Intelligence Testing
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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
Number of
Observations
Caucasian 52
Asian
10
Polynesian 18
Native
147
American
African
29
Race
Mean
Largest Smallest
87
83
81
82
109
93
89
100
75
69
64
60
78
94
65
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
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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
Attempted to
estimate the IQs
of 282 geniuses
Flawed and
illogical but…
from this study
she earned a
PhD from
Stanford!
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
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