1. Assessing Intelligence
Module 31
Assessing Intelligence
Worth Publishers

2. Assessing Intelligence
One-Minute Intelligence Test

3. Origins of Intelligence Testing
Alfred Binet – French Psychologist
developed intelligence test when schools needed a way to objectively identify students with special needs
believed that all children follow same path of development, some develop more rapidly

4. Origins of Intelligence Testing
Mental Age
a measure of intelligence test performance devised by Binet
chronological age that most typically corresponds to a given level of performance
child who does as well as the average 8-year-old is said to have a mental age of 8

5. Origins of Intelligence Testing
Stanford-Binet
the widely used American revision of Binet’s original intelligence test
revised by Terman at Stanford University
extended range to include adults
Developed test to evaluate immigrants and WWI army recruits – cultural bias

6. Origins of Intelligence Testing
Intelligence Quotient (IQ)
defined originally the ratio of mental age (ma) to chronological age (ca) multiplied by 100
IQ = (ma/ca x 100)
on contemporary tests, the average performance for a given age is assigned a score of 100

7. Origins of Intelligence Testing
If mental and chronological age are the same, IQ = 100.
Most current intellectual tests, no longer measure an IQ.
Original formula works for children, not for adults.
Today’s intellectual tests compare mental ability score based on test-taker’s performance relative to the average performance of others that are the same age.
2/3 of all people score between

8. Assessing Intelligence
Aptitude Test
a test designed to predict a person’s future performance (ex. SAT)
aptitude is the capacity to learn
Achievement Test
a test designed to assess what a person has learned (ex. course exam)

9. Assessing Intelligence
Wechsler Adult Intelligence Scale (WAIS)
most widely used intelligence test
Subtests – (11)
verbal
performance (nonverbal)

10. Assessing Intelligence: Sample Items from the WAIS
From Thorndike and Hagen, 1977
VERBAL
General Information
Similarities
Arithmetic Reasoning
Vocabulary
Comprehension
Digit Span
PERFORMANCE
Picture Completion
Picture Arrangement
Block Design
Object Assembly
Digit-Symbol Substitution

11. Assessing Intelligence: Sample Items from the WAIS
Subtest of the WAIS-R -
Measures abilities to see similarities
(Transparency/Analogies)

12. Assessing Intelligence
To be widely accepted, intelligence tests have to be –
Standardized
Reliable
Valid
(Stanford-Binet, Wechsler tests met all three.)

13. Assessing Intelligence
Basis for comparing your score to others’ performance –
Give test to a representative group of people.
When people take test their scores are compared to the sample in #1.

14. Assessing Intelligence
Standardization
defining meaningful scores by comparison with the performance of a pretested “standardization group”
Normal Curve
the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes
most scores fall near the average, and fewer and fewer scores lie near the extremes

15. The Normal Curve (Transparency)

16. Getting Smarter? Flynn Effect

17. Flynn Effect Greater test sophistication? Better nutrition?
More education?
More stimulation in the environment?
Less childhood disease?
Smaller families and more parental involvement?

18. Assessing Intelligence
Reliability
the extent to which a test yields consistent results
assessed by consistency of scores on:
two halves of the test – split test – odd/even
alternate forms of the test
retesting
Validity
the extent to which a test measures or predicts what it is supposed to

19. Assessing Intelligence
Standardized Test
Chitlings Test
Morris Shoe Size Test –
Are these tests – standardized, reliable, valid?

20. Assessing Intelligence
Content Validity
the extent to which a test samples the behavior that is of interest
driving test that samples driving tasks
Criterion
behavior (such as college grades) that a test (such as the SAT) is designed to predict
the measure used in defining whether the test has predictive validity

21. Assessing Intelligence
Predictive Validity
success with which a test predicts the behavior it is designed to predict
assessed by computing the correlation between test scores and the criterion behavior
also called criterion-related validity

22. Assessing Intelligence
Greater correlation
over broad range
of body weights 10 9 8 7 6 5 4 3 2 1
Little corre-
lation within
restricted
range
Football linemen’s
success
Body weight in pounds
As the range of data under consideration narrows, its predictive power diminishes

23. The Dynamics of Intelligence
Mental Retardation
a condition of limited mental ability
indicated by an intelligence score below 70
produces difficulty in adapting to the demands of life
varies from mild to profound
Down Syndrome
retardation and associated physical disorders caused by an extra chromosome in one’s genetic makeup

24. The Dynamics of Intelligence (Transparency)