1. PowerPoint® Presentation by Jim Foley
Thinking, Language, and Intelligence
PowerPoint® Presentation
by Jim Foley
© 2013 Worth Publishers

2. Module 31: Influences on Intelligence: Genes and Environment

3. 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
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4. 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.
Click to reveal bullets.
Note that no commonly accepted definition of “successful” exists so that the entire question is probably better suited to philosophy than psychology. You might ask students to try to define “success”—socioeconomic status? self-reported claims to happiness? achievement (another difficult word to define)? celebrity status? public acclaim?

5. Genetic and Environmental Influences on Intelligence Studies of Twins Raised Apart
What explains this difference?
What explains this difference?
Findings from these studies indicate that both nature and nurture affect intelligence test scores.
Click to show questions and answers about the graph.
The first two bars differ because of differences in rearing/environment, since the genetics did not change; rearing the twins apart reduced the similarity. The first and third bar may differ because of genetics, since they were reared together in both cases; having more identical genes increased the similarity of intelligence scores.

6. Heritability Clarifying Heritability
If three people had exactly the same education, nutrition, and experiences, some psychologists speculate that genes might be responsible for perhaps 40 percent of their intelligence; nurture certainly made a big impact.
However, such identical nurturing (which is actually impossible) could not create differences in intelligence.
With identical nurture, the heritability of intelligence would be virtually 100 percent.
When you see variation in intelligence between two or more people, the heritability of that trait is the amount of variation that is apparently explained by genetic factors.
This does NOT tell us the proportion that genes contribute to the trait for any one person.
Click to reveal bullets.
The slide has appeared before in the chapter on nature and nurture.
The heritability of a trait also does NOT tell us whether genetics explain differences between groups/populations. Height is 90 percent heritable in general, but as a group, people are taller in this century than last, or in South Korea compared to North Korea. This is probably not caused by genetics but by nurture (nutrition).
Click to reveal sidebar bullets.
Note: there is a similar slide in the “Nature-Nurture” chapter which originally used intelligence as the example and now has been revised to discuss sociability.
Of course identical nurture is not possible; tiny differences, even in utero, can begin the epigenetic process of turning genes on and off.

7. 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.
Click to reveal bullets.

8. 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.
Click to reveal chart.
Answer: birth/biological parents. This will seem counterintuitive to many students. Suggest that they notice that their parents may be having increasingly less influence on their talents.
You may want to restate this result in a way that ties back to the heritability concept; the heritability of intelligence test scores increases with age.

9. 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.
Click to reveal bullets.
When environment/nurture varies more, its influence on intelligence increases.
Pictured in the slide is a Romanian orphan who suffered from deprivation of human interaction.
The impact of tutored enrichment can be compared to the impact of multi-vitamins, which make a bigger difference for those who were malnourished than for those who eat healthy meals.
The impact of educational videos does not seem to be great for any group, especially when it substitutes for face to face interaction.

10. 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.
Click to reveal bullets.
Instructor: you might ask students, “What might it imply about intelligence test scores if they can be affected by schooling and attitude?”

11. 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.
Click to reveal bullets.

12. Supposed Male-Female Ability Differences
Male/female difference related to overall intelligence test score.
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Instructor: clarify for students that this graph of scores by IQ level does not replace the normal curve. It IS the same people in the normal curve, but split into percentage male and percentage female. Males with IQ ‘x’ plus females at IQ ‘x’ equals 100 percent of the people at IQ ‘x’.
You can ask students, then, what they can say about boys and girls and their ranges of IQ scores? A final click reveals an answer at the bottom of the slide.
Boys are more likely than girls to be at the high or low end of the intelligence test score spectrum.

13. 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.
Click to reveal bullets.
Question to raise with students: do you think that these differences are caused by genetics and strengths developed through natural selection, or because boys and girls are raised differently?

14. Tests of Male and Female Strengths
Standard
After you have clicked and the classroom picture and moving rock have disappeared, have students do the “male” block configuration test first.
Please practice using this slide in slide show mode.
[Answer: the two right most circles. I moved and rotated some of the ones from the text to make it harder to simply look at the book for answers]
Then do the “female” object location memory test: ask who can remember where the rock started and where it ended up.

15. 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.
Click to animate graph.
Click to reveal remaining bullets.
The following statement perhaps gives too much away before seeing if students can figure out the concept on the next slide, but I included here as material for explaining the next slide: “But first we must train ourselves to see that differences between groups can be caused by environmental factors (even identical twins can have differences in height, sexuality, and ability).
Remind students that even the term “African American” has little or no meaning; is it self-defined or can someone determine who fits in this category? Do Egyptians and Algerians count? Are Bantu peoples to be lumped in with Khoisan? Is the American “one drop of blood” rule to be used to determine “African American-ness,” or a different standard from Brazil or Trinidad?
Remind students that a future slide notes that racial categories are not distinct genetically.
But first…

16. 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).
No animation.
Instructor: have students think about what they assume causes the difference between the two groups of flowers. After you ask this question and hear some answers, click to reveal that both groups of flowers are from the same seed packet. Again, even identical twins can have differences in height, sexuality, and ability.

17. 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 1930s.
“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.
Click to reveal bullets.

18. Two Problems Called “Bias”
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 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.
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.
Click to reveal bullets.
Click to reveal sidebar bullets.
A question to ask students to test their learning: “what quality of good tests have we just identified in the last sentence?”...predictive validity.
Angela Garcia, executive director of the SAT program, defended the prompt: “It’s really about pop culture as a reference point that they would certainly have an opinion on.” You might ask students if they agree.
Note: “racial” differences persist on skills such as repeating digits backward. Do these skills also depend on cultural experience?

19. 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?
Click to reveal three questions.
Instructor: 
Simple answer to all three questions:  They fell victim to the effect known in psychology as Stereotype Threat (explained next slide). You can change the title of the slide if you just want to test students on the name of the concept, or you can ask them to explain how it works before you go to the next slide.
NOTE:  Some students may be uncomfortable with the way the terms "Black" and even "race" are used in the study cited by the text. Although we can't make an exact determination of someone's race, we can determine whether someone identifies themselves as being part of a stereotypically lower-status group, and that's what's relevant in this study, that's what apparently triggered the effects on performance, as we'll see on the next slide.
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?

20. 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 self- confirming/fulfilling: the effect of minority status on performance is worsened by worry about that effect.
Click to reveal bullets.
A self fulfilling prophecy occurs when the act of making a prediction about the future leads to that prediction coming true. Is stereotype threat an example of a self fulfilling prophecy?
The book’s definition of stereotype threat includes “self-confirming” as part of the definition.
One possible implication of the stereotype threat is that programs to support members of minority groups may hurt people’s performance when they imply that minorities need more help than others, especially when it is implied that help is needed inherently rather than situationally (the fundamental attribution error). Of course, this implication needs to be measured versus other factors (such as ongoing discrimination or socio-economic disadvantage).

21. 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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