Assessing Intelligence

RG 11b

Assessing Intelligence

Psychologists define intelligence testing as a method for assessing an individual’s mental

aptitudes and comparing them with others using numerical scores.

Alfred Binet

Alfred Binet and his colleague Théodore

Simon developed the first standardized intelligence

test…they were commissioned by the French government to

design a “test” to identify French children who

would have problems in regular classes

Binet

Set out to find a child’s mental age, or the average age of individuals who achieve a particular level of

performance

Binet did not create the test to LABEL children…he actually warned that if the information were misused it would do just this…instead he wanted only to find a way to help improve the educational experience

of French children

Lewis Terman

Lewis Terman, in the US, adapted/revised

Binet’s test for American school children and named the test the

Stanford-Binet IQ Test. (he worked at Stanford)

A form of the Stanford-Binet is still in use

today…

Stanford-Binet

Today…the Stanford-Binet is given orally and varies in nature according to the person taking the test● Children – given figures to copy or everyday problems to solve● Adults – asked to solve analogies, explain proverbs and describe similarities that underlie sets of words

The examiner begins by finding a mental age at which person can answer all questions…move on to more difficult problems…when mental age is reached at which no items can be answered, test is over

William SternThe formula of

Intelligence Quotient (IQ) introduced by William

Stern is:

Example…

IQ is no longer computed this way…

David Wechsler

Wechsler developed the Wechsler Adult

Intelligence Scale (WAIS) and later the Wechsler Intelligence Scale for Children (WISC), an intelligence test for

preschoolers – they are the most widely used IQ

tests today.

WAIS

WAIS measures overall intelligence – consists of 2 parts, verbal and performance

Verbal – vocab definitions and comprehension

Performance – timed assembly of small objects and arranged pictures in logical order

Normally verbal and performance are within close range, yet separate scores can give a more precise picture of a person’s specific abilities

WAIS example

Aptitude and Achievement Tests

Achievement tests are intended to reflect what you have already learned – current level of knowledge

Examples??

Aptitude tests are intended to predict your ability to learn a new skill – how well you could do

Examples???

What is your opinion of aptitude tests? Do they prove what they say they are measuring?

D. Flynn

●While Thurstone, Gardner, Sternberg, and Goleman all tried to define intelligence, Flynn is know for his observation that intelligence, as measured by IQ tests, is increasing.●What theories does each theorist argue?●What about Spearman?

Principles of Test Construction

For a psychological test to be acceptable it must fulfill three criteria:

●Standardization

●Reliability●Validity

StandardizationStandardization = test items piloted on a similar

population of people and “norms” have been established

Norms are developed by calculating the average score achieved by a particular group and then each person’s score can be compared to see how it differs from people who have taken the test in the past

● EX: AP test given to college freshman as a final exam to set norms (known as the standardization sample). periodically tests are re-standardized – given to a random, representative sample to reset/check the established norms (including intelligence tests whose “normal” score is 100).

Normal Curve

Standardized tests establish a normal distribution of scores on a tested population — a bell-shaped

pattern called the normal curve.

Flynn Effect

In the past 60 years intelligence scores have steadily risen by an average of 27 points — a

phenomenon known as the Flynn effect.

Why do you think this has happened????

Reliability

A test is reliable when it yields consistent results.

To establish reliability researchers establish different procedures:

●Split-half Reliability: Dividing the test into two equal halves and assessing how consistent the scores are.

●Reliability using different tests: Using different forms of the test to measure consistency between them.

●Test-Retest Reliability: Using the same test on two occasions to measure consistency.

Validity

Reliability of a test does not insure validity.

Validity of a test refers to what the test is supposed to measure or predict.

●Content Validity: Refers to the extent a test measures a particular behavior or trait.

●Predictive Validity: Refers to the function of a test in predicting a particular behavior or trait.

Reliability of a test does not insure validity...in other words, a test can be consistent without testing what it is

supposed to test!

Is intelligence fixed or does it change over time?

It depends on the type of intelligence…

●Fluid intelligence – reflects information-processing capabilities, reasoning and memory

● tends to decline as we age●Crystallized intelligence -- accumulated

knowledge, skills and strategies that have been learned through experience

● tends to increase throughout life

So… a 70-year-old may have more crystallized intelligence thana 30-year-old, but his processing will definitely be slower,

which could make it look like he has less intelligence.