Chapter 9: Intelligence and Psychological Testing
The vast enterprise of modern testing evolved from psychologists‟ pioneering efforts to measure
A psychological test is a standardized measure of a sample of a person‟s behaviour
(measurement instruments). They are used to measure the individual differences that exist among
people in abilities, aptitudes, interests, and aspects of personality.
Sample: responses to a psychological test represent a sample of your behaviour (one of the key
limitations of psychological test and show always be interpreted cautiously).
Intelligence tests measure general mental ability
Aptitude tests assess specific types of mental abilities. They are also designed to measure
potential more than knowledge, but they break mental ability into separate components.
Differential Aptitude Tests assess verbal reasoning, numerical ability, abstract reasoning,
perceptual speed and accuracy, mechanical reasoning, space relationships, spelling, and language
Achievement tests: gauge a person‟s mastery and knowledge of various subjects such as reading,
English or history). They are like aptitude tests, have a specific focus, but they‟re supposed to
measure previous learning instead of potential.
Personality tests: measure various aspects of personality, including motives, interests, values and
attitudes. They assess traits systematically. Many psychologists prefer to call these tests
personality scales because unlike test of mental abilities, the question do not have right and
Standardization and Norms:
Standardization refers to the uniform procedures used in the administration and scoring of a test.
Both personality scares and tests of mental abilities are standardized measure of behaviour.
Test norms: provide information about where a score on a psychological test ranks in relation to
other scores on that test (tell you how you score relative to other people).
Percentile score: indicates the percentage of people who score at or below the score one has
Standardization group: sample of people that the norms are based on
Reliability: refers to the measurement consistency of a test (or of other kinds of measurement
Test-retest reliability (estimated by comparing subjects‟ scores on two administrations of a test) A correlation coefficient: a numerical index of the degree of a relationship between two
Validity: refers to the ability of a test to measure what it was designed to measure. The term
„validity‟ is also used to refer to the accuracy or usefulness of the inferences or decisions based
on a test.
Content validity: refers to the degree to which the content of a test is representative of the
domain it‟s supposed to cover.
Criterion-related validity: estimated by correlating subjects‟ scores on a test with their scores on
an independent criterion (another measure) of the trait assessed by the test.
Hypothetical constructs: abstract qualities (creativity, intelligence, extraversion or independence)
Construct validity: the extent to which there is evidence that a test measures a particular
Galton‟s Studies of Hereditary Genius:
He assumed that the contents of the mind are built out of elementary sensations, and he
hypothesized that exceptionally bright people should exhibit exceptional sensory acuity.
Coined the phrase „nature verses nurture” to refer to the heredity-environment issue
Also invented the concepts of correlation and percentile test scores
Mental age: indicated that he or she displayed the mental ability typical of a child of that
chronological (actual) age.
Intelligence quotient (IQ): a child‟s mental age divided by chronological age, multiplied by 100.
Scores on intelligence test are no longer based on an actual quotient.
Intelligence tests today: (fall into two categories)
Normal distribution: a symmetric, bell-shaped curve that represents the pattern in which many
characteristics are dispersed in the population.
Deviation IQ scores: locate subjects precisely within the normal distributions, using the standard
deviation as the unit of measurement.
The key point is that modern IQ scores indicate exactly where you fall in the normal distribution
People‟s backgrounds differ and it‟s not easy to devise items that are completely unaffected by
differences in knowledge. Test developers try to circumvent this problem by requiring subjects to apply relatively common knowledge. Hence, IQ tests measure a blend of potential and
Examples of intelligent behaviour fell into three categories:
People who score high on IQ tests are more likely than those who score low to end up in high-
status jobs. There is far more debate about whether IQ scores are effective predictors of
performance within a particular occupation.
Extremes of Intelligence
Mental retardation or intellectual disability: refers to subnormal general mental ability
accompanied by deficiencies in adaptive skills, originating before age 18.
Down syndrome: a conditioned marked by distinctive physical characteristics (such as slanted
eyes, stubby limbs, and thin hair) that is associated with mild to severe retardation.
Fragile X syndrome (FXS): A common cause of hereditary mental retardation.
Phenylketonuria: a metabolic disorder (due to an inherited enzyme deficiency) that can lead to
intellectual disability if it is not caught and treated in infancy.
Hydrocephaly: an excessive accumulation of cerebrospinal fluid in the skill destroys brain tissue
and causes retardation.
Gifted children have long been stereotyped as weak, sickly, socially inept “bookworms” who are
often emotionally troubled. The empirical evidence largely contradicts this view.
Heredity and Environment as Determinants of Intelligence:
Family studies: can determine only whether genetic influence on a trait is plausible, not whether
it is certain. Family members share not just genes, but similar environments. If high intelligence
(or low intelligence) appears in a family over several generations, this consistency could reflect
the influence of either shared genes or shared environment. Because of this problem, researchers
must turn to twin studies and adoption studies to obtain more definitive evidence on whether
heredity affects intelligence. Although reared in different environments, these identical twins still
display greater similarity in IQ (average correlation: O.72) than fraternal twins reared together
(average correlation: 0.60).
Heritability ratio: an estimate of the proportion of trait variability in a population that is
determined by variations in genetic inheritance. Cumulative deprivation hypothesis: children who are raised in substandard circumstances
should experience a gradual decline in IQ as they grow older (since other children will be
progressing more rapidly).
Reaction range: refer to these genetically determined limits on IQ (or other traits).
There is relatively little argument about the existence of these group differences, variously
referred to as racial, ethnic, or cultural differences in intelligence.
Stereotype vulnerability: derogatory stereotype of stigmatized groups‟ intellectual capabilities
create unique feelings of vulnerability in the educational arena. These feelings of stereotype
vulnerability can undermine group members‟ performance on tests, as well as other measures of
academic achievement. These feelings may also create belonging uncertainty (doubts in their
mind about the quality of their social bond and relationships in these situations.)
When a minority student does poorly on a test, he or she must confront a disturbing possibility:
that others will attribute the failure to racial inferiority. Females face the same problem when
they venture into academic domains where stereotypes suggest that they are inferior to males,
such as mathematics, engineering and the physical sciences. That is, they worry about people
blaming their families on their sex.
Researchers have collected data suggesting that the IQ gap between whites and African-
Americans is due to cultural differences in knowledge due to disparities in exposure to
information. Cultural disparities in IQ reflect difference sin knowledge rather than differences in
New Directions in the Assessment and Study of Intelligence:
Factory analysis: correlations among many variables are analyzed to identify closely related
clusters of variables.
Thurstone found that he could carve intelligence in to seven distinct factors called Primary
mental abilities: word fluency, verbal comprehension, spatial ability, perceptual speed, numerical
ability, inductive reasoning, and memory.
Fluid intelligence: involves reasoning ability, memory capacity, and speed of information
Crystallized intelligence: involves ability to apply acquired knowledge and skills in problem
Biological indexes of Intelligence:
Inspection time: asses how long it takes participants to make simple perceptual discrimination
that meet certain criterion of accuracy. Testing perspective: emphasizes measuring the amount of intelligence people have and figuring
out why some have more than others.
Cognitive perspective: focuses on how people use their intelligence. The interest is in the process
rather than amount.
Robert Sternberg‟s triarchic theory of human intelligence: consists of three parts –
contextual subtheory: intelligence is a culturally defined concept.
Experiential subtheory: he explores the relationship between experience and intelligence. He
emphasizes to factors as the hallmarks of intelligence behaviour. The first is the ability to deal
effective with novelty-new tasks, demands, and situations. The second factors the ability to learn
how to handle familiar tasks automatically and effortlessly.
componential subtheory: describes three types of mental processes that intelligence thought
depends on: metacomponents, performance components and knowledge-acquisition components.
Analytical intelligence: involves abstract reasoning, evaluation, and judgment (crucial to most
Creative intelligence: involves the ability to generate new ideas and to be inventive in dealing
with novel problems.
Practical intelligence: involves the ability to deal effectively with the kinds of problems that
people encounter in everyday life, such as on the job or at home.
Some argue that the term intelligence is so broad, encompassing virtually any valued human
ability, that it makes the term almost meaningless.
Emotional intelligence: consists of the ability to perceive and express emotion, assimilate
emotion in thought, understand and reason with emotion and regulate emotion. It can enhance
the prediction of success at school, at work, and in interpersonal relationships.
Creativity: involves the generation of ideas that are original, novel, and useful.
Divergent thinking: (thinking that goes off in different directions). One tries to expand the range
of alternatives by generating man possible solutions.
Convergent thinking: one tries to na