Chapter 11 pt. 2:
Intelligence Assessment
Assessing Intelligence:
Aptitude vs. Achievement
Test
 Aptitude
Tests: are tests designed
to predict a person’s future
performance.
 SAT’s and GRE’s
 Achievement Test: a test designed
to assess what a person has
learned.
 Midterm Psych exam, chapter 3
history test, etc.
Assessing Intelligence
 Wechsler
Adult Intelligence
Scale (WAIS)
 most widely used intelligence
test
 subtests
verbal
performance (nonverbal)
Also a WISC (Wechsler
Intelligence Test for Children).
Assessing Intelligence- Sample
Items from the WAIS
VERBAL
PERFORMANCE
General
Information
Similarities
Arithmetic
Reasoning
Vocabulary
Comprehension
Digit Span
Picture Completion
Picture
Arrangement
Block Design
Object Assembly
Digit-Symbol
Substitution
WAIS SAMPLE
Qualities of A Good Test
To be accepted all psychological
tests must be:
1. Standardized
2. Reliable
3. Valid

Standardization
Standardization: defining meaningful scores
by comparison with the performance of a
pretested group.
 Your scores are compared with the
pretested group who took the test.
 Standardized tests usually follow a normal
distribution.
 Normal Distribution: bell shaped curve that
describes the distribution of many physical and
psychological properties. Most scores fall
near average, and fewer and fewer scores
lie near the extreme.

The Normal Curve (Know My
Distributions)
Number
of
scores
Sixty-eight percent
of people score
within 15 points
above or below 100
Ninety-five percent
of all people fall
within 30 points
of 100
55
70
85
100
115
130
145
Reliability vs. Validity (DON’T MIX
THEM UP)

Reliability deals with consistency.
assessed by consistency of scores on:
two
halves of the test
alternate forms of the test
retesting the same individual
 Weschler and Standford Binet test +.9
 Validity deals with predictability. Does the
test measure what it is supposed to measure?
Types of Validity
 Content
Validity: the extent to which a
test samples the behavior that is of
interest.Would a maneuverability test on
a skateboard have content validity for
testing to see if your qualified to drive?
 Predictive Validity: The success with
which a test predicts the behavior it is
supposed to predict.
 Do high SAT scores correlate with high
college grades?
Predictive Validity is Based on
Criterion
 Criterion:
the behavior that a test is
supposed to predict. Is used to see
if test is successful.
 What would the criterion be for the
GRE’s?
The Flynn Effect
 Since the advent of intelligence
tests, people’s IQ scores have
been improving with time (flynn
effect).
 If standardized with today’s tests,
scores 80 years ago would have a
average IQ of 76.
 Possible Causes?
The Flynn Effect
IQ105
scores
100
95
90
85
80
75
70
1910
1930
1950
Year
1970
1990
Stability of Change?
 Can
infant tests predict future
intelligence?
 Picture
Test
 Starting at Age 4 may predict future
IQ
 Age 7 scores become stable,but not
fixed
Low Extreme of Intelligence
 Mental
Retardation: condition of
limited mental ability, indicated by an
intelligence score of below 70 and
difficulty adapting to the demands of life.
Low Extreme of Intelligence
 Down
Syndrome: condition of
retardation and associated
physical disorders caused by an
extra chromosome in one’s
genetic makeup.
 Many mentally retarded people
with Down Syndrome can adapt
to disorder and some have
earned college degrees with
accomdations…nearly all learn
how to read.
Degrees of Mental Retardation
Degrees of Mental Retardation
Level
Typical Intelligence Scores
Percentage of the Retarded
Adaptation to Demands of Life
Mild
50-70
85%
Most learn academic skills up to
sixth-grade level. Adults may, with
assistance, achieve self-supporting
social and vocational skills.
Moderate
35-49
10
May progress to second-grade level.
academically. Adults may contribute
to their own support by labor in
sheltered workshops.
Severe
20-34
3-4
May learn to talk and perform simple
work tasks under close supervision
but are generally unable to profit from
vocational training.
Gifted
 Smart
kids are usually
not “weird”
 Tend to get higher
degrees
 Should gifted children
be “tracked” in
school?
Is Intelligence Genetic or
Environmental?
 Influenced
Similarity of 1.0
intelligence 0.9
scores
(correlation) 0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Identical
twins
reared
together
Identical
twins
reared
apart
Fraternal Siblings Unrelated
reared individuals
twins
together reared
reared
together
together
by both,
but the
most
genetically
similar
have the
most
similar
scores.
Genetic Influences
 With
age, genetic influences become
more apparent.
 Adopted children’s intelligence scores
become more like their biological
parents, and identical twins similarities
continue to increase as they age.
 Still hard to tell what percentage of
intelligence comes from genes to account
for differences between people
(heritability).
Genetic Influences
0.35
Child-parent
correlation in
verbal ability
scores
0.30
0.25
Children and their
birth parents
0.20
0.15
Adopted children
and their birth
parents
0.10
Adopted children
and their adoptive
parents
0.05
0.00
3 years
16 years
Environmental Influences
Early
Intervention
Head
Start
Schooling
Effects
Schooling
and IQ scores
tend to correlate
Schooling Effect
118
IQ gains relative 115
to grade 4
baseline 112
Grade 6
109
106
Grade 5
103
100
Grade 4
97
110
115
120
125
130
135
Age in months
140
145
150
Group Differences in IQ Scores
 Ethnic
Similarities and Differences
 Racial
groups differ in IQ scores
 Higher scoring ppl and groups tend to have
higher incomes and education
 Individual differences within a race are much
greater than differences between races
 Asian students outperform North American
student on math tests
 IQ scores have increased
 White and blacks tend to score the same on
infant IQ tests
Group Differences in Intelligence
Scores Are Probably Mostly
Attributed to the Environment
Variation within group
Variation within group
Seeds
Poor soil
Fertile soil
Difference within group
Group Differences in IQ Scores
Gender Similarities and Differences
 No big differences
 Girls are better spellers, more verbal, more
sensitive to senses
 Boys tend to be in lower classes more and talk
later and stutter more
 Math and Spatial Aptitudes
No huge differences
Boys tend to do a bit better on math
Girls better on memory and picture
recognition
 Women better at reading facial expressions

The Question of Bias
2 definitions
1. Tests detect not only innate
differences in IQ but also differences
caused by cultural experiences
 Yes.
Test do not account for
differences in cultures, which may
make them bias
2. Is a test less valid for some groups
than for others.
 No.
The predictive value of a
standard IQ testS is roughly the
same for black and whites and rich
and poor…….
The Question of Bias
 Stereotype
Threat
A
self confirming concern that
one will be evaluated based on
a negative stereotype
Black
student's taking verbal test
Women and math scores