Chapter 9: Psychology
Intelligence and Psychological Testing
Key Concepts in Psychological Testing
Psychological test: is a standardized measure of a sample of a person’s behaviour.
Psychological tests are measurement instruments; they are used to measure the
individual differences that exist among people in abilities, aptitudes, interests, and
aspects of personality.
Mental Ability Tests:
Intelligence tests: measure general mental ability; intended to assess intellectual
potential rather than previous learning or accumulated knowledge.
Aptitude tests: assess specific types of mental abilities. (Differential aptitude
tests: assess verbal reasoning, numerical ability, abstract reasoning. Achievement
tests: measure previous learning instead of potential.)
Achievement tests: gauge a person’s mastery and knowledge of various subjects.
Personality tests: measure various aspects of personality, including motives,
interests, values, and attitudes.
Standardization and Norms:
Standardization: refers to the uniform procedures used in the administration and
scoring of a test.
Test Norms: provide information about where a score on a psychological test
ranks in relation to other scores on that test.
A percentile score: indicates the percentage of people who score at or below the
score one has obtained. (Ex. 82 percentile means that you appear to be as
assertive or more assertive than 82% of the sample of people who provided the
basis for the test norms.)
Refers to the measurement consistency of a test (or of other kinds of measurement
Approach to check test retest reliability: estimated by comparing subject’s scores
on two administrations of a test.
A correlation coefficient: is a numerical index of the degree of relationship
between two variables.
The closer to +1.00, the more reliable the test.
Refers to the ability of a test to measure what it was designed to measure.
Content validity: refers to the degree to which the content of a test is
representative of the domain it’s supposed to cover. (Crucial on classroom tests) Criterionrelated validity: is estimated by correlating subjects’ scores on a test
with their scores on an independent criterion (another measure) of the trait
assessed by the test. (Used to predict performance in university, job capability,
Construct validity: the extent to which there is evidence that a test measures a
particular hypothetical construct.
The Evolution of Intelligence Testing
Mental age: indicated that he or she displayed the mental ability typical of a child
of that chronological (actual) age.
Terman and the StanfordBinet:
Intelligence Quotient: is a child’s mental age divided by chronological age,
multiplied by 100.
The debate about the structure of intelligence
Factor analysis: correlations among many variables are analyzed to identify
closely related clusters of variables.
G stands for general mental ability, which is an important core factor that all
cognitive abilities share.
Thurstone carved intelligence into seven independent 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
Crystallized intelligence: involves the ability to apply acquired knowledge and
skills in problem solving.
Contemporary IQ tests subdivide g into 1015 specific abilities.
Basic Question about Intelligence Testing
What do modern IQ scores mean?
Normal distribution: is a symmetric, bellshaped curve that represents the pattern
in which man characteristics are dispersed in the population.
Deviation IQ scores: that locate subjects precisely within the normal distribution,
using the standard deviation as the unit of measurement.
Standard deviation shows where you fall in the normal distribution of intelligence,
100 being the average.
Do intelligence tests have adequate reliability? Yes.
They also have good validity and measure what they are supposed too
The main idea is to predict school performance
IQ scores as predictors of performance within a particular occupation:
1) There is a substantial correlation between IQ scores and job performance
2) Correlation varies depending on the complexity of a job’s requirements
3) This association holds up even when workers have more experience at their jobs
4) Measures of specific mental abilities and personality traits are much less
predictive of job performance than measures of intelligence.
Extremes of Intelligence
Refers to subnormal general mental ability accompanied by deficiencies in
adaptive skills, originating before age 18.
Three broad domains of adaptive skills:
1) Conceptual skills: managing money, and writing a letter
2) Social skills: making friends, and coping with others’ demands
3) Practical skills: preparing meals, using transportation, shopping
Levels of Intellectual Disability:
Firs level mild: IQ range 5170, education possible grade 6, and be self
Second level is moderate: IQ 3650, grade possible 24, can be semiindependent.
Third level Severe: IQ 2035: limited speech, toilet habits, and needs total
supervision and can help to contribute to support
Fourth level Profound: IQ below 20, little or no speech; not toilet trained, and
needs total care.
Origins of Disabilities:
Down syndrome slanted eyes, stubby limbs, and thin hair, may carry an extra
Fragile x syndrome: common cause of hereditary intellectual disability, there is a
mutation in the inherited gene.
Phenylketonuria: is a metabolic disorder to an inherited enzyme deficiency, which
can lead to intellectual disability.
Hydrocephaly: Excessive accumulation of cerebrospina