I found this
on the web yesterday, and I'm totally confused.
I wonder if all of these professors are mistaken or they just don't like black
people. What do you think?
Racial Differences in Intelligence: What Mainstream Science Says
This public statement,
signed by 52 internationally known scholars, was active
on the information highway early in 1995 following several rather heated and
negative responses to Herrnstein & Murray's The Bell Curve. It was first
published in The Wall Street Journal, Tuesday, December 13, 1994. An
alphabetical listing of the scholars and their home institutions are given at
the end of the statement.
Since the publication
of "The BELL CURVE," many commentators have offered
opinions about human intelligence that misstate current scientific evidence.
Some conclusions dismissed in the media as discredited are actually firmly
outlines conclusions regarded as mainstream among researchers
on intelligence, in particular, on the nature, origins, and practical
consequences of individual and group differences in intelligence. Its aim is
to promote more reasoned discussion of the vexing phenomenon that the research
has revealed in recent decades. The following conclusions are fully described
in the major textbooks, professional journals and encyclopedias in
The Meaning and Measurement of Intelligence
is a very general mental capability that, among other
things, involves the ability to reason, plan, solve problems, think
abstractly, comprehend complex ideas, learn quickly and learn from experience.
It is not merely book learning, a narrow academic skill, or test-taking
smarts. Rather, it reflects a broader and deeper capability for comprehending
our surroundings -- "catching on," "making sense" of things, or "figuring out"
what to do.
2.Intelligence, so defined, can be measured, and intelligence tests
measure it well. They are among the most accurate (in technical terms,
reliable and valid) of all psychological tests and assessments. They do not
measure creativity, character, personality, or other important differences
among individuals, nor are they intended to.
3.While there are different types of intelligence tests, they all
measure the same intelligence. Some use words or numbers and require specific
cultural knowledge (like vocabulary). Others do not, and instead use shapes or
designs and require knowledge of only simple, universal concepts (many/few,
4.The spread of people along the IQ continuum, from low to high, can be
represented well by the BELL CURVE (in statistical jargon, the "normal
CURVE"). Most people cluster around the average (IQ 100). Few are either very
bright or very dull: About 3% of Americans score above IQ 130 (often
considered the threshold for "giftedness"), with about the same percentage
below IQ 70 (IQ 70-75 often being considered the threshold for mental
5.Intelligence tests are not culturally biased against American blacks
or other native-born, English-speaking peoples in the U.S. Rather, IQ scores
predict equally accurately for all such Americans, regardless of race and
social class. Individuals who do not understand English well can be given
either a nonverbal test or one in their native language. 6.The brain processes
underlying intelligence are still little understood. Current research looks,
for example, at speed of neural transmission, glucose (energy) uptake, and
electrical activity of the brain.
all racial-ethnic groups can be found at every IQ level..
The BELL CURVES of different groups overlap considerably, but groups often
differ in where their members tend to cluster along the IQ line. The BELL
CURVES for some groups (Jews and East Asians) are centered somewhat higher
than for whites in general. Other groups (blacks and Hispanics) are centered
somewhat lower than non-Hispanic whites.
2.The BELL CURVE for whites is centered roughly around IQ 100; the BELL
CURVE for American blacks roughly around 85; and those for different subgroups
of Hispanics roughly midway between those for whites and blacks. The evidence
is less definitive for exactly where above IQ 100 the BELL CURVES for Jews and
Asians are centered.
1.IQ is strongly
related, probably more so than any other single
measurable human trait, to many important educational, occupational, economic,
and social outcomes. Its relation to the welfare and performance of
individuals is very strong in some arenas in life (education, military
training), moderate but robust in others (social competence), and modest but
consistent in others (law-abidingness). Whatever IQ tests measure, it is of
great practical and social importance.
2.A high IQ is an advantage in life because virtually all activities
require some reasoning and decision-making. Conversely, a low IQ is often a
disadvantage, especially in disorganized environments. Of course, a high IQ no
more guarantees success than a low IQ guarantees failure in life. There are
many exceptions, but the odds for success in our society greatly favor
individuals with higher IQs.
3.The practical advantages of having a higher IQ increase as life
settings become more complex (novel, ambiguous, changing, unpredictable, or
multi-faceted). For example, a high IQ is generally necessary to perform well
in highly complex or fluid jobs (the professions, management); it is a
considerable advantage in moderately complex jobs (crafts, clerical and police
work); but it provides less advantage in settings that require only routine
decision making or simple problem solving (unskilled work).
4.Differences in intelligence certainly are not the only factor
affecting performance in education, training, and highly complex jobs (no one
claims they are), but intelligence is often the most important. When
individuals have already been selected for high (or low) intelligence and so
do not differ as much in IQ, as in graduate school (or special education),
other influences on performance loom larger in comparison.
5.Certain personality traits, special talents, aptitudes, physical
capabilities, experience, and the like are important (sometimes essential) for
successful performance in many jobs, but they have narrower (or unknown)
applicability or "transferability" across tasks and settings compared with
general intelligence. Some scholars choose to refer to these other human
traits as other "intelligences."
Source and Stability of Within-Group Differences
differ in intelligence due to differences in both
their environments and genetic heritage. Heritability estimates range from 0.4
to 0.8 (on a scale from 0 to 1), most thereby indicating that genetics plays a
bigger role than does environment in creating IQ differences among
individuals. (Heritability is the squared correlation of phenotype with
genotype.) If all environments were to become equal for everyone, heritability
would rise to 100% because all remaining differences in IQ would necessarily
be genetic in origin.
2.Members of the same family also tend to differ substantially in
intelligence (by an average of about 12 IQ points) for both genetic and
environmental reasons. They differ genetically because biological brothers and
sisters share exactly half their genes with each parent and, on the average,
only half with each other. They also differ in IQ because they experience
different environments within the same family.
3.That IQ may be highly heritable does not mean that it is not
affected by the environment. Individuals are not born with fixed, unchangeable
levels of intelligence (no one claims they are). IQs do gradually stabilize
during childhood, however, and generally change little thereafter.
4.Although the environment is important in creating IQ
differences, we do not know yet how to manipulate it to raise low IQs
permanently. Whether recent attempts show promise is still a matter of
considerable scientific debate. 5.Genetically caused differences are not
necessarily irremediable (consider diabetes, poor vision, and phenal
ketonuria), nor are environmentally caused ones necessarily remediable
(consider injuries, poisons, severe neglect, and some diseases). Both may be
preventable to some extent.
Source and Stability of Between-Group Differences
1.There is no
persuasive evidence that the IQ BELL CURVES for different
racial-ethnic groups are converging. Surveys in some years show that gaps in
academic achievement have narrowed a bit for some races, ages, school subjects
and skill levels, but this picture seems too mixed to reflect a general shift
in IQ levels themselves.
2.Racial-ethnic differences in IQ BELL CURVES are essentially the same
when youngsters leave high school as when they enter first grade. However,
because bright youngsters learn faster than slow learners, these same IQ
differences lead to growing disparities in amount learnedas youngsters
progress from grades one to 12. As large national surveyscontinue to show,
black 17-year-olds perform, on the average, more likewhite 13-year-olds in
reading, math, and science, with Hispanics inbetween.
3.The reasons that blacks differ among themselves in intelligence
appear to be basically the same as those for why whites (or Asians
orHispanics) differ among themselves. Both environment and geneticheredity are
4.There is no definitive answer to why IQ bell curves differ
acrossracial-ethnic groups. The reasons for these IQ differences betweengroups
may be markedly different from the reasons for why individualsdiffer among
themselves within any particular group (whites or blacks orAsians). In fact,
it is wrong to assume, as many do, that the reason whysome individuals in a
population have high IQs but others have low IQs must be the same reason why
some populations contain more such high (or low) IQ individuals than others.
Most experts believe that environment is important in pushing the bell curves
apart, but that genetics could be involved too.
5.Racial-ethnic differences are somewhat smaller but still substantial
for individuals from the same socioeconomic backgrounds. To illustrate, black
students from prosperous families tend to score higher in IQ than blacks from
poor families, but they score no higher, on average, than whites from poor
6.Almost all Americans who identify themselves as black have white
ancestors -- the white admixture is about 20%, on average -- and many self-
designated whites, Hispanics, and others likewise have mixed ancestry. Because
research on intelligence relies on self-classification into distinct racial
categories, as does most other social-science research, its findings likewise
relate to some unclear mixture of social and biological distinctions among
groups (no one claims otherwise). The average I.Q for African blacks was
found to be 75, the higher intelligence of American blacks is due to the
percentage of white blood that is characteristic of American blacks.
Implications for Social Policy
findings neither dictate nor preclude any particular social
policy, because they can never determine our goals. They can, however, help us
estimate the likely success and side-effects of pursuing those goals via
professors -- all experts in intelligence and allied fields --
have signed this statement:
•Richard D. Arvey,
University of Minnesota •Thomas J. Bouchard, Jr.,
University of Minnesota •John B. Carroll, Un. of North Carolina at Chapel Hill
•Raymond B. Cattell, University of Hawaii •David B. Cohen, University of Texas
at Austin •Rene V. Dawis, University of Minnesota •Douglas K. Detterman, Case
Western Reserve Un. •Marvin Dunnette, University of Minnesota •Hans Eysenck,
University of London •Jack Feldman, Georgia Institute of Technology •Edwin A.
Fleishman, George Mason University •Grover C. Gilmore, Case Western Reserve
University •Robert A. Gordon, Johns Hopkins University •Linda S. Gottfredson,
University of Delaware •Robert L. Greene, Case Western Reserve University
•Richard J.Haier, University of Callifornia at Irvine •Garrett Hardin,
University of California at Berkeley •Robert Hogan, University of Tulsa
•Joseph M. Horn, University of Texas at Austin •Lloyd G. Humphreys, University
of Illinois at Urbana-Champaign •John E. Hunter, Michigan State University
•Seymour W. Itzkoff, Smith College •Douglas N. Jackson, Un. of Western Ontario
•James J. Jenkins, University of South Florida •Arthur R. Jensen, University
of California at Berkeley •Alan S. Kaufman, University of Alabama •Nadeen L.
Kaufman, California School of Professional Psychology at San Diego •Timothy Z.
Keith, Alfred University •Nadine Lambert, University of California at Berkeley
•John C. Loehlin, University of Texas at Austin •David Lubinski, Iowa State
University •David T. Lykken, University of Minnesota •Richard Lynn, University
of Ulster at Coleraine •Paul E. Meehl, University of Minnesota •R. Travis
Osborne, University of Georgia •Robert Perloff, University of Pittsburgh
•Robert Plomin, Institute of Psychiatry, London •Cecil R. Reynolds, Texas A &
M University •David C. Rowe, University of Arizona •J. Philippe Rushton, Un.
of Western Ontario •Vincent Sarich, University of California at Berkeley
•Sandra Scarr, University of Virginia •Frank L. Schmidt, University of Iowa
•Lyle F. Schoenfeldt, Texas A & M University •James C. Sharf, George
Washington University •Herman Spitz, former director E.R. Johnstone Training
and Research Center, Bordentown, N.J. •Julian C. Stanley, Johns Hopkins
University •Del Thiessen, University of Texas at Austin •Lee A. Thompson, Case
Western Reserve University •Robert M. Thorndike, Western Washington Un.
•Philip Anthony Vernon, Un. of Western Ontario •Lee Willerman, University of
Texas at Austin