IQ as a Predictor school performance/GPA : r = .50 between IQ and grades o other factors: motivation, persistence, teaching years of education : r = .55 o other factors: teacher effect, good grades social status and income/lower or middle class : r = .33 between IQ and parent SES o other factors: years of education o kids who are born to parents who are wealthy tend to have a higher IQ than those who are born to poor parents job performance (promotions, etc.) : r = .30-.50 o other factors: interpersonal skills, personality o but IQ scores are a much better predictor than job interview social outcomes : IQ has a small negative correlation with crime Environmental Effects on Intelligence cultural environment urban/rural differences (~2 IQ points) schooling (IQ has been found to drop by 6 points for each year of school missed) Interventions: o Head Start: no long-term IQ differences but less likely to be in spec. ed, held back, or drop out o not so with more extensive programs family—life style may not make a great contribution Biological Effects on Intelligence Nutrition—prolonged malnutrition during childhood lowers IQ o need more studies on effects of individual nutrients o Mercury; Minamata disease (factory dumped waste in a Minamata bay; abnormal shaped of heads, motor problems; mercury given to cats and they started to display the same types of behavior that we seen in humans) Lead exposure negatively correlated with IQ prenatal alcohol use—5 points lower on IQ at age 4 very low birth weight—severe or permanent intellectual deficits The Flynn Effect IQ scores have risen worldwide (~3 points/decade) o More than 15 points in last 50 years
Tests restandardized periodically to adjust Why is IQ rising continually? 1. cultural differences between generations: technology and life complexity 2. better nutrition 3. better education/test-taking skills 4. we are defining intelligence wrongly Group Differences Group differences say a little about an individual’s performance. Differences within each group are greater than the average differences between groups. It is NOT appropriate to determine superiority/inferiority of certain groups based on IQ differences. Sex Differences Females and males are generally similar on total IQ scores. Differences to appear in specific abilities: o Men are in general better at visual-spatial tasks (blocks, putting pictures in order to tell a story, etc.) o Females generally better at verbal tasks (fluency/speaking, spelling, emotion-detecting, and sensation o Females are better at math until around puberty, then men are better into old age (most chess champions and engineers are men) o Explanations: different sizes of brain structures associated with verbal fluency, hormone levels Racial/Group Differences Asian Americans score higher than everyone.