The Wechsler Adult Intelligence Scale (WAIS) intelligence quotient An intelligence quotient, or IQ, is a score derived from one of several different standardized tests designed to assess intelligence. The term "IQ", from the German Intelligenz-Quotient, was devised by the German psychologist William Stern in 1912 as a proposed method of scoring children's intelligence tests such as those developed by (IQ) tests are the primary clinical instruments used to measure adult and adolescent intelligence.[1] The original WAIS (Form I) was published in February 1955 by David Wechsler David "Wex" Wechsler was a leading American psychologist. He developed well-known intelligence scales, such as the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children (WISC), as a revision of the Wechsler-Bellevue Intelligence Scale.[2] The fourth edition of the test (WAIS-IV) was released in 2008 by Pearson Pearson plc is a London-based education and media conglomerate. It is the largest book publisher in the UK, India, Australia and New Zealand, and the second largest in the US and Canada. Marjorie Scardino has been CEO since 1997. The headquarters for Pearson is at 80 Strand, the former Shell Mex House. It is listed on the London Stock Exchange and.
The Wechsler-Bellevue tests were innovative in the 1930s because they gathered tasks created for nonclinical purposes for administration as a "clinical test battery".[3] Because the Wechsler tests included non-verbal items (known as performance scales) as well as verbal items for all test-takers, and because the 1960 form of Lewis Terman Lewis Madison Terman was an American psychologist, noted as a pioneer in educational psychology in the early 20th century at Stanford University. He is best known as the inventor of the Stanford-Binet IQ test. He was a prominent eugenicist and was a member of the Human Betterment Foundation. He also served as president of the American's Stanford-Binet Intelligence Scales The development of the Stanford-Binet Intelligence Scales initiated the modern field of intelligence testing. The Stanford-Binet test started with the French psychologist Alfred Binet, whom the French government commissioned with developing a method of identifying intellectually deficient children for their placement in special education programs were less cautiously developed than previous versions, Form I of the WAIS surpassed the Stanford-Binet tests in popularity by the 1960s.[2]
Wechsler defined intelligence as "The global capacity of a person to act purposefully, to think rationally, and to deal effectively with his/her environment."[4]
Contents |
WAIS
| This section requires expansion with: WAIS vs. WAIS-R above. |
The WAIS was initially created as a revision of the Wechsler-Bellevue Bellevue Hospital Center, founded on March 31,1736 and most often referenced just as "Bellevue", is the oldest public hospital in the United States. It is best known outside New York City from many literary, film, and television mentions as "Bellevue," most always in reference to its psychiatric facilities. It is located in New Intelligence Scale, which was a battery of tests published by Wechsler in 1939. The WBIS was composed of subtests that could be found in various other intelligence tests of the time, such as Robert Yerkes Robert Mearns Yerkes was an American psychologist, ethologist, and primatologist best known for his work in intelligence testing and in the field of comparative psychology. Yerkes was a pioneer in the study both of human and primate intelligence and of the social behavior of gorillas and chimpanzees. Along with John D. Dodson, Yerkes developed the' army testing program and the Binet Alfred Binet , French psychologist and inventor of the first usable intelligence test, known at that time as Binet test basically today called IQ test. His principal goal was to identify students who needed special help in coping with the school curriculum. Along with his collaborator Théodore Simon, Binet published revisions of his intelligence-Simon Théodore Simon was a French psychologist and psychometrician. He co-created the Binet-Simon Intelligence Scale tests with Alfred Binet scale. It was first published in February 1955 by David Wechsler David "Wex" Wechsler was a leading American psychologist. He developed well-known intelligence scales, such as the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children (WISC)
WAIS-R
The WAIS-R was published in 1981 and consisted of six verbal and five performance subtests. The verbal tests were: Information, Comprehension, Arithmetic, Digit Span, Similarities, and Vocabulary. The Performance subtests were: Picture Arrangement, Picture Completion, Block Design, Object Assembly, and Digit Symbol. A verbal IQ, performance IQ and full scale IQ were obtained.[5]
This revised edition did not provide new validity data, but used the data from the original WAIS; however new norms were provided, carefully stratified.[5]
WAIS-III
The WAIS-III was published in 1997. It provided scores for Verbal IQ, Performance IQ, and Full Scale IQ, along with four secondary indices (Verbal Comprehension, Working Memory, Perceptual Organization, and Processing Speed).
Verbal IQ (VIQ)
Included seven tests and provided two subindexes; verbal comprehension and working memory.
The Verbal comprehension index included the following tests:
- Information
- Similarities
- Vocabulary
The Working memory index included:
- Arithmetic
- Digit Span
- Letter-Number Sequencing
The seventh test; comprehension; was not included in any index
Performance IQ (PIQ)
Included seven tests and it also provided two subindexes; perceptual organization and processing speed.
The Perceptual organization index included:
- Block Design Block design is a subtest on many intelligence tests that measures visuospatial and motor skills. The testee is required to take blocks that have all white sides, all red sides, and red and white sides and arrange them according to a pattern. They are timed on this task and compared to a normative sample
- Matrix Reasoning
- Picture Completion
The Processing speed index included:
Two tests; Picture Arrangement and Object Assembly were not included in the indexes
WAIS-IV
The current version of the test, the WAIS-IV, which was published in 2008, is composed of 10 core subtests and five supplemental subtests, with the 10 core subtests comprising the Full Scale IQ. With the new WAIS-IV, the verbal/performance subscales from previous versions were removed and replaced by the index scores. The General Ability Index (GAI) was included, which consists of the Similarities, Vocabulary and Information subtests from the Verbal Comprehension Index and the Block Design, Matrix Reasoning and Visual Puzzles subtests from the Perceptual Reasoning Index. The GAI is clinically useful because it can be used as a measure of cognitive abilities that are less vulnerable to impairment.
Indexes and scales
There are four index scores representing major components of intelligence:
- Verbal Comprehension Index (VCI)
- Perceptual Reasoning Index (PRI)
- Working Memory Index (WMI)
- Processing Speed Index (PSI)
Two broad scores are also generated, which can be used to summarize general intellectual abilities:
- Full Scale IQ (FSIQ), based on the total combined performance of the VCI, PRI, WMI, and PSI
- General Ability Index (GAI), based only on the six subtests that comprise the VCI and PRI
Subtests
The Verbal Comprehension Index includes four tests:
- Similarities: Abstract verbal reasoning (e.g., "In what way are an apple and a pear alike?")
- Vocabulary: The degree to which one has learned, been able to comprehend and verbally express vocabulary (e.g., "What is a guitar?")
- Information : Degree of general information acquired from culture Culture is a term that has various meanings. For example, in 1952, Alfred Kroeber and Clyde Kluckhohn compiled a list of 164 definitions of "culture" in Culture: A Critical Review of Concepts and Definitions. However, the word "culture" is most commonly used in three basic senses: (e.g., "Who is the president of Russia?")
- Comprehension [Supplemental]: Ability to deal with abstract social conventions, rules and expressions (e.g., "What does Kill 2 birds with 1 stone metaphorically mean?")
The Perceptual Reasoning Index comprises five tests
- Block Design Block design is a subtest on many intelligence tests that measures visuospatial and motor skills. The testee is required to take blocks that have all white sides, all red sides, and red and white sides and arrange them according to a pattern. They are timed on this task and compared to a normative sample: Spatial perception, visual abstract processing & problem solving
- Matrix Reasoning: Nonverbal abstract problem solving, inductive reasoning Inductive reasoning, also known as induction or inductive logic, is a type of reasoning that involves moving from a set of specific facts to a general conclusion. It uses premises from objects that have been examined to establish a conclusion about an object that has not been examined. It can also be seen as a form of theory-building, in which, spatial reasoning Academia has latched onto using this unfamiliar scientific term in describing research interests and publications on particular subject matter. Although Spatial-temporal can simply mean "relative to time and space" it is ironically not in the common-sense background knowledge of the general population . It is generally accepted that in
- Visual Puzzles: non-verbal reasoning
- Picture Completion [Supplemental]: Ability to quickly perceive visual details
- Figure Weights [Supplemental]: quantitative and analogical reasoning
The Working Memory Index is obtained from three tests
- Digit span: attention, concentration, mental control (e.g., Repeat the numbers 1-2-3 in reverse sequence)
- Arithmetic: Concentration while manipulating mental mathematical problems (e.g., "How many 45-cent stamps can you buy for a dollar?")
- Letter-Number Sequencing [Supplemental]: attention and working memory (e.g., Repeat the sequence Q-1-B-3-J-2, but place the numbers in numerical order and then the letters in alphabetical order)
The Processing Speed Index includes three tests
- Symbol Search: Visual perception, speed
- Coding: Visual-motor coordination Motor coordination is a term used to refer to the coordination of movements, usually between different subsequent parts of the same movement or movements of several limbs or even several actors. Motor coordination arise from a complex coordination between:, motor and mental speed
- Cancellation [Supplemental]: visual-perceptual speed
Standardization
The WAIS-IV was standardized on a sample of 2,200 people in the United States ranging in age from 16 to 90. An extension of the standardization has been conducted with 688 Canadians in the same age range. The median In probability theory and statistics, a median is described as the numeric value separating the higher half of a sample, a population, or a probability distribution, from the lower half. The median of a finite list of numbers can be found by arranging all the observations from lowest value to highest value and picking the middle one. If there is Full Scale IQ is centered at 100[6], with a standard deviation In probability theory and statistics, the standard deviation of a statistical population, a data set, or a probability distribution is the square root of its variance. Standard deviation is a widely used measure of the variability or dispersion, being algebraically more tractable though practically less robust than the expected deviation or of 15. In a normal distribution In probability theory and statistics, the normal distribution, or Gaussian distribution, is an absolutely continuous probability distribution whose cumulants of all orders above two are zero. The graph of the associated probability density function is “bell”-shaped, with peak at the mean, and is known as the Gaussian function or bell curve:[, the IQ range of one standard deviation above and below the mean (i.e, between 85 and 115) is where approximately 68% of all adults would fall.
Other test variants and uses
The WAIS-IV measure is appropriate throughout adulthood and for use with those individuals ages 16–90:11 years of age (this is an expanded age range for adults 74-90, reflecting the increased average life expectancy). For persons under 16, the Wechsler Intelligence Scale for Children (WISC The Wechsler Intelligence Scale for Children , developed by David Wechsler, is an intelligence test for children between the ages of 6 and 16 inclusive that can be completed without reading or writing. The WISC generates an IQ score, 6-16 yrs) and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI The Wechsler Preschool and Primary Scale of Intelligence is an intelligence test designed for children ages 2 years 6 months to 7 years 3 months developed by David Wechsler in 1967. It is a descendent of the earlier Wechsler Adult Intelligence Scale and the Wechsler Intelligence Scale for Children tests, 2 1/2-7yrs, 3mos) are used.
A short, four-subtest version of the WAIS-III battery has been released, allowing clinicians to form a validated estimate of verbal, performance and full scale IQ in a shorter amount of time. The Wechsler Abbreviated Scale of Intelligence (WASI) uses vocabulary, similarities, block design Block design is a subtest on many intelligence tests that measures visuospatial and motor skills. The testee is required to take blocks that have all white sides, all red sides, and red and white sides and arrange them according to a pattern. They are timed on this task and compared to a normative sample and matrix reasoning subtests similar to those of the WAIS to provide an estimate of full scale IQ in about 30 minutes.
Intelligence tests also are used in populations with psychiatric illness or brain injury, though some regard this use as controversial. Some neuropsychologists use the technique on people suffering brain damage as it leads to links Mixed receptive-expressive language disorder is a communication disorder in which both the receptive and expressive areas of communication may be affected in any degree, from mild to severe with which part of the brain has been affected, or use specific subtests in order to get an idea of the extent of the brain damage. For example, digit span may be used to get a sense of attentional difficulties. Others employ the WAIS-R NI (Wechsler Adult Intelligence Scale-Revised as a Neuropsychological Instrument), another measure published by Harcourt. Each subtest score is tallied and calculated with respect to non-normal or brain-damaged norms. As the WAIS is developed for the average, non-injured individual, separate norms were developed for appropriate comparison among similar functioning individuals.[citation needed]
References
- ^ Lichtenberger, Elizabeth O.; Kaufman, Alan S (2002). Assessing adolescent and adult intelligence. Boston: Allyn and Bacon. pp. 3. ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 020530527x.
- ^ a b Lichtenberger, Elizabeth O.; Kaufman, Alan S (2002). Assessing adolescent and adult intelligence. Boston: Allyn and Bacon. pp. 7. ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 020530527x.
- ^ Lichtenberger, Elizabeth O.; Kaufman, Alan S (2002). Assessing adolescent and adult intelligence. Boston: Allyn and Bacon. pp. 6. ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 020530527x.
- ^ Wechsler, David (1939). The measurement of adult intelligence. Baltimore: Williams & Wilkins. p. 229.
- ^ a b "Wechsler Adult Intelligence Scale--Revised". http://www.cps.nova.edu/~cpphelp/WAIS-R.html. Retrieved 2009-03-31.
- ^ "Distribution of IQ Scores". MSN Encarta. http://encarta.msn.com/media_461540296/Distribution_of_IQ_Scores.html. Retrieved 2007-07-08.
External links
- http://pearsonassessments.com/HAI/Images/site/Products/WAIS-IV/WAIS-IV_Intro/WAIS-IV_Intro.html
- Axelrod BN, & Ryan JJ. (2000). Prorating Wechsler Adult Intelligence Scale-III summary scores. Journal of Clinical Psychology. 56 (6), 807-11. PubMed
- Ryan JJ, & Schnakenberg-Ott SD. (2003). Scoring reliability on the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). Assessment. 10 (2), 151-9. PubMed
Categories: Intelligence tests Categories: Cognitive tests | Psychological testing | Intelligence | Cognitive tests Categories: Cognitive therapy | Psychological testing | Neuropsychological tests
|
Thu, 05 Aug 2010 11:59:38 GMT+00:00
Catholic Herald Online Prior has an IQ of 234, although it was once measured as 238 on the Wechsler Adult Intelligence Scale at university. This was so high that they asked him to ...
lanceluzy
Fri, 18 Dec 2009 18:17:51 GM
There are various tests done to know the intelligence of a person and then the IQ score is calculated. This was introduced by William Stern from Germany. The various tests conducted to assess the IQ are . Wechsler adult intelligence scale. ...
