Chapter 8: Testing and Individual Differences

Standardization and Norms

• When we say that a test is standardized, we mean that the test items have been piloted on a similar population of people as those who are meant to take the test and that achievement norms have been established.
• Such a group of people is known as the standardization sample.
• The psychometricians (people who make tests) at ETS use the performance of the standardization sample on the experimental sections to choose items for future tests.

Reliability and Validity

• Reliability refers to the repeatability or consistency of the test as a means of measurement.
  • The reliability of a test can be measured in several different ways.
• Split-half reliability involves randomly dividing a test into two different sections and then correlating people’s performances on the two halves.
• The correlation between performance on the different forms of the test is known as equivalent-form reliability.
• Test-retest reliability refers to the correlation between a person’s score on one administration of the test with the same person’s score on a subsequent administration of the test.
• A test is valid when it measures what it is supposed to measure.
• Validity is often referred to as the accuracy of a test.
• Face validity refers to a superficial measure of accuracy.
• Face validity is a type of content validity.
• Content validity refers to how well a measure reflects the entire range of material it is supposed to be testing.
• Concurrent validity measures how much of a characteristic a person has now; is a person a good chef now?
• Predictive validity is a measure of future performance; does a person have the qualities that would enable him or her to become a good chef?
• Construct validity is thought to be the most meaningful kind of validity.

Types of Tests

• Aptitude tests measure ability or potential, while achievement tests measure what one has learned or accomplished.
• Speed tests generally consist of a large number of questions asked in a short amount of time.
  • The goal of a speed test is to see how quickly a person can solve problems.
• Power tests consist of items of increasing difficulty levels.
• Some tests are group tests while others are individual tests.
• Group tests are administered to a large number of people at a time.

Theories of Intelligence

• Intelligence is a commonly used term, it is an extremely difficult concept to define.
  • Typically, intelligence is defined as the ability to gather and use information in productive ways.
• Fluid intelligence refers to our ability to solve abstract problems and pick up new information and skills, while crystallized intelligence involves using knowledge accumulated over time.

Charles Spearman

• Charles Spearman argued that intelligence could be expressed by a single factor.
• He used factor analysis, a statistical technique that measures the correlations between different items, to conclude that underlying the many different specific abilities s that people regard as types of intelligence is a single factor that he named g for general.

Howard Gardner

• Howard Gardner also subscribes to the idea of multiple intelligences.
• Unlike many other researchers, however, the kinds of intelligences that this contemporary researcher has named thus far encompass a large range of human behavior.

Daniel Goleman

• Recently there has been a lot of discussion of EQ, which is also known as emotional intelligence.
• One of the main proponents of EQ is Daniel Goleman.
• EQ roughly corresponds to Gardner’s notions of interpersonal and intrapersonal intelligence.

Robert Sternberg

• Robert Sternberg is another contemporary researcher who has offered a somewhat nontraditional definition of intelligence.
• Sternberg’s triarchic theory holds that three types of intelligence exist.

Intelligence Tests

• Alfred Binet was a Frenchman who wanted to design a test that would identify which children needed special attention in schools.
• Binet came up with the concept of mental age, an idea that presupposes that intelligence increases as one gets older.
• Louis Terman, a Stanford professor, used this system to create the measure we know as IQ and the test known as the Stanford-Binet IQ test.
• IQ stands for intelligence quotient.
• David Wechsler used a different way to measure intelligence.
• The Wechsler Adult Intelligence Scale (WAIS) is used in testing adults, the Wechsler Intelligence Scale for Children (WISC) is given to children between the ages of 6 and 16, and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) can be administered to children as young as 4.
• The Wechsler tests yield IQ scores based on what is known as deviation IQ.

Bias in Testing

• Much discussion has centered on whether widely used IQ tests and the SAT are biased against certain groups.
• Researchers seem to agree that although different races and genders may score differently on these tests, the tests have the same predictive validity for all groups.
• SAT scores are equally good predictors of college grades for different genders and for different racial groups and thus, in a sense, the test is clearly not biased.

Nature Versus Nurture: Intelligence

• An important term that researchers use in discussing the effects of nature and nurture is heritability.
• Heritability is a measure of how much of a trait’s variation is explained by genetic factors.
• Performance on intelligence tests has been increasing steadily throughout the century, a finding known as the Flynn effect.
• Research on identical twins separated at birth has found strong correlations in intelligence scores.
• Psychologists agree that racial differences in IQ scores are explained by differences in environment.

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