INTELLIGENCE AND PSYCHOLOGICAL TESTING What exactly is intelligence? How can it be measured? Where did it come from?

PSYCHOLOGICAL TESTS Psychological tests are standardized measurements of a sample of a person’s behavior whose results may or may not be representative → they can be divided into the two broad categories of mental ability and personality tests

PSYCHOLOGICAL TESTS Mental ability tests include intelligence, aptitude, and achievement tests → intelligence tests measure general mental ability and intellectual potential (as opposed to knowledge) → aptitude tests measure more specific mental ability (college entrance exams have been called ‘thinly disguised intelligence tests’) → achievement tests are designed to measure what a person has learned (AP tests, unit tests, etc.)

STANDARDIZATION AND NORMS Psychological tests are standardized: uniform testing procedures are used in administering and scoring the test → scores on these tests tell you how you score relative to other people based on the test norms (average?, above average?, below average?)

STANDARDIZATION AND NORMS Test norms can convert your ‘raw’ score into a percentile score, which indicates the % of people who score at or below your own score → Remember that in a normal distribution (bell curve) of IQ scores, your raw score of 115 puts you at the 84th percentile

RELIABILITY Test reliability refers to the extent that a test yields consistent results, which are necessary for accuracy → a test’s reliability can be measured by having subjects take a test twice (test-retest reliability); the closer the two test’s scores are to each other, the closer their correlation coefficient will be to +1, and the more reliable the test is

VALIDITY A test must also have validity: is it actually measuring what it is designed to measure? → content validity is necessary for achievement tests, such as unit exams – are the questions representative of the material learned in the unit?

VALIDITY → criterion-related validity is necessary to verify a test’s ability to make predictions about an individual’s behavior – it is achieved by having a strong positive correlation between the test and an independent assessment of the same trait measured by the test

VALIDITY → construct validity refers to how well a test measures abstract qualities - such as creativity, intelligence, or independence – called hypothetical constructs

THE EVOLUTION OF INTELLIGENCE TESTING 19th century British scholar Sir Francis Galton was a pioneer in the measurement of mental ability → Galton, who gave us the nature vs. nurture phrase, attempted to show intelligence was hereditary by measuring and correlating it to sensory processes

THE EVOLUTION OF INTELLIGENCE TESTING The French government hired Alfred Binet to develop an unbiased test to identify special needs to children in 1904 → Binet (along with Theodore Simon) developed a test to measure a child’s ‘mental age’, which indicated the child showed the mental performance of a child of a specific chronological age

THE EVOLUTION OF INTELLIGENCE TESTING Stanford University prof Lewis Terman adapted Binet’s test in 1916 and created the Stanford-Binet Intelligence Scale to measure natural intelligence → the Stanford-Binet measured scores as an IQ (Intelligent Quotient), originally determined as a child’s mental age ÷ its chronological age x 100

THE EVOLUTION OF INTELLIGENCE TESTING → Terman promoted the Stanford-Binet and it soon became – and remains today with revisions – a common measure of intelligence

THE EVOLUTION OF INTELLIGENCE TESTING The original IQ was fine for kids, but not adults; thus David Wechsler created an intelligence test for adults known as the Wechsler Adult Intelligence Scale (WAIS) → the most widely used adult test today, the WAIS changed the content of the S-B to include more nonverbal reasoning (it includes 15 subtests today)

THE EVOLUTION OF INTELLIGENCE TESTING → Wechsler also discarded the IQ (although we still use the term today) in exchange for a scoring system based on a normal distribution

THE STRUCTURE OF INTELLIGENCE British psychologist Charles Spearman believed we have one general intelligence (g) and special abilities identified by the statistical procedure he called factor analysis → despite these specific skills, Spearman said our g was the basis for all intelligent behavior

THE STRUCTURE OF INTELLIGENCE L.L. Thurstone strongly disagreed with Spearman (along with others, then and now) and his idea that we have one general intelligence → he proposed that we have 7 clusters of primary mental abilities

THE STRUCTURE OF INTELLIGENCE Despite Spearman’s idea of g still holding sway, today’s intelligence tests, clinicians, and educators focus on Thurstone’s more specific mental abilities → a basic breakdown of g into two components includes the ideas of fluid and crystal intelligence

THE STRUCTURE OF INTELLIGENCE 1. Fluid intelligence is our ability to reason and process information quickly and abstractly, especially in unique situations 2. Crystallized intelligence is our accumulated knowledge and verbal skills and the ability to use it all