Intelligence
Overview
1. Definition of intelligence
2. How to measure intelligence (WAIS-3)?
3. Important concepts related to developing/constructing intelligence tests such as standardization, validity, reliability, g vs. s factors.
4. Clinical implications of IQ (LD and MR)
5. Various issues related to intelligence (nature vs. nurture?, group differences in intelligence such as gender, race, age)
What is intelligence?
-Am I intelligent? Why or why not?
-Degree, handsome, money, GPA, gender, race, age, creativity, religious, friends, sensitivity, athletic ability, musical talent, street smart, etc.
-Definition:
The ability to learn from experience, to solve problems, to reason clearly, and to use acquired knowledge to adapt to new situations.
How to measure intelligence?
Wechsler Adult Intelligence Scale (WAIS-3):
-Most widely used intelligence test
-It consists of 11 subtests.
*VIQ: Verbal Reasoning.
- General Information: How far is it from D.C. to Seattle? How many days in a year?
- Vocabulary: Tell me the meaning of school. What does Erudite mean?
- Comprehension: What would you do if you found an envelope addressed and stamped in the street?
- Similarities: In what way are Salt and Water alike?
- Arithmetic reasoning: 5 X 6 / 2? You have 3 pennies and lost one, hoe many pennies left?
- Digit span: Repeat after me (forward and backward). 1962327
*PIQ: Performance
- Picture completion: Show a picture with an important part missing. What is missing?
- Picture arrangement: Put the pictures in the right order to tell the story.
- Block design: Make one just like using the 4 blocks.
- Object assembly: Showing many pieces and asking to put them together to make something.
- Digit-Symbol Substitution: asking to fill in the blanks based on the given pairs of number and symbols.
Principles of Test Construction
Standardization:
- Raw scores do not make any sense!
-Making raw scores meaningful relative to a pre-tested group.
-Comparing your performance with people with your age.
-German psychologist, Stern, devised “Intelligence Quotient (IQ).”
IQ = (Mental age / Chronological age) X 100.
Problems in this formula
Works well for children but not for adults (20 vs. 40)
Instead,
Mental age = One’s performance.
Chronological age = A level of performance that is typically expected or performed in a certain age. Statistically calculate (normal curve, 68/96%, mean=100, std=15)
Validity
-The extent to which a test is measuring what it was intended or supposed to measure?
Concurrent Validity (IQ vs. GPA)
Predictive Validity (IQ vs. Future performance)
(EX)Rubber band for head size?
G vs. S factor.
-Spearman ( “g” factor”): General intelligence inclusive of most factors.
(EX) WAIS?
(EX) “Savant Syndrome”? : limited ability in many areas but an exceptional skill in a certain area.
-Thurston and Gardner (“s” factors): Specific intelligence: VIQ, PIQ, FSIQ
Sternberg (85)
(1) Creativity? (Creative intelligence: Ability to adapt to new situations/generate novel ideas)
(2) Analytical, logical? (Analytical (academic) intelligence: Assessed by IQ test. Has a single answer)
(3) Street smart? (Practical Intelligence: Ability required for everyday tasks)
Cantor & Kihlstrom (87)
(1) Social intelligence: the ability to understand social situations and manage oneself successfully.
Salovey & Mayer (90):
(1) Emotional sensitivity? (The ability to perceive, understand, express, and regulate emotions)
Reliability
-The extent to which a test is producing a consistent score.
Test-retest (spring vs. winter)
Split /half (VIQ vs. PIQ)
Alternative form (WAIS2 vs. WAIS-3)
Clinical Implication of IQ test
-Classification: Mental Retardation: Mild (70-50), Moderate (49-35), Severe (34-20), Profound (19-0)
-Learning Disorder:
(a) 2 SDs diff:VIQ (Crystalized), PIQ (Fluid): 2 STDs
I(b) Diff between FSIQ and Reading, Writing, and Math.
Aptitude: Ability to learn a new skill
Achievement: Reflect what you have learned)
Various issues related to intelligence
- Nature vs. nurture
- Group differences in intelligence (gender, age, race)