PPT 4 Flashcards
Misuses of IQ Testing
Tragically, history is replete with misuses of intelligence testing
Early 20th Centruy
IQ tests fueled the Eugenics movement by establishing the heritability of intelligence and using that to discriminate
Identifying “feebleminded” people in an effort to keep them from having children (1912)
Leading to the involuntary sterilization of 65,000 people with “low IQ” (disproportionately poor and people of color)
Terman’s Claims (1916)
(from Alea Holman, 2022)
Terman (a highly regarded professor at Stanford) argued that certain races had genetically lower IQs than whites and that “no amount of school instruction will ever make them intelligent voters or capable citizens.”
He asserted that such lower IQs were “very common among Spanish-Indian and Mexican families of the Southwest and also among negroes [sic].”
Terman recommended that “Children of these groups should be segregated in special classes and be given instruction that is practical” and concluded that “they cannot master abstractions, but they can often be made efficient workers.”
“The science of intelligence testing authoritatively justified separate curricula for allegedly backward groups” (Blanton, 2003)
Continuing the Claims of Racial Differences in Intelligence
Arguing the mean Black-White differences in IQ scores had a large genetic component (Jensen, Rushton and others starting in the 1960’s and continuing)
Claiming racial groups have different mean IQs and those differences are based in genetics. Attributing lack of social mobility in part to intelligence. (The Bell Curve, Hernstien & Murray, 1994)
Advocating that the mean IQ of different nations explained why some nations are less advanced (Lynn & Vanhanen and others)
Language
Language is perhaps the biggest and most systematic confound in measuring intelligence across context/cultures
- Familiarity matters
The Flynn Effect
Flynn, J.R. (1999). Searching for Justice: The discovery of IQ gains over time. American Psychologist, 54, 5-20.
Gathered data from 73 studies on 7,500 people ages 2 to 48 between 1932 and 1968
- Results showed a gain of 14 IQ points
- .3 points per year, 3 points every 10 years
- Roughly uniform over time and similar for all ages
- Rapid changes
“A secular increase in population IQ observed throughout the 20th century”
Possible Reasons for the Flynn Effect
- Nutrition
- Television
- Test sophistication – no evidence
- Enhanced SES
- Urbanization
- Better education
- Video games (Similarities is largest gainer)
Flynn Effect Revisited (Russell, 2007)
Evidence suggests that the Flynn effect is reaching a plateau in some societies, perhaps as they reach optimal social environments
Nesbit, Blair, Dickens, Flynn, Halpern & Turkheimer (2012)
Update of APA position paper by Neisser, Boodoo, Bouchard, Boykin, Brody, Ceci, Halpern, Loehlin, Perloff, Sternberg, & Urbina (1996)
Incorporates a lot of studies
Measurement of Intelligence (Nesbit et al)
“One of psychology’s greatest achievements and one of its most controversial”
Evidence that Black-White differences are diminishing
From 1972 to 2002 there is evidence that the gap between Black and White children diminished by 5.5 IQ points
Debate Dickens & Flynn (2006) vs Rushton & Jensen (2006)
White - Asian Differences
Similar IQ but Asians show higher achievement (SAT)
Emphasis in Asian culture on achievement may at least in part explain this.
Jewish vs. Non-Jewish
People of Jewish heritage show an estimated 7 to 15-point advantage over white non-Jews on IQ scores
May reflect cultural differences or may reflect biology
Genes and the Environment (Nesbit et al)
Both genes and environment affect IQ
**Heritability of IQ ~between .4 and .8 (more recent estimate than Bouchard twin study .3 to .5 estimate)
- Heritability estimates lower for children and higher for adults
But “it makes no sense to talk about a single value for the heritability of intelligence, in part because heritability is relative to the population studied”
IQ Tests as Predictors (Nesbit et al)
IQ scores predict school performance (and achievement test scores) pretty well
- The correlation between IQ and performance is seemingly ubiquitous
IQ scores predict Years of Education
- Test scores are best single predictor of years of education
IQ predicts occupation level, social class, and (thus) income
- *maybe because it predicts education?