Unit 11 – Intelligence and Personality

Assessing Intelligence and Test Construction

Alfred Binet• To minimize bias in French elementary schools, the government hired

Binet to study how to tell the differences among children related to their varying intelligences

• They found that “bright” children seemed to match intelligence with older children and “dull” children seemed to match intelligence with younger children• Intelligence concept – mental age: level of

performance typically associated with a certain chronological age• The average 9 year old has a mental age of 9

• Legacy – theorized mental aptitude is a general capacity that shows up in various ways

Lewis Terman – Stanford University

• The innate IQ – saw that Binet’s French test did not show equivalency in California school children• Intelligence Concepts• Stanford-Binet – widely used US version of

Binet’s intelligence test

• Legacy• Culture related to IQ tests in America

• Eugenics ()

William Stern

• Intelligence concept: IQ – intelligence quotient• IQ = (mental age/chronological age) X 100

• Legacy – although IQ tests are rarely used today, the term has stuck around. “IQ” tests today measure the test-taker’s performance relative to the average performance of others the same age

Modern Tests of Mental Abilities

• David Weschler created what is now the most widely used intelligence test• WAIS (Weschler Adult Intelligence Scale)• WISC (Weschler Intelligence Scale for Children)

WAIS

• Consists of 11 subtests broken into verbal and performance tests• Yields overall intelligence (like Stanford-Binet) but gives separate

scores for verbal comprehension, perceptual organization, working memory, and processing speed • Who does that sound like? Spearman or Thurstone?

WISC

• Same concept as WAIS but for kids• If we see striking differences between a child’s perceptual

organization and working memory compared to their verbal comprehension – there may be a disorder or disability present• WISC is often used to see if a child has a learning disability (like dyslexia)

Flynn Effect• Over time, intelligence test performance has been improving

Test Construction

• How do people incorrectly infer information from the following statement?• “I have an IQ 130!”

• We must have a basis for comparison in order for your score to be meaningful.• Standardization – defining meaningful scores relative to a pretested

group• Normal curve – typically, group members’ scores are distributed in a

bell-shaped pattern

Reliability: the extent to which a test yields consistent results, as assessed by the consistency of scores on two halves of the test or on retesting

• Test-retest – give individuals the same test at different times to check how consistent the scores are• Split-half – split the test in half and see whether odd question scores

and even question scores agree

• The higher the correlation between test-retest or split-half, the more reliable the test• Stanford-Binet, WISC and WAIS all have reliabilities of +.9 (Why would it only

be a positive correlation?)

Validity: the extent to which a test accurately predicts or measures what it promises• Content – extent to which a test samples the behavior that is of

interest (road test for driver’s ed, course exams, AP test)

• Construct – degree to which a test measures what it claims to measure (empirical research – conclusions to your thesis statement, papers)

• Predictive – predict the criterion of future performance (intelligence tests)