Intelligence Testing

Intelligence Testing March 8, 2006 Pauline Yu and Neha Begwani

History • “I advance it, therefore, as a suspicion only, that the blacks, whether originally a distinct race, or made distinct by time and circumstance, are interior to the whites in he endowment both of body and of mind.” Thomas Jefferson

Craniometry • George Morton • Hypothesis: “objectively by physical characteristics of the brain, particularly by its size.” • Approximate intelligence by measuring the volume of the cranium • Large sources of bias in methodology

Morton’s Results

Brain Size as Proxy for Intelligence • Correlation between body size and cranium size • “This fact does not imply that big people are smarter—any more than elephants should be judged more intelligent than humans because their brains are larger.” (Gould, 61)

Bias in Sample Size • Morton’s experimentation suffered from disproportionate sample size • Unequal representation of subgroups within a race group • Native American sample • 25% was the smaller brained Inca Peruvians • 2% was the larger brained Iroquois

Morton’s Subconscious • Bias from subconscious belief in superiority of white race • Packing the craniums of white subjects as tightly as possible • Did not put same effort for Black and Native American Races • Rounded results to further skew data

Racial Comparisons Paul Broca (1824-1880) compared the radius:humerus ratios in humans (larger ratio = longer forearm) Apes have long forearms

Ratios • Whites - 0.739 • Blacks - 0.794 But….. • Eskimos - 0.703 • Native Americans - 0.709 • Broca concluded: “After this, it seems difficult to say that elongation of the forearm is a character of degradation or inferiority”

Stanford-Binet Test Sample Questions (1911 Version): An Indian who had come to town for the 1st time in his life saw a white man riding across the street. As the white man rode by, the Indian said - “The white man is lazy; he walks sitting down.” What was the white man riding on that caused the Indian to say, “He walks sitting down.” My neighbor has been having queer visitors. First a doctor came into the house, then a lawyer, then a minister. What do you think happened there?

Catherine Cox Some of her results: Average A1 IQ (birth-17) - 135 Average A2 IQ (17-24) - 145 Major flaw - IQ is not supposed to alter with age. “Normal” IQ Range: 85-115 • Attempted to estimate the IQs of 282 geniuses • Flawed and illogical but… from this study she earned a PhD from Stanford!

Yerkes and the Army Exams “Examinations Alpha and Beta are so constructed and administered as to minimize the handicap of men who because of foreign birth or lack of education are little skilled in the use of English. These group examinations were originally intended and are now definitely known to measure native intellectual ability.” - Yerkes

Army Examination (Alpha) • The most prominent industry in Detroit is (A)automobiles (B) brewing (C) flour (D) packing • Velvet Joe appears in advertisements for (A) tooth powder (B) dry goods (C) tobacco (D) soap Results: Average mental age of white American adults stood at 13! European immigrants: Russian - 11.34, Italian -11.01, Pole - 10.74 IQ = (Mental Age / Actual Age) X 100

IQ Testing Today • Major Cultural Biases in Testing: • Non-verbal Raven’s test vs. highly verbal Peabody Picture test • BITCH test developed to counter the cultural differences

Intelligence Testing