Encyclopedia of Clinical Neuropsychology

2018 Edition
| Editors: Jeffrey S. Kreutzer, John DeLuca, Bruce Caplan

Intelligence Quotient

  • Donald H. SaklofskeEmail author
  • Mike R. Schoenberg
  • David Nordstokke
  • Robi L. Nelson
Reference work entry
DOI: https://doi.org/10.1007/978-3-319-57111-9_1075




The IQ (intelligence quotient) is a quantitative or statistical representation of an individual’s score on a standardized intelligence test. The IQ score has been widely utilized to compare an individual’s intellectual ability with the average score obtained by a sample of “similar” people, usually of the same age group. Thus, for example, it is possible to state that a person’s intelligence, as reflected in an IQ test score, is higher (or lower) than the average or typical scores of their peers. There are numerous intelligence tests and various definitions of intelligence, so while the IQ gleaned from a test is akin to a “score” on that test, the interpretation and meaning may vary from test to test (“ Intelligence”).

Historical Background

The Foundations for the IQ Score

In 1884, Galton measured large numbers of people in an attempt to develop a test of intelligence. He measured many characteristics of people, such as head size, reaction time, and...

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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Donald H. Saklofske
    • 1
    Email author
  • Mike R. Schoenberg
    • 2
  • David Nordstokke
    • 3
  • Robi L. Nelson
    • 4
    • 5
  1. 1.Department of PsychologyUniversity of Western OntarioLondonCanada
  2. 2.Department of Psychiatry and Behavioral SciencesUniversity of South Florida College of MedicineTampaUSA
  3. 3.Werklund School of EducationUniversity of CalgaryCalgaryCanada
  4. 4.Department of Psychiatry and Behavioral SciencesUniversity of South Florida College of MedicineTampaUSA
  5. 5.Department of PharmacologyVirginia Commonwealth UniversityRichmondUSA