birthof i qtest

The Birth of IQ Testing

From Binet to the Army Alpha

Physical Differences

• Early attempts to understand intelligence utilized unrefined examinations of group differences among people’s physical structure. Investigators primarily examined these areas by studying group averages for skull capacity or actual brain size.

Phrenology

Body Morphology

Louis Agassiz

• “There are upon earth different races of men, inhabiting different parts of its surface, which have different physical characters; and this fact…presses upon us the obligation to settle the relative rank among these races, the relative value of the characters peculiar to each, in a scientific point of view… As philosophers it is our duty to look it in the face.” (1850)

Samuel George Morton (1799 -1851)

Samuel George Morton

• Morton (1799 -1851) was Philadelphia physician who collected and examined1,849 skulls of Americans. Most of these skulls came from the various Native American tribes that had once inhabited the land. Morton believed that a ranking of the races could be established objectively by looking at the cranial capacity of the skulls. He used his detailed research on cranial capacity to support his theory of intellectual superiority of different racial groups.

Morton’s Measurements

• Morton cared about accuracy.

• Started by using mustard seed.

• Changed to using lead pellets because they were more exact.

• Still got it wrong.

Samuel George Morton

• Stephen Jay Gould (1981) criticized his work with four general problems:– (1) He chose to include/delete sub-samples of skulls form his

calculations based on how they fit his theory;

– (2) He measured skull capacity with seeds which is inaccurate and subject to bias; re-measurements with more precise tools indicated that Caucasians were typically over-estimated and other groups were underestimated;

– (3) He assumed that cranial size indicated intelligence and didn’t considered the impact of one physical stature or gender on the skull size;

– (4) He miscalculated rounding estimates that consistently favored his hypothesis.

Dr. Paul Broca (1824-1880)


• Broca was a chief of surgery at a major Parisian hospital who was interested in the variations found among people’s skeletal structures, particularly their skulls. He developed several instruments for measuring these variations.


• Dr. Broca’s examination of brain size was influenced by his desire to demonstrate physical evidence for his belief that Caucasian males were intellectually superior to women and men of other races.

For example:

• When Broca found that criminals mean brain size was larger than honest people’s average brain size, he dismissed this information stating that the executions caused the brain structure to change or that the mean age at death was younger.

More Examples

• When Gratiolet (an opponent of the belief that brain size was correlated with intelligence) indicated that French brains were smaller than German brains, Broca correctly adjusted the German brain sizes to account for differences in body stature.

• However, he did not use this type of adjustment when he examined the differences between men and women’s brain sizes.

James Cattell

• The term mental test appeared for the first time in a paper by James McKeen Cattell (1890).

• Called for standardized tests of intelligence and proposed measurements of intelligence: – Dynamometer pressure – Rate of movement – Two-point skin sensitivity threshold – Amount of pressure to the forehead needed to

cause pain

Measures of Intelligence

• Just noticeable differences in judging weights • Reaction time for sound • Time for naming colors • Bisection of a 50 cm line • Judgment of a 10-second time period• Number of letters remembered after a single

presentation

Alfred Binet

• First IQ tests developed by Alfred Binet in France.

• These were developed to identify children who needed ‘special’ education

• Binet believed that IQ could be increased by education

1903:

• French gov’t needed differentiate those who could benefit from normal education from those who would not (stupid vs. malicious) – “...[some] children, if considered educably

retarded, should be grouped in special classes annexed to the regular school, or in a special establishment, and...that a special class for the educable be opened for the present in one of the Paris schools, as a demonstration.”

1905:

• Scale First practical test of intelligence• Developed by Binet and Theodore Simon • A test that differentiated between normal

children and those who required additional instructional resources

• Had 30 tests items ordered in level of difficulty

• The more tasks completed, the greater the assumed intelligence of the subject

Binet Scale

• Used the following types of tests: – Association tests in which the child was

given 25-30 words and asked to describe the idea each word aroused

– Sentence completion – Picture drawings – Object drawing and description – Digit repetition and other memory and

attention tests

1908 Revision

• Test items are now grouped by ages at which children usually passed them Rather than by level of difficulty

• If a majority of children at a given age (75- 90%) passed an item, it was assigned to that age level

• 54 tests 14 of the original 30 Created different test for children of different ages

Mental Age

• When a child was tested, his or her mental level was said to be equivalent to that of the highest age group wherein he or she could pass all of the tests for that group

Deriving the IQ

• calculated as• IQ = Mental Age Chronological age x 100

Nowadays NORM referenced.. that is the average performance of a group is calculated, then individual comparison

IQ Scale

1. 140 and more very high

2. 120 – 139 high

3. 110 – 119 above average (college and university students)

4. 90 – 109 average

5. 80 – 89 sub average

6. 70 - 79 the border between normality and deteriorate mental capacity

7. 50 - 69 debility

8. 20 - 49 imbecility

9. less than 20 idiocy

Binet’s Views on Heritability

• Scientific atmosphere dominated by Darwinism and the theory of evolution

• Binet, however, felt that intelligence was modifiable.

• He proposed mental orthopedics • Reaction to the idea that intelligence is

fixed and inherited: “...we must protest and react against this brutal pessimism…”

IQ testing in the USA

• In the USA strong supporters of IQ testing were scientists who believed that IQ is MAINLY hereditary, and that society should breed a superior group of people

Henry Herbert Goddard(1866-1957)

Henry Herbert Goddard

• Encountered and tried out the 1908 Binet scale

• Liked it a lot Developed translation of the scale

• Worked to popularize the scale • Wanted to use adaptations of the Binet

scale to differentiate classes of mental retardation and facilitate treatment

Henry Herbert Goddard

• “It remains now for someone to determine the nature of feeble-mindedness and complete the theory of the intelligence quotient.”

• “If both parents are feeble-minded all the children will be feeble-minded. It is obvious that such matings should not be allowed. It is perfectly clear that no feeble-minded person should ever be allowed to marry or to become a parent.It is obvious that if this rule is to be carried out the intelligent part of society must enforce it.” (1914, p. 561).

Lewis Terman (1877-1956)

Lewis Terman • Terman was the first to argue persuasively for

the utility of the Binet-Simon tests in uncovering superior intelligence.

• Terman adapted the Binet-Simon scales for Americans in 1916.

• The revised scale has since been known as the Stanford-Binet Intelligence Tests, and continues to be in use today.

Lewis Terman

• “If we would preserve our state for a class of people worthy to possess it, we must, as far as possible, prevent the propagation of mental degenerates.”

The Army Intelligence Tests

• The place - The USA• The time - the outbreak of the

great war - (World War 1: 1914 - 1918)

• Robert Yerkes - psychologist• persuaded the US military to

administer IQ tests to 1.75 million army recruits


• Three types of tests

• The Army Alpha - a written test taken by literate recruits

• Eight parts - fill in the missing number - unscramble a sentence, etc

• Some examples– Washington is to Adams as first is to -------– Crisco is a: medicine, disinfectant, toothpaste, food product


• The Army Beta - a pictorial test• for the illiterate or those who failed the Alpha

• this test had 7 parts -• including ‘picture completion tasks

Examples of Wechsler items:


• The third test was a spoken test

• Supposed to be administered to those who failed the Alpha and the Beta


• YERKES said that:

• These tests measure NATIVE INTELLECTUAL ABILITY

• In other words: intelligence which was unaffected by culture or educational opportunities


• Gould reports many problems in the administration of the tests

• Illiterate men were allocated to the Alpha• The queues for the Beta became so long

that some men were reallocated to the Alpha

• Many who failed the Alpha were never recalled


• The BETA test still required men to use pencils and paper - and many had never been educated at all

• Gould suggests that all the results should be viewed with scepticism


• However, the results were used by the army and had great impact - mental testing became….‘scientifically established’

• By 1921 commercial and educational establishments were using the tests

More Problems

• Question as to whether Alpha and Beta actually assessed native ability rather than school learning

• Assessment of school learning could (and probably does) account for racial differences

• Alpha and Beta were highly correlated with school learning

• Yerkes et al. took this to mean that native intelligence kept people in school longer rather than the other way around

The creation of 3 ‘so called facts’

‘Fact 1’

• The average mental age of white American adults stood at 13 … this is just above the level of moronity


‘Fact 2’

• It was possible to grade European immigrants by their country of origin

• The fair people of Northern & Western Europe higher than the Slavs of Eastern Europe who were higher than dark people of southern Europe


‘Fact 3’

• Black people scored lowest of all

• These ‘facts’ were used to provide a genetic explanation for the differences

S J Gould - A Nation of Morons

• Carl Brigham (Yerkes colleague)• Explained the differences in terms of

racial superiority

“we notice the Einsteins of the world BECAUSE they are exceptional for their Jewish race”


• However this argument is opposed by 2 arguments

FIRST• Immigration from different parts of Europe

took place at different times• The most recent immigrants scored worse on

the written tests • If native IQ was being measured, writing skill

should have NO effect


SECOND

• Test scores rose with length of stay in the USA evidencing a cultural bias

• Those who had been in the USA longer were more familiar with American customs & products


• Brigham argued that it was a sign of intelligence to emigrate to the USA and that the brightest came sooner!!

• Later immigrants were progressively more stupid


• Despite the evidence IQ tests took hold

• 1924 US Congress passed the Immigration Restriction Act

• The Act set quotas for immigration to the US based on figures 30 years earlier when immigration from Southern & Eastern Europe was low


• Gould called this -

• A victory for scientific racism• During the next 20 years conditions

in eastern Europe worsened for Slavs and Jews

• The Nazi years


• Gould estimates that

• Immigration quotas barred up to 6 million people from entering the USA


• There is STILL

• No clear operational definition of intelligence

• Both race and IQ are political rather than biological facts

• (Socially constructed)

False Assumptions

• Reification - “Intelligence” actually represents a complex, multifaceted set of human aptitudes, yet it is typically treated as a unitary entity.

• Ranking - Our propensity to place arbitrary order to complex variations.

• Reification & Ranking are both manifested in our societies effort to represent intelligence with one number such that the numbers can be used to rank people’s worthiness.

IQ Changes

– Worldwide improvement in IQ scores

• 3pts. per decade

• Hard to account for this change genetically

Mind as Swiss Army Knife

• The human mind is the Swiss Army Knife that has all the tools.

• Different species have different sets of tools.

Gardner’s Theory of Multiple Intelligence

• Intelligence is defined as the ability to solve problems in a given situation

• Types – Linguistic – Muscial – Logical/Mathematical – Spatial – Bodily/Kinesthetic

–Intrapersonal –Nature –Spiritual –Existential

birthof i qtest

Education

actual brain size

brain structure

cranial size

paul broca

german brain sizes

different physical characters

skull capacity

physical stature