Thinking Language and Intelligence Power Point Presentation by
Thinking, Language, and Intelligence Power. Point® Presentation by Jim Foley © 2013 Worth Publishers
Module 31: Influences on Intelligence: Genes and Environment
Overview: What we are born with, what we can change § § § § Heritability Results from Twin and Adoption Studies Environmental Influences: Early Childhood and School Group Differences in Intelligence Scores: Due to Genes or Environment? Gender Similarities and Differences in IQ scores Racial/Ethnic Similarities and Differences in IQ scores The Effect of Stereotype threat on IQ scores Two Meanings of “Bias” in test design: group harm vs. predictive effectiveness
Genetic and Environmental Influences on Intelligence (Nature and Nurture) § Even if we agree for argument’s sake that “success” in life is caused in part by some kind of intelligence, there is still a debate over the origin of that intelligence. – Are people “successful” because of inborn talents? – Or are they “successful” because of their unequal access to better nurture? § Information to tease out the answers can be found in some twin and adoption studies.
Genetic and Environmental Influences on Intelligence Studies of Twins Raised Apart What explains this difference? Findings from these studies indicate that both nature and nurture affect intelligence test scores.
Clarifying Heritability § If three people had exactly the same education, § When you see variation nutrition, and experiences, in intelligence between some psychologists speculate two or more people, the that genes might be heritability of that trait responsible for perhaps 40 is the amount of percent of their intelligence; variation that is nurture certainly made a big apparently explained by impact. genetic factors. § However, such identical § This does NOT tell us the nurturing (which is actually proportion that genes impossible) could not create contribute to the trait for differences in intelligence. any one person. § With identical nurture, the heritability of intelligence would be virtually 100 percent.
Genetic Influences on Intelligence § Identical twins seem to show similarity in specific talents such as music, math and sports. § The brains of twins show similar structure and functioning. § There are specific genes which may have a small influence on ability.
Adoption Studies With age, the intelligence test scores of adoptees looks more and more like that of their ______ parents. (adoptive? birth/biological? ) In another study, heritability of intelligence test scores continued to increase beyond age 16.
Environmental Influences on Intelligence § Environment has more influence on intelligence under extreme conditions such as abuse, neglect, or extreme poverty. § Tutored human enrichment has a larger impact on compensating for deprivation than on boosting intelligence under normal conditions.
Schooling and Intelligence § Preschool and elementary school clearly have at least a temporary impact on intelligence test scores. § College can have a positive impact on intelligence test scores if students have: – motivation and incentives. – belief that people can improve. – study skills, especially the willingness to practice.
Understanding Group Differences in Test Scores Now, let’s look at: § gender differences. § “racial” differences. § understanding the impact of environment. § within-group differences and between-group differences. § the impact of test bias and stereotype threat on performance.
Supposed Male-Female Ability Differences Male/female difference related to overall intelligence test score. Boys are more likely than girls to be at the high or low end of the intelligence test score spectrum.
Male-Female Ability Differences § Girls tend to be better at spelling, locating objects, and detecting emotions. § Girls tend to be more verbally fluent, and more sensitive to touch, taste, and color. § Boys tend to be better at handling spatial reasoning and complex math problems. § It is a myth that boys generally do better in math than girls. Girls do at least as well as boys in overall math performance and especially in math computation.
Tests of Male and Female Strengths Standard
Ethnic/Racial Differences in Intelligence Test Scores The bell curve for African American intelligence test scores is centered at 85. For non-African Americans, the average is 100. Whatever the cause of this score difference, it is incorrect to use this information to predict the score of an individual. The green triangle shows African-Americans scoring higher than the average non. African-Americans. How can we interpret this group difference in average intelligence test scores? We will look at the issue of test bias and other factors affecting scores for perceived minorities. But first…
Understanding Group Differences: Within-group vs. Between-group Group differences, including intelligence test score differences between so-called “racial groups, ” can be caused by environmental factors. Below: the difference between groups is caused by poor soil (environment).
The “Racial” Intelligence Test Score Gap § Racial categories are not distinct genetically and are unscientific. § Both “whites” and “blacks” have higher intelligence test scores than “whites” of the 1930 s. § “Whites” may have more access to “fertile soil” for developing their potential, such as: § schools and educational opportunities. § wealth, nutrition, support, and educated mentors. § relative freedom from discrimination.
Two Problems Called “Bias” Test makers must prevent “bias” in the popular sense of the word: making it easier for one group than another to score high on a test. Test makers also strive to prevent the scientific form of bias: making it easier for one group than for another to have their abilities accurately assessed, and their future performance predicted. Are Tests Biased? Bias 1: In the popular sense of the word, intelligence tests are often biased. Often, tests have questions which rely on knowledge of mainstream culture. For example, the 2011 SAT writing prompt demanded students discuss the authenticity of reality television shows. Bias 2: Aptitude tests seem to predict future achievement equally well for various ethnic groups, and for men and women.
The Effect of Stereotype Threat Study result: Blacks/African-Americans scored higher when tested by Blacks rather than being tested by Whites. Why? Study result: Blacks/African-Americans did worse on intelligence tests when reminded of their racial/ethnic identification right before the test. Why? Study result: Women did worse on math tests than men, except when they are told first that women usually do as well as men on the test. Why?
The Power of Expectations § Stereotype threat refers to a feeling that one will be evaluated based on a negative stereotype. § Stereotype threat may interfere with performance by making people use their working memory for worrying instead of thinking. § This worry is selfconfirming/fulfilling: the effect of minority status on performance is worsened by worry about that effect.
Issues Related to Intelligence Tests Is discriminating among college or job applicants based on test scores better than discriminating based on appearance? Can test scores be used as Alfred Binet suggested: to identify those who would benefit from educational interventions? Can a person’s worth and potential be summed up in one intelligence test score?
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