-History of Intelligence Testing

Galton

Believed that intelligence was largely a matter of superior perceptual (ability to detect subtle differences in pitch) & physical attributes (reaction time).

Believed that intelligence was inherited with some families showing clear biological superiority over others "Hereditary Genius."

Founded the Eugenics movement, which held that only bright people should mate & produce offspring.

Binet-Simon Scales

Reason for development: Early tests involved arranging mental tasks from easiest to hardest.

Binet found that as children grow older, they were able to answer increasingly difficult items. Moreover, brighter children performed like older children while less capable children performed like younger children.

Mental age: measure of intelligence derived by comparing an individual's score on an intelligence test with the average performance of individuals of the same age.

Stanford-Binet Intelligence Scale

English version of Binet-Simon scale where test items were extended into adulthood, age-level norms were developed by giving test to thousands of children and test administration procedures were standardized.

Intelligence Quotient (IQ)
IQ = Mental Age ÷ Chronological Age × 100

Simulated Stanford-Binet Items: Items Similar to Those on the Stanford-Binet Intelligence Scale (2 YEAR LEVEL)
Children show knowledge of basic vocabulary words by identifying parts of a doll such as the mouth, ears, and hair.
Children show counting and spatial skills along with visual-motor coordination by building a tower of four blocks to match a model.

Wechsler Scales

Verbal & Non-Verbal (VIQ, PIQ, FSIQ)
Subscales
WAIS, WISC, WPPSI
Simulated WAIS Items & Profile

Subtests from the Wechsler Adult Intelligence Scale:

VERBAL SUBTESTS:
Information:"What is the capital of the United States?" "Who was Shakespeare?"
Comprehension: "Why do we have ZIP Codes?" "What does 'A' stitch in time saves 9 mean?"
Arithmetic: "If 3 candy bars cost 25 cents, how much will 18 candy bars cost?"
Similarities: "How are good and bad alike?""How are peanut butter and jelly alike?"
Digit Span: Repeating a series of numbers forwards and backwards.
Vocabulary: "What does canal mean?"

Items for verbal subtests 1, 2, 3, 4, and 6 are similar but not identical, to actual test items on the WAIS.

-Principles of Psychological Tests

Reliability

Reliability Defined: consistency

Types:

Test-Retest:
Definition: The degree to which test scores obtained from subjects at one point in time will agree with test scores obtained from the same group at another point in time.
Example: Intelligence test scores obtained by a group of subjects in January should agree with their scores obtained in July.

Alternate Form:
Definition: The degree to which test scores obtained on one form of a test will agree with scores on an alternate form of the same test.
Example: Intelligence test scores obtained on form L of the Stanford-Binet should agree with test scores obtained on form M.

Split-Half:
Definition: The degree to which test scores obtained on one half of a test will agree with test scores on the other half.
Example: Depression test scores obtained by a group of subjects on the even items should agree with scores on the odd items.
Determining Reliability

Validity

Validity Defined: Does it measure what it claims to measure?

Types:

Concurrent:
Definition: The degree to which test scores relate to scores on other measures taken at the same time.
Example: A test of depression should produce high scores in people diagnosed as depressed.

Predictive:
Definition: The degree to which test scores relate to future perfomance.
Example: People who receive high scores on SATs are expected to achieve high GPA scores in college.

Construct:
Definition: The degree to which a test measures a theoretically derived psychological construct.
Example: A test of depression should correlate with recognized characteristics of depression such as low self-esteem, guilt, & feelings of sadness.

Determining Validity

Standardization

Defined: The development of procedures for:
administering psychological tests and
scoring psychological tests and
the collection of norms that provide a frame of reference for interpreting test scores.

-Extremes of Intelligence

Distribution of IQ Scores

Features of Mental Retardation

Terman Study of Gifted

A Test of the Early Ripe-Early Rot Myth

1500 Children with IQ 135 & up (Follow-up at age 40)

Superior in:
Health
Physique
Athletic
Ability
Achievement

Terman Study: Accomplishments at age 40:
90 Books
375 Plays
2000 Articles
200 Patents

-Misuse of Intelligence Tests

Public Health Service 1912:
Decides to screen immigrants for mental defectiveness and deportation. Goddard claims 87% Russians, 83% Jews, 80% Hungarians & 79% Italians were feebleminded.

WW I Testing:
Testing of recruits which led to assumptions of superiority for northern & western European contries compared to southern & eastern Europe.


-Hereditary & Environmental Determinants of Intelligence

Nurture's Influence

Nature's Influence

Colorado Adoption Project




Conclusions

-Explaining Differences in Intelligence Scores

Proposed Causes:
Test Bias
Evidence Against Test Bias Explanation:

1). Minority Group Students with a given IQ score generally do about as well in school & at school tasks as do European-Americans with the same IQ score.

2). Failure of "reverse bias" tests (BITCH) to predict performance in school or on the job.

"If the aborigine drafted an IQ test, all of Western civilization would presumably flunk it."
~ Stanley Garn

"That's true... & while the test would probably predict how well someone would survive in the Australian outback, the test scores would have no relationship with academic functioning i.e., the scores would tell us nothing about how well Johnny will do in school." ~ William Gayton

3). Failure to support the hypotheses that "race of tester" or "language confusion" led to lowered scores.

Innate Differences Due to Heredity

Jensen Monograph .80
Kamin Argument



CONCLUSION: A trait may have strong genetic component, but group differences do not prove innate differences between the groups.


DIfferent Life Experiences

Introduction to Mental Retardation
http://thearc.org/faqs/mrqa.html