TESTING AND INDIVIDUAL
DIFFERENCES
Modules 30-32
MEASURING INDIVIDUAL
DIFFERENCES

Psychology relies heavily on testing individuals, it is part
of the foundation for psychological analysis. To be
effective, however, strict guidelines must be followed.

Validity: Does the test actually measure what we say it
does/what we want it to?
Ex. Reading on a math test
 Face validity: Does the test look like it tests what it is supposed to
test?
 Content validity: Each part of the test is representative of the larger
body of knowledge.

MEASURING INDIVIDUAL DIFFERENCES
Criterion Validity: The behavior (such as college
grades) that a test (such as the SAT) is designed to
predict
Predictive Validity: The success with which a test
predicts the behavior it is designed to predict.
ASSESSING INTELLIGENCE
Football 10
linemen’s 9
success
Greater correlation
over broad range
of body weights

8
7
6
5
Little correlation within
restricted
range
4
3
2
1
0
180
250
290
Body weight in pounds
As the range of data
under consideration
narrows, its
predictive power
diminishes
MEASURING INDIVIDUAL
DIFFERENCES
 The

second part of a credible test is reliability.
Reliability: A test yields the same results over time

Test-Retest or Split-Half Reliability
Reliable, but not
valid
Not reliable, not
valid
Reliable and
valid
CREATING VALIDITY AND RELIABILITY
The most efficient way to create validity and
reliability is to use a standardized test.
 In the most basic sense, a standardized test
means:

The administration and scoring is the same for each
test
 The results of the test can be used to draw a
conclusion about the test takers in regard to the
objectives of the test.


Ex. AP test, S.A.T.
JUDGING NORMAL

A “normal curve” is applied to test to
determine establish “norms.” When a
statistically significant sample of the
population has been tested, strong
conclusions can be drawn.

A normal range for IQ scores is 70-130.
Scores below 70 indicate mental
retardation while scores above 130 are
considered gifted.
NORMAL DISTRIBUTION OF IQ
SCORES
DEGREES OF MENTAL RETARDATION
TYPES OF TESTS

There are two main types of tests:
1.
Objective Tests: Tests that have one set answer, that can be
scored easily by machine

1.
Ex. Multiple choice
Subjective Tests: Tests in which individuals are given
ambiguous figures or an open ended question which requires
some interpretation and analysis.

Ex. FRQs
 Inter-rater reliability
SAMPLE SUBJECTIVE TEST

The Rorschach Inkblot Test is one of the most widely
known, and inaccurate subjective tests.

The following slides are real inkblots from the test that
was, at one time, a widely used test. Today, it has lost
much, if not all of its credibility in determining
intelligence or mental illness.
INTELLIGENCE TESTING
A term that is used frequently, but often misunderstood is
“intelligence.” What exactly is intelligence?
 Many people disagree about what exactly intelligence is,
but most do agree that it is:

Relative: defined in relation to the same abilities in a
comparison group (usually age)
 Hypothetically constructed: it is unobservable, but instead
inferred from behavior

TESTING IQ

IQ (intelligence quotient)
became a popular way to
classify people in the early
1900s when two French
psychologists (Alfred Binet and
Theodore Simon) developed a
test to identify those students
who were gifted, and those who
needed extra help.
BINET-SIMONTEST

The test had four important distinctions:
Scores were interpreted at their current performance
 Used to identify students in need of help, not label them or
categorize them
 Emphasized that training and opportunity could affect intelligence
 Was empirically constructed


Scoring the test was done by calculating the mental age
(MA) and the chronological age (CA).
MA= The average age at which normal individuals achieve a
particular score
 CA= The number of years since an individuals birth

COMING TO AMERICA

The idea of IQ testing became popular in America for
three reasons:
A huge increase in immigration
 New laws requiring universal education
 Military assessing new recruits for WWI


It created an inexpensive and objective way to separate those
could benefit from education or military leadership training
and those who needed assistance.
DOWNSIDE OF IQ TESTING
Despite its utility, IQ testing had a big downside. Tests
ended up reinforcing prevailing prejudices about race
and gender.
 Ignored was the fact that environmental disadvantages
limit the full development of people’s intellectual
abilities.

STANFORD-BINET INTELLIGENCE
SCALE

When the Binet test was adopted by a Stanford professor,
he changed the equation to make intelligence scores into
non-decimal numbers. This now became known as the
Intelligence Quotient (IQ).
=IQ
COMPONENTS OF INTELLIGENCE

Savant Syndrome: Individuals with remarkable, but rare
talent, even though they are mentally deficient in other
areas.

Ex. Dustin Hoffman in Rain Man
THEORIES OF INTELLIGENCE
Spearman’s g Factor: Charles Spearman thought
intelligence was a general factor behind all of our mental
ability.
 Sternberg’s Triarchic Theory (CAP)
 Catell’s Fluid and Crystallized Intelligence


The g factor
THEORIES OF INTELLIGENCE

Howard Gardner believed that IQ scores measured only
a limited range of human mental abilities. He argued we
have seven separate mental abilities he calls the
multiple intelligences.







Linguistic intelligence ("word smart"):
Logical-mathematical intelligence ("number/reasoning
smart")
Spatial intelligence ("picture smart")
Bodily-Kinesthetic intelligence ("body smart")
Musical intelligence ("music smart")
Interpersonal intelligence ("people smart")
Intrapersonal intelligence ("self smart")