Intelligence and Testing

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Intelligence and Testing
Chapter 8
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What is intelligence?

• intelligence A general term referring to the
  ability to learn and develop adaptive behaviors.
  
• intelligence tests Tests designed to measure a
  persons general mental abilities.

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Theories of Intelligence

• Charles Spearmans genreal intelligence g
• L. L. Thurstones Seven Mental Abilities
• Raymond B. Cattell's Two-Factor Theory
• Robert Sternbergs Triarchic Theory
• Howard Gardners Theory of Multiple Intelligences

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Charles Spearmans Theory

• g factor (general intelligence)
  Spearman stressed a general mental
  energy that can be channeled in various
  directions. Intelligent people can perform well
  in many areas.
• s factors (specific intelligence)
  reflect specific knowledge and
  abilities that are only used when performing
  specific tasks that have been leaarned.

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Thurstones Seven Primary Mental Abilities

• In contrast, L. L. Thurstone said primary mental
  abilities are independent of each other. A
  person could excel in one area and be very
  average in others.
• Thurstones seven primary mental abilities
• spatial visualizations
• verbal meaning word fluency
  
  
• number facility memory
• reasoning perceptual
  speed

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Sternbergs Triarchic Theory
We all share these three types of intelligence
but excel in ore or two areas
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Sternbergs Triarchic Theory

• componential Ability to acquire new knowledge
  and solve problems effectively (intelligence as
  we think of it).
  
• experiential The ability to adapt creatively in
  new situations (ability to meet new challenges).
  
• contextual Ability to select contexts in which
  you can excel (e.g., being able to make the right
  career choice).

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Gardners Theory of Multiple Intelligences
Much like Thurstone, Gardner suggests, seven
independent areas (types) of intelligence.

• logical-mathematical - Newton, Einstein
• linguistic - Whitman, Shakespeare
• spatial - Picasso, DaVinci, F. L. Wright
• musical - Mozart, Gershwin, Eric Clapton
• body-kinesthetic - M. Jackson, M. Jordan
• interpersonal - Ghandi,Carter, Nixon
• intrapersonal - to know oneself

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Gardners Theory

• logical-mathematical Ability to handle chains
  of reasoning, numerical relations, and
  hierarchical relations.
  
• linguistic Sensitivity to the meaning and order
  of words, as well as the functions of language.
  
• spatial Ability to perceive the world
  accurately and to transform and recreate
  perceptions.
  
• musical Sensitivity to pitch, tone, timbre, and
  musical patterns.

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Gardners Theory

• body-kinesthetic Ability to use ones body or
  to work with objects in highly differentiated and
  skillful ways.
  
• interpersonal Ability to notice and make
  distinctions among the moods, temperaments,
  motivations, and intentions of others.
  
• intrapersonal Ability to understand ones own
  feelings and use them to guide behavior.

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Daniel Goleman Emotional Intelligence

• Relatively new area of study
• understanding and managing ones own emotions is
  probably MORE vital to success than pure
  intellectual ability
  
• Many highly successful people are not brilliant
  and many geniuses die in poverty
  
• Understanding the emotions of others is also
  important. It allows us to predict how they will
  act in various situations

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Raymond Cattell Two Factor Theory(not in book)

• fluid intelligence General mental energy (like
  g). like a fluid, it shapes itself to the
  task (e.g., math, music, chemistry).
  
• crystallized intelligence Knowledge that is
  learned or accumulated over a lifetime.
  
• Crystallized intelligence is more stable across
  the lifespan whereas fluid intelligence begins a
  slow decline in middle adulthood.

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Cattells Other Contributions

• Personality A leader in personality theory and
  testing as well
  
• Cattell developed the 16 pf (personality factor)
  Inventory
  
• He applied the technique of factor analyses
  (deveoped by Spearman) to the study of
  intelligence and personality
  
• Factor Analysis statistical (mathematical)
  method for identifying the basic factors of
  intelligence and personality

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Intelligence Tests

• The Binet-Simon Scale
• The Stanford Binet
• The Weschler Scales
• WAIS (Weschler Adult Intelligence Scale)
• WISC (Weschler Intelligence Scale for Children)
• WPPSI (Weschler Preschool/Primary Scales of
  Intelligence)
  
• culture fair tests
• performance tests

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The Binet-Simon Scale

• Binet-Simon Scale The FIRST intelligence
  test. Alfred Binet was commissioned by the
  French Government to identify children with
  special learning needs
• Binet developed the concept of Mental Age
• mental age a child who scored the same as the
  average child of a given age on a standardized
  test had that mental age
  
• example if a 10 year old scored the same as the
  average 12 year old, he had a mental age of 12

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The Stanford-Binet

• Louis M. Terman working at Stanford University,
  developed an English version of the
  Binet-Simon
  
• Longitudinal Study Terman also began a long-term
  study of gifted children
  
• Intelligence Quotient (IQ) credited to Terman.
  Expesses the relationship between mental age
  and chronological age as a single number (a
  quotient)
• IQ mental age/chronological age 100

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Examples of IQ Computation

• a ten year old scores at the level of the
  average 12 year old on a given test
  
• 12/10 100 120 (a bright 10 year old)
• a ten year old scores at the level of the
  average 8 year old on a given test
  
• 8/10 100 80 (a below average 10 year old)

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The Stanford-Binet yields an overall IQ plus four
area IQs

• 1. verbal reasoning
• 2. abstract/visual reasoning
• 3. quantitative reasoning
• 4. short-term memory

The Stanford-Binet overall IQ and area IQs have a
mean of 100 and standard deviation of 15
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David Wechslers Contribution

• Wechsler noted that the Stanford-Binet was
  designed primarily for children
  
• Weshsler developed a test for adults (the WAIS)
  Wechsler Adult Intelligence Scale
  
• The WAIS yields an overall IQ plus two area
  IQs verbal and performance
  
• Like the Stanford-Binet, the WAIS overall IQ and
  area IQs have a mean of 100 and standard
  deviation of 15

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Wechsler Extends His Work

• Wechsler developed a test for (1) older children
  and adolescents (WISC) Wechsler Intelligence
  Scale for Children and (2) young children (WPPSI)
  Wechsler Preschool/Primary Scales of
  Intelligence
• Because each test covers a narrow age range and
  is easier to use, the Wechsler scales have
  surpassed the Stanford-Binet as the most widely
  used IQ tests

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Test Administration

• The Stanford-Binet, Wechsler Scales, and other IQ
  test are administered individually (one examiner
  to one test taker). One takes about 90 minutes.
  
• The testing process can be lengthy and tiring for
  examiner and test taker
  
• There are group (pencil and paper) IQ tests which
  are less accurate

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What does an IQ score mean?(See Appendix A in
book)

• To answer this we need to know a little bit about
  STATISTICS
  
• Statistics branch of mathematics used to
  organize and analyze data
  
• 3 important statistical concepts
• measures of central tendency
• measures of variability
• the normal or bell curve

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Three Measures of Central Tendency

• 1. Mode the most frequently occurring score
  (2,3,5,2,4,6) the mode is 2
  
• 2. Median score that divides the distribution of
  scores in half (2,4,5,8,9) the median is 5
  
• 3. Mean the arithmetic average (2356) / 4
  4

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Two Measures of Variability

• 1. Range difference between the highest and
  lowest scores in a distribution (2,5,3,9,7) the
  range is 9 -2 7
  
• 2. Standard Deviation a more useful measure the
  average distance that a group of scores are from
  their mean
  
• 7 scores (85, 90, 95, 100, 105, 110, 115) What
  is the average distance that these scores are
  from their mean (100)?

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Computing the standard deviation
85 - 100 -15 (-15)2 225
90 - 100 -10 (-10)2 100
95 - 100 - 5 (-5)2 25
100 -100 0 (0)2 0
105 -100 5 (5)2 25
110 -100 10 (10)2 100
115 -100 15 (15)2 225
? 700
700 / 7 100
100 10
The standard deviation is 10
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The Normal Distribution (Bell Curve)

• Is a hypothetical bell shaped curve that
  approximates the distribution of scores
  (characteristics) found among most naturally
  occurring variables
• some naturally occurring variables are height,
  weight, personality traits, and IQ!
  
• The normal distribution is marked off in
  standard deviations with 0 at the center
  
• IN the next slide, the percentages for each part
  of the curve are shown. Note, they add up to 100

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The Normal Distribution (Bell Curve)marked
off in standard deviations (SD)

• Intelligence is a naturally occurring
  variable. IQ is, therefore, normally
  distributed. recall, Mean 100, SD 15
  
• So, for all people in the U.S. (or any other)
  population
  
• 68 have IQs between and - 1 SD (85 - 115)
• 95 have IQs between and - 2 SD (70 - 130)

2.5 13.5 34
34 13.5
2.5
-2 -1 0
1 2
70 85 100
115 130
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a more complete distribution of IQ scores going
out to about and - 4 standard deviations
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Performance and Culture-Fair Tests

• performance tests Intelligence tests that
  minimize the use of language.
  
• culture-fair tests Intelligence tests that
  eliminate cultural bias by minimizing skills
  and values that vary from one culture to another
  (e.g., what to do if another child hits you?)
  Children of different Social Classes would
  answer differently.
• Progressive Matricesan example of a test that is
  both a performance test and a culture-fair test

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What Makes a Good Test Psychometrics

• 1. reliability Ability of a test to produce
  consistent and stable scores.
  
• 2. validity Extent to which the test measures
  what we think it measures.
  
• correlation Statistical measures of the
  strength and direction of the relationship
  between two variables. Correlation ranges from
  -1 to 1
• Both reliability and validity are established via
  correlations

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Reliability

• Five people take the same test twice on Monday
  and again on Friday
  
• person Monday Score Friday Score
• A 100
  80
  
• B 140
  90
  
• C 75
  120
  
• D 80
  130
  
• E 150
  90
  
• Correlation is low Reliability is poor
  

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Reliability

• Five people take the same test twice on Monday
  and again on Friday
  
• person Monday Score Friday Score
• A 100
  102
  
• B 140
  138
  
• C 75
  72
  
• D 80
  79
  
• E 150
  155
  
• Correlation is high Reliability is good

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Reliability

• carry over effects can occur when the first
  administration of a test influences the score on
  a second testing.
  
• split-half reliability A method of determining
  test reliability by dividing a test into two
  halves and correlating the two halves.
  Eliminates carry over effects.

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Establishing Validity of a New Test

• Five people complete our new IQ test and an
  established test (e.g., Stanford-Binet)
  
• person New Test Established
  Test
  
• A 70
  102
  
• B 140
  90
  
• C 75
  135
  
• D 80
  122
  
• E 150
  75
  
• Correlation is low Validity is poor

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Establishing Validity of a New Test

• Five people complete our new IQ test and an
  established test (e.g., Stanford-Binet)
  
• person New Test Established
  Test
  
• A 100
  102
  
• B 140
  138
  
• C 75
  72
  
• D 80
  79
  
• E 150
  155
  
• Correlation is high Validity is good

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Types of Validity

• content validity extent to which a test contains
  questions that cover all aspects of the subject
  being tested
  
• criterion validity the new test is compared to a
  criterion or standard to establish its
  validity
  
• face validity what the questions are measuring
  is very obvious (e.g., Are you depressed?).
  Sometimes a problem in personality, attitude, or
  clinical testing

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Positive Aspects of Individual Testing

• problems (lack of motivation) can be detected
• tests can be tailored for those with special
  needs
  
• tests are quite accurate and reliable

Criticisms of Individual Testing

• possibility of Halo Effect (a positive or
  negative bias on the part of the examiner)
  
• tests are time consuming and expensive
• tests can give an unfair advantage to those of
  higher SES in school placement situations
  
• tests may contain cultural-ethnic biases

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What Determines Intelligence?(Nature vs. Nurture)

• Heredity
• Tryons maze bright and maze dull rats
• IQ correlations in humans

• Environment
• Tryons and Rosenzweigs rat studies
• H. M. Skeels study of mentally retarded orphans

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Evidence for Heredity

• Robert Tryon taught rats to run a maze
• He bred the fastest learners with other fast
  learners over several generations
  
• He did the same with the slowest learners
• After several generations, he had two distinct
  populations maze bright rats who learned
  quickly and maze dull rats who learned slowly

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Evidence for HeredityIQ and Familial
Relationships
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Evidence for Environment

• Research by both Robert Tryon and Mark
  Rosenszweig showed that rats raised in a
  stimulating environment had more well developed
  brains and were brighter than rats raised in a
  plain and boring environment

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Evidence for Environment

• H. M. Skeels studied two groups of below average
  IQ orphans
  
• One group was placed in a setting where they had
  attention from adult patients (also below
  average IQ)
  
• The other group remained in the orphanage,
  receiving little attention
  
• IQ scores INCREASED for the group placed with
  the adults

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The Flynn Effect

• Professor James Flynn has noted that IQ scores
  worldwide have been increasing several points per
  decade since the 1930s
  
• However, nobody, as yet, is sure exactly why.
• Are we getting more intelligent, and if so why?
• Maybe just getting better at taking tests.

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Gender Differences in Intelligence

• Recent research finds little difference in the
  math and verbal abilities of males and females.
  
• Males do have better spatial ability than
  females.
  
• The average male and female IQ is about the same,
  but there is a higher proportion of men at the
  two extremes.

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Extremes of Intelligence

• mental retardation The condition of
  significantly subaverage intelligence (IQ below
  70) combined with deficiencies in adaptive
  behavior.
• giftedness Refers to superior IQ combined with
  demonstrated or potential ability in such areas
  as academic aptitude, creativity, and leadership.

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Levels of Mental Retardation
Mild - 50 through 70 may be able to function in
dependently Moderate 35 through 50 will nee
d some level of care and supervision
Severe 20 through 35 will need extensive car
e and supervision Profound 0 through 20 inca
pable of the even the simplest tasks
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Some Genetic Causes of Retardation

• Down syndrome results from an extra defective
  21st chromosome (also called Trisomy 21).
  
• phenylketonuria (PKU) An enzyme needed for
  metabolizing certain foods is absent. Toxins
  collect and damage the nervous system
  
• fragile-X syndrome due to a defect on the X
  chromosome

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Other Causes of Retardation

• alcohol or other drugs during pregnancy
• exposure to toxins or radiation during pregnancy
• maternal illness during pregnancy
• birth trauma
• malnutrition/deprivation during childhood
• numerous other causes

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Creativity

• The ability to produce novel and socially valued
  ideas or objects.
  
• Creativity differs from giftedness
• One can be very creative without having superior
  intelligence