Download Race, Genetics, and Intelligence

Race, Genetics, and
Intelligence
The Effects of Race on
Intelligence Test Scores
Mary Adams
April 3, 2006
How much do you know about race?
Humans have approximately 30,000 genes. On
average, how many genes separate all members
of a race from all members of another race?
A.None
B.1
C.23
D.142
E.1008
F.We don’t know
California Newsreel (2003)
How much do you know about race?
Which continent has the greatest human
genetic diversity?
A.Europe
B.Asia
C.Africa
D.North America
E.South America
California Newsreel (2003)
How much do you know about race?
Who was the first American public figure to suggest,
albeit "as a suspicion only," that black people might be
inherently inferior to whites?
A.Thomas Jefferson
B.Sir Walter Raleigh
C.George Washington
D.Robert E. Lee
E.Capt. John Smith, founder of the Jamestown colony
California Newsreel (2003)
The Genetics of Race
• Not one gene distinguishes members of one race
from members of another
• There is more genetic variation within races than
between them
– 2 random Koreans are likely to be as genetically
different as a Korean and an Italian
• Most traits are inherited independently of each
other
- Genes for skin color have nothing to do
with hair type, musical talent, blood
type, or athletic ability
Sternberg, Grigorenko, & Kidd (2005)
California Newsreel (2003)
The Social Aspect of Race
• In ancient societies, people were differentiated on the
basis of culture and language, not physical
appearance
• Concept of race developed by 18th century naturalists,
such as Charles Linnaeus
• 1776: The ideas of American freedom and racial
inequality developed concurrently in the United States
– To maintain and justify the slave trade, the inferiority of
certain races was established
Sternberg et al. (2005)
California Newsreel (2003)
The Social Aspect of Race
• Different cultures define race differently
– “Caucasian”:
• United States: preferred term for whites
– Positive connotation
• Russia: refers to people from the Caucuses who are generally
dark compared to other Russians
– Viewed with suspicion because of political unrest in the region
– Skin color is not always the basis for defining race
• Rwanda:
– Hutus and Tutsis distinguished based on other physical
characteristics, such as height
• Nazi Germany: racial labeling used to advance political aims
– “Aryan Race,” “German Race,” “Jewish Race”
Sternberg et al. (2005)
Race and Cognitive Ability
• Cross-Cultural: Asian vs. American Math Scores
– 1980’s: International Project for the Evaluation of
Educational Achievement (IEA)
– American students scoring in the 95th percentile in the
United States would score in the 30th percentile in
Japan
– The top 5% of American students had only average
scores in relation to the international standards in
algebra and calculus
Geary (1996)
Race and Cognitive Ability
• United States: Differences in standardized test
scores
– African Americans and Hispanics consistently score
lower than whites
– Whites consistently score lower than Asians
• Herrnstein and Murray (1994) compiled scores from cognitive
standardized tests over an 80 year period
• African Americans consistently scored, on average, between
0.8-1.2 standard deviations below whites
Herrnstein & Murray (1994)
Race and Cognitive Ability
• The race gap in standardized test scores is
prominent in the SAT
Verbal SAT Score and Math SAT Score Distributions of
Applicants to Five Selective Institutions, by Race, 1989
Bowen (1998)
Cause of Disparity: Genetics
• The Facts
– Little genetic similarity within a single race
– Race is at least partially a social construct
– No intelligence gene has been isolated
• Conclusion
– racial differences in intelligence are
probably not due to the genetic superiority
or inferiority of certain “races”
Sternberg et al. (2005)
Cause of Disparity: Environment
• Cross Culturally
– Language: structure of number words
• Asian: 11, 12, 13,… is “ten-one, ten-two, ten-three”
• European: no straightforward correspondence between
number words from 11-100
– Schooling: American curriculum is poorly organized and
too easy by international standards
• Topics introduced in the 5th or 6th grade in the United States are
introduced in 2nd or 3rd grade in Japan, China, and Taiwan
– Cultural Values
• Different cognitive-educational emphases
• Structure of educational opportunities
–Second chances are more common in the United States
Geary (1996)
Cause of Disparity: Environment
• Within the United States
–
–
–
–
–
–
–
–
Socioeconomic status
Quality of schooling
Family environment
External and internal testing bias
Lack of motivation
Less access to coaching
Less experience with tests
Stereotype Threat
Herrnstein & Murray (1994)
References
Bowen, W. G., & Bok, D. (1998). The shape of the river: Long-term consequences of
considering race in college and university admissions. Princeton, N.J.: Princeton
University Press.
California Newsreel (2003). Race: The power of an illusion. www.pbs.org/race
California Newsreel (2003). Race literacy quiz: What differences make a difference?
www.newsreel.org/guides/race/quiz.htm
Geary, D. C. (1996). International differences in mathematical achivement: Their nature,
causes, and consequences. Current Directions in Psychological Science, 5, 133-137.
Herrnstein, R. J., & Murray, C. (1994). The bell curve. New York: Free Press.
Sternberg, R. J., Grigorenko, E. L., & Kidd, K. K. (2005). Intelligence, race, and genetics.
American Psychologist, 60, 46-59.