lecture 11 from a college level introduction to psychology course taught Fall 2011 by Brian J. Piper, Ph.D. (psy391@gmail.com) at Willamette University, includes Binet, Terman, Wechsler, WAIS, reliability, validity, norms

1. Intelligence
Brian J. Piper, Ph.D.

2. Assessing Intelligence
 The Origins of Intelligence Testing
 Modern Tests of Mental Abilities
 Principles of Test Construction
The Dynamics of Intelligence
 Extremes of Intelligence

3. Assessing Intelligence
Psychologists define intelligence testing as a
method for assessing an individual’s mental
aptitudes and comparing them with others using
numerical scores.

4. Alfred Binet
Alfred Binet and his
colleague Théodore
Simon practiced a more
modern form of
intelligence testing by
developing questions
that would predict
children’s future
progress in the Paris
school system.
1857-1911

5. Definition of Intelligence
• "It seems to us that in intelligence there is a fundamental faculty, the
alteration or the lack of which, is of the utmost importance for practical life.
This faculty is judgment, otherwise called good sense, practical sense,
initiative, the faculty of adapting one's self to circumstances. A person may
be a moron or an imbecile if he is lacking in judgment; but with good
judgment he can never be either. Indeed the rest of the intellectual faculties
seem of little importance in comparison with judgment" (Binet & Simon,
1916, 1973, pp.42-43)

6. Alfred Binet
Normal versus
Abnormal
Environmentalist
1857-1911

7. Lewis Terman
In the US, Lewis Terman
adapted Binet’s test for
American school
children and named the
test the Stanford-Binet
Test. The following is the
formula of Intelligence
Quotient (IQ),
introduced by William
Stern:
1857-1936

8. Lewis Terman
• Eugenics
• Quantitative
1857-1936
Eugenics (9.5 min, 1st 2 best):
http://www.youtube.com/watch?v=ufqOe0_pres

9. David Wechsler
Wechsler developed the:
Wechsler Adult Intelligence Scale (WAIS): 1939, 16+
Wechsler Intelligence Scale for Children (WISC)
1949, 6-16
Wechsler Preschool & Primary School Scale of
Intelligence, 1967, Ages: 2.5 - 7
1896 – 1981

10. Intelligence
• the global capacity to act purposefully, to
think rationally, and to deal effectively with
[one's] environment

11. WAIS
WAIS measures overall intelligence and 11 other
aspects related to intelligence that are designed to
assess clinical and educational problems.

12. WASI Exercise

13. Principles of Test Construction
For a psychological test to be acceptable it must
fulfill the following three criteria:
1. Standardization
2. Reliability
3. Validity

14. Standardization
Standardizing a test involves administering the test
to a representative sample of future test takers in
order to establish a basis for meaningful
comparison.
Representative: Age, Ethnicity, Sex

15. Normal Curve
Standardized tests establish a normal distribution
of scores on a tested population in a bell-shaped
pattern called the normal curve.

16. Flynn Effect
In the past 60 years, intelligence scores have risen
steadily by an average of 27 points. This
phenomenon is known as the Flynn effect.

17. Reliability
A test is reliable when it yields consistent results. To
establish reliability researchers establish different
procedures:
 Split-half Reliability: Dividing the test into two
equal halves and assessing how consistent the
scores are.
 Test-Retest Reliability: Using the same test on two
occasions to measure consistency.

18. Validity
Validity of a test refers to what the test is supposed
to measure or predict.
 Content Validity: Refers to the extent a test
measures a particular behavior or trait.
 Predictive Validity: Refers to the function of a test
in predicting a particular behavior or trait.
GRE & GPA

19. Extremes of Intelligence
A valid intelligence test divides two groups of
people into two extremes: the mentally retarded (IQ
70) and individuals with high intelligence (IQ 135).
These two groups are significantly different.

20. High Intelligence
Contrary to popular belief, people with high
intelligence test scores tend to be healthy, well
adjusted, and unusually successful academically.

21. Mental Retardation
Mentally retarded individuals required constant
supervision a few decades ago, but with a
supportive family environment and special
education they can now care for themselves.

22. Mental Retardation: High
dose Fetal Alcohol

23. Autism
• Neurodevelopmental
disorder
• Prevalence: 0.2%
• Symptoms
– Social
– Communication
– Self-stimulation

24. Savant
• Steven Wiltshire
• http://www.youtube.com/watch?v=ckqDX2XpdyY
1974 -

25. Summary
• Intelligence tests have a long history (Binet
versus Terman)
• Test Characteristics
– Reliability
– Validity