Chapter 9:Intelligence and Psychological Testing
Key Concepts in Psychological Testing
Psychological test is a standardized measure of a sample of a person’s behaviour.
• they are used to measure individual diﬀerences that exist among people in abilities,aptitudes,and aspects of
• your responses of psychological test represent a sample of your behaviour.
• a particular behaviour sample may not be representative of our characteristic behaviour.
1. Principal Types of Tests:
a) Mental ability tests:
• they try to measure general mental ability
• they are the most common psych tests today
• there are 3 types of principal subcategories:
Type of Mental Ability What does it measure?
Intelligence - measures general mental ability
- assesses intellectual potential
Aptitude - assesses speciﬁc types of mental abilities
- measures potential more than knowledge, but
break mental ability into separate components
Achievement - measures a person’s mastery and knowledge of
- has a speciﬁc focus,but it measures previous
learning instead of potential.
b) Personality tests:
Personality tests measure diﬀerent aspects of personality,including motives,interests,values,and attitudes.
• questions do not have a right or wrong answers
2. Standardization and Norms: • both personality scales and tests of mental abilities are standardized measures of behaviour.
Standardization refers to the uniform procedures used in the administration and scoring of a test.
• all subjects get the same instructions,the same questions,and the same time limits so that their scores can be
Tests norms provide information about where a score on a psychological test ranks in relationship with other
scores that test.
• psych tests 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 obtained.
• a standardization group is a sample group of people that the norms are based on
• consistency in measurement is essential to accuracy in measurement.
Reliability refers to the measurement consistency of a test.
• a test’s reliability can be estimated in several ways:
- one approach is to check test-retest reliability, which is estimated by comparing subjects’ scores on 2
administrations of a test(ex. ask subject to come and do the test on 2 occasions).
Correlation coeﬃcient is a numerical index of the degree of relationship between 2 variables.
• in test-retest reliability, the 2 variables that must be correlated are the 2 sets of scores from the 2
administrations of the test.
• if people get similar scores on the 2 administrational tests,this would be considered as a positive correlation.
there are no absolute guidelines about acceptable levels of reliability.
• the higher the reliability coeﬃcient,the more consistent the test is.
Validity refers to the ability of a test to measure what it ways designed to measure
it also refers to the accuracy or usefulness of the inferences or decisions based on a test.
• there are 3 types of validity:
Type of Validity Deﬁnition Example
Content Validity - the degree to which the content of a tes- achievement and educational tests
representative of the domain it’s supposed to
- it’s evaluated with logic more than with
statistics Type of Validity Deﬁnition Example
Criterion-Related Validity - it’s estimated by correlating subject’s sco- tests that are used to make predictions
a test with their scores on an independent about speciﬁc aspects of individual’s
criterion(another measure) of the trait assessbehaviour.
by the test - used to predict performance in
university, job capability,etc.
Construct Validity - the extent to which there is evidence that - used to measure abstract personal
test measures a particular hypothetical qualities(ex. creativity, intelligence,etc.)
construct - no obvious criterion measures exist for
these abstract qualities, which are called
hypothetical constructs .
- the process requires a series of studies
that examine the correlations between
the test and various measures related to
the trait in question.
The Evolution of Intelligence Testing
1. Galton’s Studies of Hereditary Genius:
• Galton was the ﬁrst one to try to measure intelligence
• he tried to asses mental ability by measuring simple sensory processes because he belived that bright people
should exhibit exceptional sensory acuity.
3. Binet’s Breakthrough:
• the Binet-Simon scale expressed a child’s score in terms of “mental age.”
Mental age indicates that a child displays the mental ability typical of a child of that chronological age.
• he constructed this test in order to see which children needed special training.
4. Terman and the Stanford-Binet:
Terman created the Stanford-Binet Intelligence scale
• the scale was similar to Binet’s scale,but it added a new scoring scheme based on IQ
An intelligence quotient(IQ) is a child’s mental age divided by chronological age, multiplied by a 100.
• IQ= MA/CA x 100 • the ratio of mental age to chronological age made it possible to compare children of diﬀerent ages.
5. Wechsler’s Innovations:
• he wanted to improve the measurement of intelligence in adults.
• the Wechsler scales were characterized by at lease 2 major innovations:
1) He made his scales less dependent on subject’s verbal ability than the Stanford-Binet
- he included many items that required nonverbal reasoning
- he formalized the computation of separate scores for verbal IQ,performance(nonverbal) IQ,and full-
2) He discarded the IQ in favour of a new scoring scheme based on the normal distribution.
6. Intelligence Testing Today:
• today IQ tests fall into 2 categories:
1) Individual IQ tests:
- administered only by psychologists who have special training for this purpose.
- psychologist works face to face with a single examinee at a time
- Ex. Stanford-Binet and Wechsler scales
2) Group IQ tests:
- can be administered to large groups of people at once
- they are inexpensive
- used at all educational levels
- Ex. Otis-Lennon School Ability Test and Cognitive Abilities Test
Basic Questions about Intelligence Testing
1. What Kinds of Questions Are on Intelligence Tests?
• questions vary from test to test
• variations depend on whether the test is designed for children or adults (or both) and whether the test is
designed for groups or individuals.
• Check Fig. 9.6 on pg. 379 2. What Do Modern IQ Scores Mean?
The normal distribution is a symmetric,bell-shaped curve that represents the pattern in which many
characteristics are dispersed in the population.
• when a trait is normally distributed,most cases fall near the centre of the distribution(an average score) and
the number of cases gradually declines as one moves away from the centre in either direction.
Deviation IQ scores locate subjects precisely within the normal distribution, using the standard deviation as
the unit of measurement.
• for most IQ tests,the mean of the distribution is set at 100 and the standard deviation is set at 15.
• a score of 85 shows that a person scored one standard deviation(SD) below the mean
3. Do Intelligence Tests Measure Potential or Knowledge?
• intelligence tests are intended to measure intellectual potential
• they do so by presenting novel questions that require test takers to think on their feet, rather than questions
that simple tap factual knowledge
• IQ tests measure a blend of potential and knowledge
4. Do Intelligence Tests Have Adequate Reliability?
• IQ test produce consistent results when people are retested.
• speciﬁc testing may yield an unrepresentative score
the most common problem is that low motivation or high anxiety may drag a person’s score down on a
5. Do Intelligence Tests Have Adequate Validity?
• intelligence test do measure what they are supposed to measure
• IQ tests are valid measures of the kind of intelligence that’s necessary to do well in academic work, but if the
purpose is to assess intelligence in a broader sense,the validity of IQ tests is questionable.
• IQ tests do not tap social competence, practical problem solving, creativity, or artistic talent.
• there are 3 categories of intelligent behaviour: Type of Intelligence Deﬁnition
Verbal - speaks clearly and articulately
- is verbally ﬂuent
- is knowledgable about a particular ﬁeld
- read with high comprehension
Practical - sees all aspects of a problem
- sizes up situations well
- makes good decisions
- poses problem in an optimal way
Social - accepts others for what they are
- has social conscience
- thinks before speaking and doing
- is sensitive to other people’s needs and desires
• IQ tests focus narrowly on academic/verbal intelligence
6. Do Intelligence Tests Predict Vocational Success?
• people who score high on IQ tests are more likely than those who score low to end up in high-status jobs.
• intelligence fosters vocational success,but the strength of the relationship is modest
7. Are IQ Tests Widely Used in Other Cultures?
• in most non-Western cultures IQ tests are not widely used, because Western IQ tests do not translate well
into the language and cognitive frameworks of many non-Western cultures.
• diﬀerent cultures have diﬀerent conceptions of what intelligence is and value diﬀerent mental skills.
Extremes of Intelligence
1. Mental Retardation/Intellectual Disability:
Intellectual Disability(mental retardation) refers to subnormal general mental ability accompanied by
deﬁciencies in adaptive skills, originating before age 18.
• adaptive skills consist of everyday living skills in 10 domains, such as communication(writing a letter), self-care
(dressing oneself), home living(preparing meals), social interactions(coping with other’s demands),