond Bernard Cattell was a British and American psychologist, known for his exploration of many areas in psychology...

, 1941; Horn 1965), and the second is John Bissell Carroll
John Bissell Carroll
John Bissell Carroll was an American psychologist known for his contributions to psychology, educational linguistics and psychometrics.- Early years :...

's (1993) Three-Stratum theory
Three Stratum Theory
In 1993 John Carroll published "Human cognitive abilities: A survey of factor-analytic studies", which outlined his hierarchical, Three-Stratum Theory of cognitive abilities....

. Carroll's expansion of Gf-Gc theory to CHC theory was developed in the course of a major survey of research over the past 60 or 70 years on the nature, identification, and structure of human cognitive abilities. That research involved the use of the mathematical technique known as factor analysis
Factor analysis
Factor analysis is a statistical method used to describe variability among observed, correlated variables in terms of a potentially lower number of unobserved, uncorrelated variables called factors. In other words, it is possible, for example, that variations in three or four observed variables...

. In comparison to other well-known theories of intelligence and cognitive abilities, CHC theory is the most comprehensive and empirically supported psychometric theory of the structure of cognitive and academic abilities.

The CHC model was expanded by McGrew (1997) and later revised with the help of Flanagan (1998). There are a fairly large number of distinct individual differences in cognitive ability, and CHC theory holds that the relationships among them can be derived by classifying them into three different strata: stratum I, "narrow" abilities; stratum II, "broad abilities"; and stratum III, consisting of a single "general" ability.

CHC theory abilities

There are 10 broad stratum abilities and over 70 narrow abilities below these.
The broad abilities are
  • 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.
  • Fluid Intelligence (Gf): includes the broad ability to reason, form concepts, and solve problems using unfamiliar information or novel procedures.
  • Quantitative Reasoning (Gq): is 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).


(G) from Carroll's model has been omitted, but fluid and crystallized intelligence from the Cattell-Horn model remained. Please refer to Flanagan et al. (2005) for a description on narrow abilities.

CHC model tests

Many tests of cognitive ability have been classified using the CHC model and are described in The Intelligence Test Desk Reference (ITDR) (McGrew & Flanagan, 1998). CHC theory is particularly relevant to school psychologists
School psychology
School psychology is a field that applies principles of clinical psychology and educational psychology to the diagnosis and treatment of children's and adolescents' behavioral and learning problems...

 for psychoeducational assessment. 5 of the 7 major tests of intelligence have changed to incorporate CHC theory as their foundation for specifying and operationalizing cognitive abilities/processes. Since even all modern intellectual test instruments fail to effectively measure all 10 broad stratum abilities an alternative method of cognitive assessment and interpretation called Cross Battery Assessment
Cross Battery Assessment
Cross-battery assessment approach was first introduced in the late 1990s by Dawn Flanagan, Samuel Ortiz, and Kevin McGrew. It offers practitioners the means to make systematic, valid, and up-to-date interpretations of intelligence batteries and augment them with other tests in a way that is...

(XBA; Flanagan, Ortiz, Alfonso, & Dynda, 2008) was developed.

Recently (March 11th, 2009) McGrew released a draft of the revised broad and narrow ability definitions.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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