Intelligence and
Individual Testing
Differences
AP Psychology
Standardization & Norms
 Psychometrics: the measurement of mental traits,
abilities, & processes.
 Psychometricians: involved in test development in
order to measure some CONSTRUCT or behavior that
distinguishes people from one another.
Constructs: ideas that help summarize a group of
related phenomena or objects
 Constructs are useful for understanding, describing,
& predicting behavior.
 Psychological tests measure abilities, interests,
creativity, personality, & intelligence.
Standardization & Norms (cont’d)
 Standardization: two part test development procedure:
 First establishes test norms from the test results of a
large representative sample
 Ensures that the test is both administered & scored
uniformly for all test takers
 Norms: scores established from the test results of the
representative sample and used as a standard to
compare scores of other test takers.
 When administering a standardized test, all proctors
must provide the same directions, time limits, &
conditions as other proctors. Scorers must use the
same scoring system, applying the same standards to
rate responses.
Reliability & Validity
 Reliability: consistency of test results over time
(repeatability) as long as all other variables remain the
same.
 Test-retest method: the same exam is administered to
the same group on two different occasions & the scores
are compared.
• the closer the coefficient is to 1, the more reliable
the test
• Problem: familiarity when taking the test for the
second time may skew results.
 Spilt-half method: the score from the first half of the
test is compared to the score on the last half of the test
to see if they are consistent.
Reliability & Validity (cont’d)
 Alternate form method (equivalent form method: two
different versions of a test on the same material are
given to the same test takers, and the scores are
correlated.
 Interrater Reliability: the extent to which two or more
scorers evaluate responses in the same way.
 Validity: the test accurately measures what it is supposed
to measure.
 Face Validity: measure of the extent to which the
content of the test measures all the knowledge and/or
skills that are supposed to be included within the
domain of that test, according to the test takers.
Reliability & Validity (cont’d)
 Content Validity: a measure of the extent to which the
content of the test measures all of the knowledge &/or
skills to be included within the domain being used,
according to expert judges.
 Criterion Related Validity: a measure of the extent to
which a test’s results correlate with other accepted
measures of what is being tested.
 Predictive Validity: a measure of the extent to which the
test accurately forecasts a specific future result.
• Ex: high SAT scores should predict high grades for the first
year of college.
 Construct Validity: the extent to which the test actually
measures the hypothetical construct or behavior it is
designed to test. Often considered the true measure of
validity.
Types of Tests
Performance Tests
 Include SATs, AP tests, Wechsler Intelligence tests, StanfordBinet intelligence tests, and most classroom tests.
 The test-takes know what he/she should do in response to
questions or tasks on the test & it is assumed that the test
taker will do the best he/she can do to succeed.
Observational Tests
 The test-taker does NOT have a single well-definied task to
perform.
 Assessed on typical behavior or performance in a specific
context.
 Include employment interview, & formal on-the-job
observations for evaluation.
Types of Tests (cont’d)
Self-Report Tests
 require the test taker to describe his/her feelings, attitudes,
beliefs, values, opinions, physical &/or mental state on
surveys, questionnaires, or polls. Includes the MMPI-2
(personality test)
 Performance Tests in which there is a correct answer can be
divided into:
 Speed Tests: generally include a large number of relatively
easy items administered with strict time constraints under
which most test takers find it impossible to complete.
Power Tests: provide the test taker with enough time to
compete items of varying difficulty. Differences in scores
among test takers reflect knowledge & perhaps good
guessing.
Types of Tests (cont’d)
 Aptitude Tests: type of ability test that predict a person’s
future performance or to assess the person’s capacity to
learn
 Achievement Tests: type of ability test that assesses what
a person has already learned
 Interest Tests: use a person’s descriptions of his/her own
interests to predict vocational adjustment and satisfaction
 Strong-Campbell Interest Inventory: most widely used
vocational interest test
 Personality Tests: standardized tasks designed to
determine various aspects of personality or the emotional
status of the individual examined
Types of Tests (cont’d)
 Group Tests: test many people at once; the test taker
works alone. These tests are cheaper to administer and
more objective in scoring.
 Examples include SAT, ACT, AP exams
 Individualized Tests: interaction of one examiner with
one test takers. Such tests are expensive and involved
subjective grading.
 Examples include Wechsler Adult Intelligence Scale-III and
Standford-Binet Intelligence Scales
Ethics & Standards in Testing
 The American Psychological Association (APA) & other
guidelines detail standards to promote the best
interests of the client, guard against misuse, and
respect the client’s right to know results and safeguard
dignity.
 Culture-relevant tests: test skills and knowledge
related to cultural experiences of the test takers.
Intelligence
 “Intelligence is operationally defined as the global capacity
of the individual to act purposefully, to think rationally, and to
deal effectively with his/her environment” (David Wechsler)
 Measurement of Psychophysical Performance (Francis
Galton):
measured psychomotor tasks to gauge intelligence
 reasoned that people with excellent physical abilities are
better adapted for survival and therefore highly intelligent.
 James McKeen Cattell brought Galton’s studies to the US,
measuring strength, reaction time, sensitivity to pain, &
weight discrimination – collectively called “mental test”
 Correlated poorly with reasoning ability, but brought
attention to the systematic study of measuring cognitive &
behavioral differences.
Intelligence (cont’d)
 Measurement of Judgment (Alfred Binet)
thought intelligence could be measured by sampling
performance of tasks that involved memory, comprehension &
judgment.
 Collaborated with Theodore Simon to create the Binet-Simon
Scale which was meant to only be used for class placement.
 Binet believed that child the age of 6 answers questions
differently that a child of 8, so based on responses on the
Binet-Simon Scale, children were given a mental age (mental
level) reflecting the age in which typical children give those
same responses.
 Because mental age could be misleading, William Stern
(German psychologist) suggested using the ratio of mental
age (MA) to chronological age (CA) to determine a child’s
intelligence.
Intelligence (cont’d)
 Mental Age and Intelligence Quotient
 Lewis Terman adapted Binet’s scale for the US, calling it
the Standford-Binet Intelligence Scale
 The scale score is reported as IQ, which is the child’s
MA/CA X 100.
For adults, IQ is meaningless and is determined by the
derivation IQ determined result of the standardizing
process for a particular test.
• The Fifth Edition Standford-Binet IQ Test for Adults has
been standardized with a representative group up to
age of 90
• Fluid reasoning, visual-spatial processing, working
memory, and quantitative reasoning peak the 30s;
knowledge peaks in the 50s.
Intelligence (cont’d)
The Wechsler Intelligence Scales (David Wechsler)
 Aged based Intelligence Scales including:
 WPPSI (Wechsler Preschool & Primary Scale of
Intelligence)
WISC (Wechsler Intelligence Scale for Children 6-16)
 WAIS (Wechsler Adult Intelligence Scale for older
adolescents and adults)
 WAIS-III (latest version) has a verbal scale with items on
comprehension, vocabulary, information, similarities,
arithmetic, and digit span and a performance scale with
items dealing with object assembly, block design, picture
completion, picture arrangements, & digit symbols.
Scores are based on deviation IQ (how spread out the
scores were from the mean of 100).
68% of the population has an IQ between 85 and 115
(considered low normal to high normal in intelligence.
Intelligence (cont’d)
 Test takers who fall 2 SD (standard deviation) below the
mean are considered borderline for mental retardation
(70); those who score 2 SD above the mean (130) are
sometimes considered mentally gifted.
 Those with scores 3 SD above the mean (145) are
sometimes considered to be geniuses.
 These scales are judged to be more helpful to determine
extremes of intelligence than the Standford-Binet Scale.
 They also are helpful in identifying possible learning
disabilities when a child’s performance IQ is very
different from his/her verbal score.
Intelligence (cont’d)
Cognitively Disabled (Mental Retardation)
 IQ score at or below 70 and show difficulty adapting to
everyday life
 Mildly cognitively disabled individuals score between
50 to 70 on IQ tests and are usually capable of taking
care of themselves, their homes, achieve a 6th grade
education, hold a job, get married and have children.
Such children are often mainstreamed (integrated into
regular education classes)
 Moderately cognitively impaired individuals score between
35-49 on IQ exams, may achieve a 2nd grade level, given
training in skills such as eating, toileting, hygience,
dressing, and grooming in order to care for themselves,
and given life skills training so they can hold down menial
jobs and live in group homes.
Intelligence (cont’d)
 Severely cognitively challenged individuals have scores
or 20-34 on IQ tests, have a limited vocabulary, and learn
limited self-care skills. They are usually unable to care for
themselves and do not develop enduring friendships.
 Profoundly mentally challenged individuals with IQ
scores below 20 need custodial care.
 Today, communities are housing a greater proportion of
cognitively disabled people than in the past.
Many live with their own families or in group homes
when possible.
 This deinstitutionalization is called normalization.
Kinds of Intelligence
 Factor Analysis (Charles Spearman)
 tested a large number of people on a number of
different mental tasks and used the statistical
procedure of factor analysis to determine closely
related clusters of factors among the groups of items
by identifying variables with high degrees of
correlation.
Single Factor Intelligence Theory:
• Determined that one factor g, underlies all
intelligence (because all mental tasks he tested had
a high degree of correlation).
• Also identified the s factor that was important for
special abilities.
Kinds of Intelligence (cont’d)
Spearman’s work was disputed by Louis Thurstone
who used factor analysis to examine tests of college
students.
 Identified 7 distinct factors he termed primary
mental abilities which included:
-- inductive reasoning, word fluency, perceptual
speed, verbal comprehension, spatial visualization,
numerical ability, & associative memory.
 John Horn & Raymond Cattell determined that
Spearnan’s g should be subdivided into two factors of
intelligence – fluid intelligence and crystallized
intelligence
Multiple Intelligences
 Howard Gardner: Theory of Multiple Intelligences
 Savants, individuals otherwise considered cognitively
challenged, have a specific exceptional skill typically in
calculating, music, or art, were an indication to Gardner
that a single g factor does NOT underlie intelligence.
 Believe in the existence of 8 intelligences
• Three are measured on traditional intelligence tests:
logical-mathematical, verbal-linguistic & spatial
• Five are not: musical, bodily-kinesthetic, naturalistic,
intrapersonal, & interpersonal. According to Gardner,
these abilities also represent ways people process
information differently.
 Gardner’s theory has led to changes in how some
schools classify gifted and talented children for special
programs.
Multiple Intelligences (cont’d)
Emotional Intelligence (Salovey & Mayer)
 The ability to perceive, express, understand, & regulate
emotions.
 Combines Gardner’s interpersonal & intrapersonal
intelligences
 MEIS Multifactor Emotional Intelligence Scale (Salovey,
Mayer, & Caruso): developed to measure emotional
intelligence
Multiple Intelligences (cont’d)
Triarchic Theory of Intelligence (Robert Sternberg)
 Three distinct intelligences that include:
 Analytical Thinking: compare, contrast, analyze, &
figure out cause and effect relationships
 Creative Intelligence: evidenced by adaptive reactions
to novel situations, showing insight, and being able to
see multiple ways to solve a problem.
 Practical Intelligence: includes “street smarts” such as
being able to read people, being able to get to a distant
location or organizing an event. (also known as
emotional or interpersonal intelligence)
• Such people with practical intelligence often succeed in
careers, marriages, & parenting, where people with
higher IQ but less emotional intelligence fail.
Creativity
 defined as the ability to generate ideas and solutions that
are original, novel, and useful, is not usually measured by
intelligence tests.
 Threshold Theory: a certain level o f intelligence is
necessary but not sufficient for creative work.
 There are tests for creativity such as the Torrance Test of
Creative Thinking, the Christensen-Guilford Test, the
Remote Associates Test, and the Wallach & Kogan
Creative Battery, however, none have criterion-related
validity.
 On Intelligence tests: most psychometricians &
psychologists agree that intelligence tests measure the
ability to take tests well; they disagree that such tests
actually measure intelligence.
 Since results of intelligence tests correlate highly with
achievement, they do have predictive ability.
Heredity/Environment &
Intelligence
 Down’s Syndrome: cognitive impairment from genetic
defects (nature)
 FAS (Fetal Alcohol Syndrome): mental retardation of
child as a result to prenatal exposure to alcohol
(primarily environmental)
 PKU (Phenylketonuria): cognitive disability due both
nature and nurture
 Cultural-Familial Retardation: About 75% of all cases of
cognitive impairment result from sociocultural
deprivation in an impoverished environment,
Twin Studies
 Studies to gauge the influence of genes on intelligence
including comparing the intelligence test scores of
identical twins reared together with scores from
fraternal twins.
 Such studies show that identical twins have much
higher scores.
 Even when reared apart, identical twins evidence
similar intelligence score that even closer with age.
 Intelligent scores of adoptees are more similar to their
biological parents than adopted parents & become
more similar with age.
 Brain scans of identical twins reveal similar brain
volume & anatomy.
Environmental Influences on
Intelligence
 Siblings raised together are more similar in IQ than those
raised apart.
 The IQs of children from deprived environments who
move into middle or upper-class foster or adoptive
families tend to show increases.
 The Flynn Effect: steady increase in performance on IQ
tests over the last 80 years, possibly resulting from better
nutrition, educational opportunities, and health care
(favors nurture)
 Heritability: for intelligence for individuals ranges from
50-75%. (proportion of variation among individuals in a
population that results from genetic causes).
 Reaction Range Model: genetic makeup determines the
upper limit for an individual’s IQ; the lower limit results
from an impoverished environment.
Human Diversity
 Racial differences in IQ scores indicate that African
Americans, Native Americans, and Hispanic
Americans typically score 10-15 points below the
mean for Caucasian American children.
 Researchers suggests that differences between the
mean scores of two different groups could be caused
entirely by environmental factors.
 Stereotype Threat: part of the difference in IQ scores
may be attributed to the anxiety that influences
members of a group concerned that their performance
on a test will confirm a negative stereotype.