Psyc 101

The Study of Intelligence

Francis Galton

First scientific theory & measurement of intelligence

Francis Galton

• Founder of EUGENICS movement (1883)

• Theory: Intelligence =

Strength of Nervous System

• Tests: Battery of psycho-physical reactions

• Stats:With C. Pearson developed correlation coefficient

r = -1 to 0 to +1

Galton’s battery of tests

• Hand squeeze strength• Pain threshold• Reaction time• Breathing capacity• Head size• Judgment of 10 seconds• Memory tasks• etc.

Galton’s Laboratory

Galton’s form for recording psycho-physical test results

James Cattell

Galton’s protégéat Columbia

Found (with Wissler) psycho-physical tests did not correlate highly

Alfred Binet

Alfred Binet

• Tried THEORY BASED test construction (like Galton)

• Sub-tests:memory suggestability

imagination aesthetic sentiment

imagery moral sentiment

attention muscular strength

comprehension motor ability

Alfred Binet

• Sub-tests failed to inter-correlate

• Concluded intelligence complex & multiple

• At gov’t request, created test for schools

• Turned to PREDICTION-BASED strategy for constructing a test of intelligence

Binet testing a child

Theodore Simon

Binet’s collaborator

Sample items from Binet’s test

Binet Test

Mental Age= 1 year for each “year” test passed

+ 1/5 year for each older sub-test passed

85% within 1 year of chron. age = “normal”

7% mental age 2+ years behind chron. age

& failing school = “subnormal”

Binet testPredicted school performance,

up to age 15 or 16

Identified:

– morons “mildy retarded”

– imbeciles “moderately retarded”

– idiots “profoundly retarded”

William Stern

Intelligence Quotient =

Mental Age ÷ Chronological Age

( Terman later multiplied by 100 & redesigned test to yield “bell curve” distribution without calculation of “mental age.” )

Henry Goddard

translated Binet test

Eugenics advocate

Ellis Island testing

book on “Kallikaks”

Goddard and “Feeble-Minded Club”

Testing Immigrants at Ellis Island

Henry Goddard

“Our thesis is that the chief determiner of human conduct is a unitary mental process which we call intelligence; [that] the intellectual or mental level for each individual is determined by the kind of chromosomes that come together with the union of the germ cells; that it is but little affected by any later influences…”

Henry Goddard

“The people who are doing the drudgery are, as a rule, in their proper places.”

Henry Goddard

“We must learn that there are great

groups of men, laborers, who are but little

above the child, who must be told what to

do and shown how to do it; and who, if we

would avoid disaster, must not be put into

positions where they will have to act upon

their own initiative or their own judgment.”

Henry Goddard

“Now the fact is, that workmen may have a 10 year intelligence while you have a 20. To demand for him such a home as you enjoy is as absurd as it would be to insist that every laborer should receive a graduate fellowship. How can there be such a thing as social equality with this wide range of mental capacity?”

Henry Goddard

“Democracy means that the people

rule by selecting the wisest, most

intelligent and most human to tell them

what to do to be happy. Thus Democracy

is a method for arriving at a truly

benevolent aristocracy.”

The Kallikak Family:A Study in Feeble-Mindedness

Henry Goddard

1912

Deborah Kallikak at the Training School

Normal & “Degenerate” Descent Lines

“There can be no doubt that the photographs of the Kallikak family members have been retouched… this retouching was limited to the facial features – specifically eyes, eyebrows, mouths, nose and hair.”

-- Smithsonian AnalysisDirector of Photographic Services, Smithsonian Inst.

“The harshness clearly gives the appearance of dark, staring features, sometimes evilness, and sometimes mental retardation. It would be difficult to understand why any of this retouching was done were it not to give the viewer a false impression of the characteristics of those depicted.”

-- Smithsonian Analysis

Lewis TermanCreated Stanford-Binet

Changed scoring: mental / chron X 100; 100 = average for age

Began “Terman Study”

Eugenics advocate

Lewis Terman

“Defectives” should be segregated, which “will ultimately result in curtailing the reproduction of feeble-mindedness and in the elimination of an enormous amount of crime, pauperism, and industrial inefficiency.”

Lewis Terman

“Not all criminals are feeble-minded, but all feeble-minded persons are at least potential criminals. That every feeble-minded woman is a potential prostitute would hardly be disputed by anyone.”

Lewis Terman

“Moral judgment, like business judgment, social judgment, or any other kind of higher thought process, is a function of intelligence. Morality cannot flower and fruit if intelligence remains infantile.”

Lewis Terman

“The common opinion that the child from a cultured home does better in tests solely by reason of his superior home advantages is an entirely gratuitous assumption… The children of successful and cultured parents test higher than children from wretched and ignorant homes for the simple reason that their heredity is better.”

Lewis Terman

Women tested to have IQs equal to men, but he opposed allowing them access to professions:

Women with IQs between 100 and 120 should get jobs as teachers or “high-grade stenographers” and paid at level of men with IQs of 85.

Lewis Terman

“Among laboring men and servant girls there are thousands like them [borderline feebleminded, with IQs = 70 – 80]… The tests have told the truth… No amount of school instruction will ever make them intelligent voters or capable citizens…

Lewis Terman

“They represent the level of intelligence which is very common among Spanish-Indian and Mexican families of the Southwest and also among Negroes….

Their dullness seems to be racial, or at least inherent in the family stocks from which they came… ”

Lewis Terman

“There is no possibility at present of convincing society that they should not be allowed to reproduce, although from a eugenic point of view they constitute a grave problem because of their unusually prolific breeding.”

Robert Yerkes

Pioneer primate researcher

APA President

Head of WWI IQ testing committee

Eugenics advocate

Army Alpha

sample questions

Army Alpha

sample problems

Army Alpha Items

• Washington is to Adams as first is to…

• Crisco is a: patent medicine, disinfectant, toothpaste, food product

• The number of a Kaffir’s legs is: 2, 4, 6, 8

• Christy Mathewson is famous as a: writer, artist, baseball player, comedian

Army Beta

sample problems

Army IQ Testing Major Findings

• Average mental age of white American adult men: 13

• 37% of white American adult men are “morons”

Army Alpha results by race

Army beta results by race

A Study of American Intelligence

Carl C. Brigham

1923

A Study of American IntelligenceRobert Yerkes 1923

Army tests free of cultural bias:

“These group examinations were originally intended, and are now definitely known, to measure native intellectual ability.”

A Study of American IntelligenceRobert Yerkes

“All officers without exception agree that the Negro lacks initiative, displays little or no leadership, and cannot accept responsibility… All officers seem further to agree that the Negro is a cheerful, willing soldier, naturally subservient. These qualities make for immediate obedience, although not necessarily for good discipline, since petty thieving and venereal disease are commoner than with white troops.”

A Study of American IntelligenceRobert Yerkes

“The author presents not theories or opinion but facts. It behooves us to consider their reliability and their meaning, for no one of us as a citizen can afford to ignore the menace of race deterioration or the evident relations of immigration to national progress and welfare.”

A Study of American IntelligenceC. C. Brigham

“We have here an investigation which, of course, surpasses in reliability all preceding investigation, assembled and correlated a hundred-fold. These army data… give us a scientific basis for our conclusions.”

Study of American Intelligence

• Northern blacks higher IQs than Southern

– Not due to less racism or better environment

– Northern blacks had “greater admixture of white blood”

– North lured more intelligent blacks from South

Study of American Intelligence

• Nordics (“a race of soldiers, sailors, adventurers, and explorers, but above all of rulers, organizers, and aristocrats) scored higher than Alpines (“submissive to authority, the perfect slave, the ideal serf, the model subject” and Mediterraneans because of race

A Study of American IntelligenceC. C. Brigham

“Running parallel with the movements of these European peoples, we have the most sinister development in the history of this continent, the importation of the Negro… The decline of American intelligence will be more rapid than the decline of the intelligence of European national groups, owing to the presence here of the Negro. These are the plain, ugly facts that our study shows.”

A Study of American IntelligenceHenry Osborne

“I believe those tests were worth what the war cost, even in human life, if they served to show clearly to our people the lack of intelligence in our country, and the degrees of intelligence in different races who are coming to us, in a way which no one can say is the result of prejudice…”

A Study of American Intelligence

Calvin Coolidge:

“Biological laws show… that Nordics deteriorate when mixed with other races.”

Boston Globe editorial:

“Danger that World Scum will Demoralize America.”

Brigham called for…

“selective breeding [to create] a world in which all men will equal the top ten percent of present men.”

1922 Walter Lipman

Wrote series of 10 articles in the New Republic attacking spreading use of IQ tests, which he warned was creating “an intellectual caste system in which the task of education had given way to the doctrine of predestination and infant damnation.”

1930s: Brigham Recants

“Most psychologists working in the test field have been guilty of a naming fallacy which easily enables them to slide mysteriously from the score in the test to the hypothetical faculty suggested by the name given to the test.”

Brigham recants (con’t)

“The study with its entire hypothetical superstructure of racial differences collapses.”

“Comparative studies of various national and racial groups may not be made with existing tests… One of the most pretentious of these comparative racial studies – the writer’s own – was without foundation.”

Charles Spearman

Believed IQ inherited

Eugenics advocate

Created factor analysis: Showed intercorrelation among Binet’s sub-tests

Two-factor theory: g + s-s

Lewis Thurstone

Invented factor rotation technique

Found 7 factors – “Primary Mental Abilities”

Primary Mental Abilities

• Verbal Comprehension

• Word fluency

• Number facility

• Spatial visualization

• Memory

• Perceptual speed

• Reasoning

David Wechsler

Developed W.A.I.S. (Wechsler Adult Intelligence Scale)

W. A. I. S.

W. A. I. S.