What role do IQ tests play in measuring Intelligence?

IQ Test

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Human Intelligence ‘A Virtual Roundtable’ - Week 3

Three Cambridge University Press authors and leading experts on Intelligence take on our virtual roundtable on 'Human Intelligence'. Week three of the six part series asks the question 'What role do IQ tests play in measuring intelligence?'



James R. Flynn, University of Otago, New Zealand

Richard Haier, University of California, Irvine

Robert Sternberg, Cornell University, New York

What role do IQ tests play in measuring intelligence?

Richard Haier:

There is a broad recognition among psychologists that intelligence testing is one of the great accomplishments in the field. This is not to say there are not problems. There is a history of misuse and a history of misunderstanding what an IQ test measures. It is critically important to understand that all intelligence tests estimate but do not measure intelligence in the same way that a yardstick measures distance or a scale measures weight. Intelligence is not like distance or weight and IQ points are not the same kind of measurement as an inch or a pound. Ten pounds is literally twice as heavy as five pounds but someone with an IQ of 140 is not literally twice as smart as someone with an IQ of 70. IQ points have meaning only relative to other people (norms). This is a fundamental problem even though intelligence test scores predict many things quite well. I believe we are moving closer to having a measurement of intelligence that is more like measures of distance or weight. I’m talking about quantifiable measures of brain variables like processing speed or glucose metabolic rate or gray matter volume that might be translated into measures of intelligence. This is the next step beyond the limits of psychometric approaches (paper and pencil tests that compare an individual’s score to a normative group). A new generation of intelligence researchers is moving toward this goal and if combined with neuroscience approaches, there is every reason to expect great advancements in our understanding of intelligence and why some people are smarter than others.

James R.Flynn:

We want tests suited to our own society.  Wechsler tests help predict school and some job performance and Sternberg’s tests cover practical and creative tasks.  Look at the classical subtests:  block design, object assembly, and pictorial tests – measure on-the-spot problem solving; similarities – classifying based on abstractions; vocabulary, information, comprehension, and arithmetical reasoning – our capacity to deal with our social world; coding – speed of information processing; digit span backward – working memory

Within Western culture, higher IQ scores over time chart a fascinating progression from the people in 1900 to ourselves – James R.Flynn

Today’s adults today really do have larger vocabularies and can read more widely and converse more “intelligently”.  We really can better perform the tasks modern schooling and jobs (the professions, computer programming) demand.  A whole new world forces us to use logic on symbols far removed from the concrete world.  Pre-modern people see fish as having nothing in common with crows.  You can eat one and not the other; one swims, the other flies.  We divide creatures into categories that are non-observable but offer understanding: whales are more akin to land animals than fish; the tiny hyrax is more akin to the huge elephant than to the rodents it resembles.  Our whole picture of the universe (and even our approach to explaining human behaviour) is based on logic and abstractions. No one has ever observed the “x” of algebra.

Are we more “intelligent” than our ancestors?  I say:  we can attack a wider range of cognitive problems, but they were equally capable of solving the problems of their time; our brains would look different at autopsy because we have exercised them differently, but look no different at conception.  That is all you need to know and adding the label “more or less intelligent” adds nothing.

Robert Sternberg:

IQ tests are somewhat useful for measuring the analytical aspect of intelligence.  I say “somewhat” useful because they will tell you different things depending on the kind of environment in which a person grows up.  Urban children generally have an advantage over rural ones; children who are tested in a second language are at a disadvantage, as are children whose parents are uneducated.  The problem is not with the IQ tests, per se, but rather with society’s tendency to overinterpret and often misinterpret the results.

Consider some examples.

First, they have been used to predict achievement, whether grades in school or scores on achievement tests.  But the best predictor of future grades in school is past grades in school and the best predictor of future achievement test scores is past achievement test scores.  We don’t need IQ tests to predict achievement.  One might argue that the idea is to predict achievement from ability rather than from achievement, but IQ tests are achievement tests, albeit disguised ones.  They measure the achievements one was supposed to have acquired earlier in one’s life.

Second, they have been used to assess learning disabilities. But you do not need IQ tests to assess learning disabilities.  Research has suggested that children who have a weakness in a particular area need remediation in that area, regardless of IQ.  If someone is a poor reader, the person needs remediation in reading, regardless of IQ.

Third they have been used to identify students for gifted programs.  But we don’t need IQ tests for that.  If we care about gifted achievement, we should identify students on the basis of what they have achieved, not on the basis of a supposed ability test.

Bottom line: We don’t much need traditional IQ tests.

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Week 1 – Can We Define Intelligence?

Week 2 – What role does neuroscience play in understanding intelligence and our capacity to learn?

Week 3 – What role do IQ tests play in measuring intelligence?

Week 4 –How are technological advances, access to instant information and media forces affecting human intelligence?

Week 5 – How can current research inform the development of new methods to assess intelligence?

Week 6 – What does the future hold in the research of intelligence? How much smarter will we be in 100 years’ time?

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About the Author: James R. Flynn

James R. Flynn is the author of Does Your Family Make You Smarter? He is professor emeritus at the University of Otago, New Zealand, and a recipient of the University's Gold Medal for Distinguished Career Research. He is renowned for the 'Flynn effect', the documentation of massive IQ gains from one generation to another....

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About the Author: Richard Haier

Richard J. Haier earned is Professor Emeritus at the University of California and author of The Neuroscience of Intelligence....

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About the Author: Robert J. Sternberg

Robert J. Sternberg is Professor of Human Development at Cornell University, New York. Formerly, he was IBM Professor of Psychology and Education at Yale University, Connecticut. He won the 1999 James McKeen Cattell Fellow Award and the 2017 William James Fellow Award from APS. He is editor of Perspectives on Psychological Science. His main fields ...

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