Assessing Intelligence
RG 11b
Assessing Intelligence
Psychologists define intelligence testing as a
method for assessing an individual’s mental
aptitudes and comparing them with others using
numerical scores.
Alfred Binet
Alfred Binet and his
colleague Théodore
Simon developed the first
standardized intelligence
test…they were
commissioned by the
French government to
design a “test” to identify
French children who
would have problems in
regular classes
Binet
Set out to find a child’s mental age, or the average
age of individuals who achieve a particular level of
performance
Binet did not create the test to LABEL children…he
actually warned that if the information were misused
it would do just this…instead he wanted only to find
a way to help improve the educational experience
of French children
Lewis Terman
Lewis Terman, in the
US, adapted/revised
Binet’s test for American
school children and
named the test the
Stanford-Binet IQ Test.
(he worked at Stanford)
A form of the StanfordBinet is still in use
today…
Stanford-Binet
Today…the Stanford-Binet is given orally and varies in
nature according to the person taking the test
● Children – given figures to copy or everyday problems to
solve
● Adults – asked to solve analogies, explain proverbs and
describe similarities that underlie sets of words
The examiner begins by finding a mental age at which
person can answer all questions…move on to more difficult
problems…when mental age is reached at which no items
can be answered, test is over
William Stern
The formula of
Intelligence Quotient (IQ)
introduced by William
Stern is:
Example…
IQ is no longer computed
this way…
David Wechsler
Wechsler developed the
Wechsler Adult
Intelligence Scale
(WAIS) and later the
Wechsler Intelligence
Scale for Children
(WISC), an intelligence
test for preschoolers –
they are the most widely
used IQ tests today.
WAIS
WAIS measures overall intelligence – consists of
2 parts, verbal and performance
Verbal – vocab definitions and comprehension
Performance – timed assembly of small objects
and arranged pictures in logical order
Normally verbal and performance are within close
range, yet separate scores can give a more
precise picture of a person’s specific abilities
WAIS example
Aptitude and Achievement Tests
Achievement tests are intended to reflect what you
have already learned – current level of knowledge
Examples??
Aptitude tests are intended to predict your ability to
learn a new skill – how well you could do
Examples???
What is your opinion of aptitude tests? Do they prove
what they say they are measuring?
D. Flynn
While Thurstone, Gardner, Sternberg, and
Goleman all tried to define intelligence,
Flynn is know for his observation that
intelligence, as measured by IQ tests, is
increasing.
●What theories does each theorist argue?
●What about Spearman?
●
Principles of Test Construction
For a psychological test to be acceptable it must
fulfill three criteria:
●
●
●
Standardization
Reliability
Validity
Standardization
Standardization = test items piloted on a similar
population of people and “norms” have been
established
 Norms are developed by calculating the average
score achieved by a particular group and then each
person’s score can be compared to see how it differs from
people who have taken the test in the past
●
EX: AP test given to college freshman as a final exam
to set norms (known as the standardization sample).
 periodically tests are re-standardized – given to a random,
representative sample to reset/check the established
norms (including intelligence tests whose “normal” score is
100).
Normal Curve
Standardized tests establish a normal distribution
of scores on a tested population — a bell-shaped
pattern called the normal curve.
Flynn Effect
In the past 60 years intelligence scores have
steadily risen by an average of 27 points — a
phenomenon known as the Flynn effect.
Why do you think this has happened????
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.
●
Reliability using different tests: Using different
forms of the test to measure consistency between them.
●
Test-Retest Reliability: Using the same test on two
occasions to measure consistency.
●
Validity
Reliability of a test does not insure 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.
●
Reliability of a test does not insure validity...in other words,
a test can be consistent without testing what it is
supposed to test!
Is intelligence fixed or does it
change over time?
It depends on the type of intelligence…
Fluid intelligence – reflects information-processing
capabilities, reasoning and memory
●
tends to decline as we age
●
Crystallized intelligence -- accumulated knowledge,
skills and strategies that have been learned through
experience
●
tends to increase throughout life
●
So… a 70-year-old may have more crystallized intelligence than
a 30-year-old, but his processing will definitely be slower,
which could make it look like he has less intelligence.