Theories of Intelligence

1
Theories of Intelligence
2
What is intelligence?

• APA Task Force
• Individuals differ from one another in their
  ability to understand complex ideas, to adapt
  effectively to the environment, to learn from
  experience, to engage in various forms of
  reasoning, to overcome obstacles by taking
  thought. Although these individual differences
  can be substantial, they are never entirely
  consistent a given persons intellectual
  performance will vary on different occasions, in
  different domains, as judged by different
  criteria. Concepts of intelligence are attempts
  to clarify and organize this complex set of
  phenomena.

3
Research Traditions

• Psychometric
• Examines elemental structure of a test
• Utilizes a factor analytic approach
• Information Processing
• Processes underlying learning and problem solving
• Cognitive
• How humans adapt to life demands

4
Binet Scales
5
What is factor analysis?

• Factor analysis is a tool to extract from a test
  what psychological dimensions are being measured.
• Goal Extract the fewest dimensions possible
• Method Correlation coefficient patterns are
  analyzed
• Assumption Co-occurrences tend to have a common
  cause

6
Early Binet Scales

• According to Binet (1905), intelligence is the
  capacity to
• Find and maintain direction or purpose
• Make strategic adjustments to achieve that
  purpose
• Engage in self criticism so that necessary
  adjustments in strategy can be made

7
Early Binet Scales

• Alfred Binets Principles of Intelligence Test
  Construction
• Principle 1
• Age differentiation
• Searched for tasks in which performance increased
  with age
• Allows for distinguishing chronological age from
  mental age

8
Early Binet Scales

• Alfred Binets Principles of Intelligence Test
  Construction
• Principle 2
• General Mental Ability
• Measured only the general product of the various
  and distinct elements of intelligence
• Selected tasks that correlated highly with each
  other

9
Sidebar Spearmans Model

• Charles Spearmans Model of General Mental
  Ability (1904, 1927)
• Defined intelligence as the ability to educe
  relationships or correlates
• Independent of Binet, proposed that intelligence
  is one general underlying factor (g) and a large
  number of specific factors (Two-Factor Theory)

10
Early Binet Scales

• 1905 Binet-Simon Scale
• 30 items presented in increasing order of
  difficulty
• Item 4 Recognizing difference between wood and
  chocolate
• Item 9 Name objects in a picture
• Item 14 Define familiar objects such as a fork
• Item 30 Define and distinguish abstract items
  (e.g., happy versus bored)
• Intellectual deficiency terms
• Idiot
• Imbecile
• Moron
• Norms based on 50 children

11
Early Binet Scales

• Age level 3
• Point to various parts of face
• Repeat two digits forward
• Age level 5
• Copy a square
• Repeat 10 syllable sentence
• Age level 10
• Given three common words, construct a sentence
• Recite the months of the year in order
• Age level 12
• Repeat 7 digits forward
• Provide the meaning of pictures

• 1908 Binet and Simon scale retained principle of
  age differentiation and introduced two major
  concepts
• Age scale format
• Mental age
• If a 10 year old can do no more than pass 2/3 to
  ¾ of the items that 5 year olds can pass, then
  the child has a mental age of 5

12
Stanford-Binet Intelligence Scale (L.H. Terman)

• 1917, 1937 Scales
• Increased size of standardization sample
• First application of the concept intelligence
  quotient (Stern, 1914)
• 16 years was the maximum mental age
• Difficulties
• Reliability of test varied with age and
  intelligence
• SDs differed across age

• Child 1
• Chronological Age (CA) 6 years
• Mental Age (MA) 6 years
• IQMA/CA 100
• IQ6/6100100
• Child 2
• CA 6 years MA 3 years IQ50
• Adult 1
• CA 50 years MA 16 years
• IQMA/CA 100
• IQ16/16100100

13
Stanford-Binet Intelligence Scale (L.H. Terman)

• 1960 Stanford-Binet Revision
• Deviation IQ
• Standard score with a mean of 100 and an SD16

14
Modern Binet Scale

• Fourth and Fifth Editions of Binet Scale based on
  hierarchical model of intelligence
• g
• gf-gc Theory of Intelligence (Cattell Horn,
  1978)
• Crystallized Intelligence (gc)
• Actual learning that has occurred
• Realization of potential through experience
• Fluid Intelligence (gf)
• Potential to learn
• Basic capabilities that one uses to acquire gc
• Short-term memory

15
Modern Binet Scale
General Intelligence
Fluid Reasoning
Nonverbal
Verbal
Knowledge
Nonverbal
Verbal
Quantitative Reasoning
Nonverbal
Verbal
Visual/Spatial Reasoning
Nonverbal
Verbal
Working Memory
Nonverbal
Verbal
16
Characteristics of Binet 2003, 5th Edition

• Book 1
• 2 routing tests that direct the examinee to a
  level of difficulty that is optimal
• Estimated level of ability is the start point
• Book 2
• 4 nonverbal age based subtests (knowledge,
  quantitative reasoning, visual-spatial
  processing, and working memory)
• Book 3
• 4 verbal age based subtests (fluid reasoning,
  quantitative reasoning, visual-spatial
  processing, and working memory)

17
Characteristics of Binet 2003, 5th Edition

• Scaled Scores (Mean100, SD15)
• Nonverbal IQ, Verbal IQ, Full-Scale IQ
• Fluid reasoning, knowledge, quantitative
  reasoning, visual-spatial processing, working
  memory
• Nominal categories designated according to cutoff
  boundaries
• Examples
• 145-160 Very Gifted
• 90-109 Average
• 40-54 Moderately impaired

18
The Wechsler Tests
19
Wechsler Tests

• David Wechsler
• Intelligence is the aggregate or global capacity
  of the individual to act purposefully, to think
  rationally, and to deal effectively with the
  environment
• Nonintellective factors must be taken into
  account, including personality traits (e.g.,
  drive, persistence, and goal awareness, potential
  to perceive and respond to social, moral, and
  aesthetic values)

20
Wechsler Tests

• Wechslers motivation
• Early Binet mental norms did not apply to adults
• Early Binet single score
• Early Binet emphasis on speed unduly handicapped
  older adults

21
Wechsler Tests

• Point Scale
• Points assigned for each passed item
• Makes it easy to group content-related items
• Performance Scale
• Measured nonverbal intelligence
• Required subjects to do something
• Performance and verbal scales standardized using
  the same sample

22
WAIS-III
23
Wechsler Tests

• Scores
• Verbal, Performance, Full-Scale IQ (mean100,
  SD15)
• Index scores verbal comprehension (crystallized
  intelligence), perceptual organization (fluid
  intelligence), working memory, processing speed
  (mean10, SD3)

24
Wechsler Tests

• Hypothetical Case Study Drop in grades

25
Wechsler Tests

• Hypothetical Case Study A slow learner

26
Measuring Intelligence Other Issues
27
(No Transcript)
28
Linking genes, brain structure and intelligence

• Francis Galton
• First to publish on the hereditability of
  intelligence
• Thought that the most intelligent were equipped
  with the best sensory capacities
• The only information that reaches us concerning
  outward events appears to pass through the
  avenues of our senses and the more perceptive
  the senses are of difference, the larger is the
  field upon which our judgment and intelligence
  can act.

29
Linking genes, brain structure and intelligence
30
Linking genes, brain structure and intelligence

• Brain Volume 85 heritable
• Brain Volume and Grey matter r.33
• Grey Matter and g r.25

31
Linking genes, brain structure and intelligence
32
Linking genes, brain structure and intelligence
33
Linking genes, brain structure and intelligence

• Fluid intelligence scores are impaired more by
  damage to frontal than posterior brain structures.

Negative scores indicate lower fluid intelligence
scores relative to control group.
34
Controversial Issues

• Should IQ tests be used to determine who
• gets into college?
• serves on a jury?
• gets special education classes?
• gets to be sterilized?

35
Controversial Issues

• We can imagine no recommendation for using the
  government to manipulate fertility that does not
  have dangers. But this highlights the problem
  The United States already has policies that
  inadvertently social-engineer who has babies, and
  it is encouraging the wrong women. (p. 548)

36
Controversial Issues

• We pass through this world but once. Few
  tragedies can be more extensive than the stunting
  of life, few injustices deeper than the denial of
  an opportunity to strive, or even to hope, by a
  limit imposed from without, but falsely
  identified as lying within.

37
Gene-environment interactions
38
Environmental Effects

• Franz Boass classic study, Changes in bodily
  form of descendants of immigrants
• Flynn Effect
• Stereotype threat (Claude Steele)
• Expectancy effects
• Effects of reinforcing responses