IQ (intelligence quotient) tests are a widely used method of gauging people's general intellectual abilities. Psychologists often use IQ tests to identify gifted students and to diagnose learning disabilities, under the assumption that IQ test scores accurately reflect intellectual ability. However, certain limitations of the test mean that you should interpret IQ test scores with a degree of caution.
IQ Tests and Test-Taking Abilities
IQ tests inadvertently measure test-taking abilities along with intellectual abilities. People who have a lot of experience with tests have an advantage on IQ tests compared with people who have not taken many tests. For example, the Wechsler Intelligence Scale for Children contains multiple-choice questions. If a child who regularly answers such questions at school scores higher than a child with no previous experience with multiple choice, it is not entirely clear whether the first child has higher intellectual abilities or is simply a better test-taker.
IQ Tests and Motivation
Another limitation of IQ tests is that highly motivated test takers score higher than people with less motivation. Considering the many ways in which psychologists use IQ tests, it can be hard to know how much a person's IQ score reflects their intellectual abilities or their motivation to do well on the test. According to psychologist Ulric Neisser, in the article "Rising Scores on Intelligence Tests," if the IQs of people in 1932 were tested by 1997's standards, their average IQ score would be 20 points below the average IQ in 1997. Doctor Neisser suggested that increased motivation to score highly on tests may have contributed to the increase in IQ scores over time.
IQ Tests Do Not Measure Every Kind of Intelligence
Another limitation of IQ tests is that they attempt to represent a person's overall intellectual abilities with a single score. According to psychologist Howard Gardner in his book "Frames of Mind: The Theory of Multiple Intelligences," people can use as many as seven distinct forms of intelligence, including musical, kinesthetic, and interpersonal intelligence. IQ tests may assess your logical thinking skills and memory, but fail to assess your interpersonal skills or creativity. So, someone who scores below average on an IQ test may still have exceptional creative abilities that IQ tests overlook.
An often-mentioned limitation of IQ tests is that they do not produce consistent scores across cultural groups. An IQ test may include questions that emphasize skills that are important to one cultural group, and neglect skills that are important to another cultural group. For example, according to Professor Judith Kearins, in the journal "Cognitive Psychology," Australian Aboriginal children who grew up in the desert scored above average on a test that measured visual memory, despite scoring below average on IQ tests. Professor Kearins suggested that visual memory is particularly important for the Aboriginal children as a means of way-finding in the desert.