1. Measurement of Intelligence
9.2

2. Why do scores keep rising on intelligence tests?
Educators, politicians, and the media frequently worry over declining academic standards and students who don’t care.
Psychologist James Flynn discovered that people actually seem to be getting smarter, not dumber.
He looked at various intelligence tests from many different cultures and found that results increased, regardless of nationality or the type of test.
Why? Flynn discovered that neither better schooling nor nutrition played a role. The best hypothesis is that as our society becomes more complex and more technological, our brains are faced with more challenges from an early age; this environment may help us make the most of our mental capabilities.
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3. Two Intelligence Tests
You’ve likely taken both achievement tests (tests that show what you’ve learned) and aptitude tests (tests that are intended to predict your ability to learn new skills). There are also tests that are designed to measure your intelligence. The two most widely used intelligence tests are the Stanford-Binet Intelligence Scale and the Wechsler scales.

4. Two Intelligence Tests, cont’d
The Stanford-Binet Scale
Original test first used in 1905
Gave a score called a mental age (MA), which shows the intellectual level at which a child is functioning
After 1916, known as the Stanford-Binet Intelligence Scale
Version used today gives an intelligence quotient (IQ), or a number that reflects the relationship between mental age and chronological age:
Mental Age (MA)
IQ= x 100
Chronological Age (CA)
IQ is an example of a transformed score—any score that has been changed from a raw score in a systematic way.

6. Two Intelligence Tests, cont’d
The Wechsler Scales
Revised Wechsler Adult Intelligence Scale (WAIS-R) has subtests, each measuring a different intellectual skill
Scales do not use mental age
Scales measure both verbal and nonverbal abilities
WAIS-R scores based on comparisons of a person’s answers with the answers of others in the same age group

8. Reliability and Validity
Intelligence tests must be reliable and valid.
Test Reliability
The reliability of a test refers to its consistency.
One common way to show reliability is called test-retest reliability, which is determined by comparing scores earned by the same person on the same test taken at different times.
Test Validity
A test has validity if it measures what it is supposed to measure.
Test scores are compared with outside standards or norms to determine test validity.
Some psychologists believe that it is difficult to make definitive statements about the validity of IQ tests.

9. Controversies and Problems
In the early 1900s, intelligence tests were used to limit the number of immigrants entering the United States and many states sterilized “mentally defective” people.
Another controversy focused on cultural bias that charges that some tests give an advantage to a particular group of people.
Problems
Education, economic background, and motivation can affect the results of intelligence tests.
Stereotype threat (when people know about a negative stereotype that applies to them—regardless of the truth of the stereotype—the expectation can be self-conforming) is another problem associated with intelligence tests.
Conversely, subjects who are reminded of positive stereotypes tend to perform better than expected.