Intelligence - the ability to comprehend; to understand & profit from experience.


* Spearman's two-factor theory of intelligence
     g - general mental ability factor.
     s - specific mental factors such as mathematical, mechanical, & verbal.

     Charles Spearman (1927) analyzed the relations among experimental intelligence tests using 
'factor analysis'. He argued that, as a rule, people who do well on some intelligence tests also 
do well on a variety of intellectual tasks [vocabulary and mathematical and spatial abilities]. And 
if people did poorly on an intelligence test, then they also tended to do poorly on other intellectual 
tests. That is, he observed correlations among performance on a variety of intellectual tasks.
     Thus, he proposed, a 'two-factor' theory of intelligence:
 1. General Ability (g): which was required for performance of mental tests of all kinds; he called this 
a kind of 'mental energy' that underlies the specific factors
 2. Special Abilities (s) which were required for performance on just one kind of mental test.
      - e.g. Scores on a verbal comprehension test are largely determined by one’s level of general 
intelligence but they are also affected by one’s specific ability to perform verbal comprehension tasks.


Ψ  Robert Sternberg (1949 - ) "I define [intelligence] as your skill in achieving whatever it is you want to attain in your
life within your sociocultural context by capitalizing on your strengths and compensating for, or correcting, your 
weaknesses ( personal communication, July 29, 2004)."

* Sternberg's triarchic theory (3 factors)
     1. analytical - logical - academic
          2. creative - problem-solving
               3. practical

Ψ  Sternberg (1986) believes that conventional intelligence tests tell us little about performance in everyday life 
& suggests a number of reasons why so-called intelligent people fail.

•  lack of motivation 
 •  lack of impulse control 
  •  lack of perseverance 
   •  fear of failure 
    •  procrastination 
     •  inability to delay gratification 
      •  too little or too much self-confidence    

Ψ  Sternberg suggests that if intelligence is properly defined & measured it must  translate into real-life success.


Ψ  Howard Gardner's original multiple-intelligence theory (1983) proposed 7 factors. 
     1. Linguistic 
      2. Logical-Mathematical 
       3. Musical 
        4. Spatial 
         5. Body-Kinesthetic 
          6. Interpersonal (social-understanding) 
           7. Intrapersonal (self-understanding) 
Ψ  In his book "Intelligence Reframed (1999)" Gardner proposed three more areas of intelligence: 
             8. Naturalistic ( knowledge of the living world ) 
              9. Spiritual ( an understanding of our relationship to the supernatural )
               10. Existential ( a concern with "ultimate" issues - a knowledge of our place in 
                      the cosmos )

Measuring Intelligence - Psychometrics

            Head size & grade point averages (intelligence) studied by Francis Galton.
            Brain size & intelligence studied by Paul Broca.

•  Neither head size, brain size or sex differences have a correlation with IQ or achievement.

    Binet's breakthrough in psychometrics produced the Binet-Simon Intelligence Scale which used Mental 
Age as a measure of intelligence.

    Terman's formula for ratio IQ: Intelligence Quotient equals Mental Age divided by Chronological 
Age times 100.

                                                 IQ = MA / CA x 100

Today the ratio IQ has been replaced by; deviation IQ which is statistically better.

Most widely used of IQ tests:
  Wechsler Adult Intelligence Scale (WAIS-III)
  Wechsler Intelligence Scale for Children (WISC-IV)

  All of the Wechsler scales are divided into six verbal & five performance subtests. 
  A trained examiner administers the test on a one to one basis.

Two characteristics of "good" tests; they have:
1. Validity - measure what they are supposed to.
    2. Reliability - they return the same results on retest.

Distribution & Use of IQ Scores

Mental retardation: IQ scores:
 Borderline mentally retarded: 50 - 75
    Mild/moderately mentally retarded: 35 - 50
      Severe/profoundly mentally retarded: 20 - 40

* Mental retardation causes:
    1. Organic retardation
        2. Cultural-familial retardation

Vast majority (95%) of IQ scores: 70 to 130

•  IQ scores & academic achievement - medium strength correlation
•  IQ scores & job performance - low to medium strength correlation

Gifted IQ scores: superior 130 - 145; gifted 145+

•  Binet's two warnings on potential problems of IQ Testing:
    1. Intelligence tests do not measure innate abilities or natural intelligence.
        2. Intelligence tests, by themselves, should not be used to label people. 

Match the following terms by drawing a line to their definitions.

Heritability                                    A bell-shaped frequency distribution curve. 
Intelligence Quotient                    The idea that love consists of: passion, intimacy, & commitment. 
Normal Distribution                       Represents a person's ability to perform complex mental work 
                                                     (abstract reasoning & problem solving). 
Validiy                                          A statistical measure that estimates the proportion of some trait that 
                                                     can be attributed to genetic factors. 
g                                                  Intelligences: verbal , musical, to understand oneself, to understand 
                                                    others, logical-mathematical, spatial, & body movement. 	
Sternberg's Triarchic Theory        The extent to which a test measures what it is supposed to measure.  	
Triangular Theory                        The extent to which IQ scores may increase or decrease as a result of 
                                                     interaction with environmental factors. 
Reliability                                    Computed by dividing a child's mental age, by the chronological age & 
                                                    multiplying the result by 100. 
Reaction Range                           The extent to which a test is consistent. 
Gardner's Theory                         Includes analytical, problem-solving, & practical reasoning processes.  

Study Questions

1. Would a new test based on a very accurate account of all the cells in your brain be a good test of intelligence?
2. If you were hiring for a large department store, would it help to know the applicant's IQ scores?
3. If parents wanted to adopt a child how important would it be to know the child's genetic makeup?
4. What convinced members of the United States Congress to use IQ scores as the bias for immigration laws?
5. Would brain scans provide a less biased, more culture-free measure of intelligence than standard IQ tests? 
                 Topics in Psychology
                      Robert C. Gates