Intelligence Quotient

What is IQ?

IQ, often referred to in intelligence tests as Full Scale IQ, is thought to represent general intelligence (or g) and be comprised of multiple index scores (or factors), such as the following: visual–spatial (evaluating and integrating visual–spatial information), verbal comprehension (vocabulary, understanding of complex verbal information, and verbal reasoning), working memory (mentally holding and manipulating information in real time), fluid reasoning (determining how visual objects are inherently related and thinking through the application of intricate rules), and processing speed (rate of visual recognition and efficiency in decision making). Together, these types of factors combine to form one’s overall IQ.

Although knowing one’s overall IQ is valuable, it can also be helpful for individuals to understand their cognitive strengths and weaknesses. For instance, one person with an average IQ may be quite strong in verbal comprehension but have a below average processing speed. Another person with the same overall IQ might have above average working memory, yet struggle with integrating and applying complex visual information. Although these two students have equivalent IQs, they may have significantly different approaches to learning.

Some intelligence tests emphasize attention as a part of IQ, whereas many theorists and psychological scientists consider attention to be an executive function that is moderately positively related to intelligence but not part of the same psychological construct. The current use of the term intelligence quotient is an artifact of the past, in which IQ was determined by dividing individuals’ mental age by their chronological age. Although the norms from which IQ scores are derived take age into account, the IQ score is now derived in a much more complex statistical fashion than applying a relatively simple quotient. It is important to point out that IQ tests individually administered by psychologists have greater reliability and validity than group-administered IQ tests, which often involve multiple students taking an IQ test at once with relatively little interaction with the examiner.

Applications for IQ

The role of IQ testing in the schools has changed somewhat because the emphasis on determining a learning disability used to be the IQ-achievement discrepancy. More recently, the psychological and clinical assessment of learning disabilities has placed a greater emphasis on the cognitive processes that contribute to strengths and weaknesses in achievement as well as how students respond to science-based interventions. In response, a greater emphasis is often placed on index scores and specific cognitive strengths and weaknesses (e.g., processing speed vs. working memory) rather than overall IQ. Furthermore, intelligence tests have been developed that focus on how students solve problems, such as the Wechsler Intelligence Scale for Children–Fifth Edition, Integrated, published in 2015. This test can help school and educational psychologists gain a deep understanding of how students approach academic and intellectual problems as well the conditions in which students perform better. In numerous studies, the strongest predictor of achievement is IQ; thus, schools that are attempting to elevate reading, science, and math achievement would be wise to include IQ within their models of achievement.

...